Rockets Are Good Enough
Rand Simberg
http://www.foxnews.com/story/0,2933,61066,00.html
--
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"Extraordinary launch vehicles require extraordinary markets..."
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Jim Kingdon
Hmm. Using the word "supersonic" without defining it might be OK, but
"hypersonic" and the difference between that and "supersonic"
definitely need an explanation for this audience. Likewise for the
difference between "oxidizer" and "fuel". I might have also started
off with a little more about the scramjet hype and such, rather than
just jumping into the technical issues.
I can see the reason to include some discussion of technical issues,
since after all, these ultimately do provide the pros and cons for
rocket vs. airbreather. The Fox News audience would be interested in
what the difference is. But you can't assume the same kind of a
priori knowledge as in this newsgroup...
John Doe
> http://www.foxnews.com/story/0,2933,61066,00.html
I don't really disagree, but:
> So even a vehicle that has to carry all of its own oxidizer will be less
> than twice the mass of one that doesn't.
If you consider a hydrogen-oxygen chemical propulsion, you need about
16 tons of oxygen for every 2 tons of hydrogen, whatever the form you
store them in. Even if you don't save all the oxidizer by using an
airbreathing engine, it really could make a big difference on mass
(and hence liftoff thrust, structure, etc.)
Or maybe you meant "size" or "volume"?
This is a spam-bait; any mail sent to any of these email addresses will
go through an open-relay scanner.
Geraldo Sazias
"Rand Simberg" <simberg.i...@trash.org> wrote in message
news:3d7e296e....@nntp.ix.netcom.com...
Most of the arguments in the article are valid: the high speeds of a
scramjet flying through the atmosphere gives rise to enormous drag which
will have to be overcome by yet more fuel, oxidizer costs next to nothing
and there isn't a big weight advantage if you take into account the fact
that a scramjet based RLV would need three if not four kinds of engines to
work.
On the other hand, rockets are dangerous devices which, IMHO can never
attain the level of reliabillity, cost effectiveness and safety of a
(scram)jet engine. This will be a very important aspect if commercial space
tourism is ever going to take off.
Therefore, I wouldn't discount scramjets in becoming an important part of
the puzzle to propel mankind into space.
Rand Simberg
John.D...@comelec.enst.fr (John Doe) made the phosphor on my
monitor glow in such a way as to indicate that:
>> So even a vehicle that has to carry all of its own oxidizer will be less
>> than twice the mass of one that doesn't.
>
>If you consider a hydrogen-oxygen chemical propulsion, you need about
>16 tons of oxygen for every 2 tons of hydrogen, whatever the form you
>store them in. Even if you don't save all the oxidizer by using an
>airbreathing engine, it really could make a big difference on mass
>(and hence liftoff thrust, structure, etc.)
>
>Or maybe you meant "size" or "volume"?
I was referring to dry weight, which is one of the main parameters
used for parametric costing, though GLOW is a factor as well.
Rand Simberg
Sazias" <re...@in.newsgroup> made the phosphor on my monitor glow in
such a way as to indicate that:
>On the other hand, rockets are dangerous devices which, IMHO can never
>attain the level of reliabillity, cost effectiveness and safety of a
>(scram)jet engine.
Ther is no basis for this statement.
Geraldo Sazias
> On Fri, 23 Aug 2002 02:42:58 CST, in a place far, far away, "Geraldo
> Sazias" <re...@in.newsgroup> made the phosphor on my monitor glow in
> such a way as to indicate that:
>
> >On the other hand, rockets are dangerous devices which, IMHO can never
> >attain the level of reliabillity, cost effectiveness and safety of a
> >(scram)jet engine.
>
> Ther is no basis for this statement.
The space shuttle has an expected failure rate of 1 in 100 flights, mostly
due to the relative insafety of the engines. A commercial jet engine has a
failure rate of something like 1 in 100.000 to 500.000 cycles. If one were
to do a safety analysis of a jet engine and a rocket engine I'm convinced
that the jet engine would win hands down. And don't forget that rocket
engines have been around as long, if not longer than the jet engine.
A rocket engine essentially harnesses a controlled explosion and therefore
the smallest defect will lead to catastrophic failure. I don't have a
crystal ball to tell me how safe rocket engines are going to be in the
future, but I'm convinced it's always going to be much less than that of a
jet engine. I would be surprised if the rocket engine would get up to the
level of a WWII era piston airplane engine.
Rand Simberg
Sazias" <re...@in.newsgroup> made the phosphor on my monitor glow in
such a way as to indicate that:
>> >On the other hand, rockets are dangerous devices which, IMHO can never
>> >attain the level of reliabillity, cost effectiveness and safety of a
>> >(scram)jet engine.
>>
>> Ther is no basis for this statement.
>
>The space shuttle has an expected failure rate of 1 in 100 flights, mostly
>due to the relative insafety of the engines. A commercial jet engine has a
>failure rate of something like 1 in 100.000 to 500.000 cycles. If one were
>to do a safety analysis of a jet engine and a rocket engine I'm convinced
>that the jet engine would win hands down.
Regardless of the fact that you're convinced, you haven't provided any
justification for that statement. You're comparing a single design,
whose primary requirement was *not* reliability or long life, with a
very mature industrial component with millions of hours of experience.
>And don't forget that rocket
>engines have been around as long, if not longer than the jet engine.
How long they've been around is irrelevant. They remain an extremely
immature technology, because no attempt has been made to mature them.
>A rocket engine essentially harnesses a controlled explosion and therefore
>the smallest defect will lead to catastrophic failure.
So does a jet engine.
>I don't have a
>crystal ball to tell me how safe rocket engines are going to be in the
>future, but I'm convinced it's always going to be much less than that of a
>jet engine.
In other words, you don't have any good reason or rationale, other
than a single past flawed attempt, yet you're convinced anyway.
>I would be surprised if the rocket engine would get up to the
>level of a WWII era piston airplane engine.
Prepare to be surprised.
Edward Wright
> rockets are dangerous devices which, IMHO can never attain the level of
> reliabillity, cost effectiveness and safety of a (scram)jet engine.
Oh? Exactly what "level of reliability, cost effectiveness and safety"
have scramjets reached? :-)
Do you have any evidence to back up your opinion?
The FAA licensed a rocketplane to fly at Oshkosh in front of 700,000
people. An aviation insurer issued the plane a $1 million liability
policy for $7000 per year. NASA had a display on scramjet technology
in one of the buildings at Oshkosh, but I don't recall their flying
any scramjets during the show.
Could you tell me where I can buy one of these safe, reliable, and
cost-effective scramjet engines? :-)
> This will be a very important aspect if commercial space
> tourism is ever going to take off.
Strange. It seems that all space tourists to date have taken off using
"dangerous rocket devices" rather than "reliable, cost-effective, and
safe" scramjets, antigravity, and other non-existant devices.
Jeff Greason
> On the other hand, rockets are dangerous devices which, IMHO can never
> attain the level of reliabillity, cost effectiveness and safety of a
> (scram)jet engine. This will be a very important aspect if commercial space
> tourism is ever going to take off.
What do you base this opinion on? While I certainly agree with
the importance of safety to space tourism, my conclusion is
quite different. Rockets are fundamentally quite simple devices,
and when designed with safety as a design constraint, can be
quite reasonable in their failure modes and effects.
The only reasons why rockets have a public image as "dangerous"
is, IMNSHO:
1) The public's experience with rocket vehicles is pretty
much limited to expendable launch vehicles with "range
destruct" packages. When there is a failure, even a
very modest failure, the range safety officer blows up
the vehicle. If jet aircraft were designed with self
destruct, they would, especially in the early years,
have generated similar hard-to-forget fireballs.
2) Many (not all!) rocket systems have not been designed
with safety and reliability as significant parameters.
The reliability record of cruise-missile jet engines,
for example, is very poor -- because they're optimized
for maximum performance in a short life. Many (not all!)
rockets are designed the same way, because of the
constraints of their vehicles. However, the De Havilland
Super Sprite and Spectre, Walter RII-203, Reaction Motors
XLR-11, Rocketdyne NF-104, and SEPR 844 engines all had
safety records which, while not perfect, were good enough
for our purposes. Nor is there any reason to believe
that these cannot be improved on.
I just checked, and as of right now we're up to 1496 engine
runs on various engines with zero uncontained failures.
While I wouldn't count out the possiblity of scramjets
being useful someday, I don't see any basis for concluding
that rockets are somehow inappropriate. Comparing the
scramjet technology of 2050 to the rocket technology of
1950 tends to, well, bias the comparison.
----------------------------------------------------------------
"Limited funds are a blessing, not Jeff Greason
a curse. Nothing encourages creative President & Eng. Mgr.
thinking in quite the same way." --L. Yau XCOR Aerospace
<www.xcor.com> <jgre...@xcor.com>
Jon Berndt
> and when designed with safety as a design constraint, can be
> quite reasonable in their failure modes and effects.
I heartily agree. Take one case in point: the space shuttle main engines. We
have flown, what is it, now, about 112 missions? That's 336 main engine
"cycles" flown over roughly twenty years. IIRC there have been only two
in-flight shutdowns, and I believe they were not even due to real engine
problems, but sensor faults. The SSMEs are also at the higher end of the
"complexity scale", are they not? Look at the OMS engines. Over the same
number of flights they have worked flawlessly if I am not mistaken. I'm not
an expert on the history of the early jet engine, but what was their safety
record early on?
Jon
Jason Rhodes
"Geraldo Sazias" <re...@in.newsgroup> wrote in message
>
> "Rand Simberg" <simberg.i...@trash.org> wrote in message
> news:3d83438c....@nntp.ix.netcom.com...
> > On Fri, 23 Aug 2002 02:42:58 CST, in a place far, far away, "Geraldo
> > Sazias" <re...@in.newsgroup> made the phosphor on my monitor glow in
> > such a way as to indicate that:
> >
> > >On the other hand, rockets are dangerous devices which, IMHO can never
> > >attain the level of reliabillity, cost effectiveness and safety of a
> > >(scram)jet engine.
> >
> > Ther is no basis for this statement.
>
> The space shuttle has an expected failure rate of 1 in 100 flights, mostly
> due to the relative insafety of the engines.
You are off by a factor of 3 here.
Jason
Len
> > http://www.foxnews.com/story/0,2933,61066,00.html
>
> I don't really disagree, but:
>
> > So even a vehicle that has to carry all of its own oxidizer will be less
> > than twice the mass of one that doesn't.
>
> If you consider a hydrogen-oxygen chemical propulsion, you need about
> 16 tons of oxygen for every 2 tons of hydrogen, whatever the form you
> store them in. Even if you don't save all the oxidizer by using an
> airbreathing engine, it really could make a big difference on mass
> (and hence liftoff thrust, structure, etc.)
>
> Or maybe you meant "size" or "volume"?
The systems effects get to you. Scramjets generally require
40 percent or so more delta vee ideal to make up for dragging
the airframe through extra atmosphere. Moreover, the *fuel*
specific impulse of a rocket is much higher than for a
scramjet. The net result of these and other factors--such
as the difficulty of bringing a regen cooled vehicle back with
no fuel to burn--generally leads to the use of much more
hydrogen than would be used in a comparable rocket. This,
in turn, can lead to a significantly larger (volume) vehicle
for the scramjet version. Finally, rocket allows the opportunity
for tricks like tri-propellants to increase density impulse--a
concept that I have advocated for four decades.
The real determinant, however, IMO, is that a scramjet ends up
with a lot more hardware, a lot more complex hardware, and a
lot more hydrogen. That's not a promising way to reduce costs.
Rocket engines are basically simple. I do not buy the argument
(in a separate post) that they are ultimately more dangerous
than a propulsion system that depends upon regen cooling of
much larger surfaces.
Best regards,
Len (Cormier)
PanAero, Inc. and Third Millennium Aerospace, Inc.
l...@tour2space.com ( http://www.tour2space.com )
Edward Wright
>>>On the other hand, rockets are dangerous devices which, IMHO can
never
>>>attain the level of reliabillity, cost effectiveness and safety of
a
>>>(scram)jet engine.
>> Ther is no basis for this statement.
> The space shuttle has an expected failure rate of 1 in 100 flights, mostly
> due to the relative insafety of the engines. A commercial jet engine has a
> failure rate of something like 1 in 100.000 to 500.000 cycles. If one were
> to do a safety analysis of a jet engine and a rocket engine I'm convinced
> that the jet engine would win hands down.
1) You're talking about a *turbojet* (or turbofan), not a *scramet*.
2) While commercial turbojets may have longer lifetimes than current
rocket engines, this is because current rocket engines have not been
*designed* for long life. There's no magic about having an inlet up
front that makes engines last longer.
> A rocket engine essentially harnesses a controlled explosion and therefore
> the smallest defect will lead to catastrophic failure.
It's combustion, not an explosion. On the other hand, most automobiles
are driven by engines that harness controlled explosions. I'm not sure
what that proves.
> I don't have a crystal ball to tell me how safe rocket engines are going
> to be in the future, but I'm convinced it's always going to be much less
> than that of a jet engine. I would be surprised if the rocket engine would
> get up to the level of a WWII era piston airplane engine.
The Unlimited racers at the National Championship Air Races use WW II
piston engines. Under race conditions, the Mean Time Before Failure is
often less than an hour. If you run the engine at military power,
however, it will last a lot longer. This is true of most engines. The
rocket engines you're talking about are designed to run at maximum
performance with minimal margins. That doesn't mean rocket engines
have to be designed and run that way.
Greg D. Moore (Strider)
"Jon Berndt" <j...@hal-pc.dot.con> wrote in message
news:ak6h2g$ast$1...@news.hal-pc.org...
> > quite different. Rockets are fundamentally quite simple devices,
> > and when designed with safety as a design constraint, can be
> > quite reasonable in their failure modes and effects.
>
> I heartily agree. Take one case in point: the space shuttle main engines.
We
> have flown, what is it, now, about 112 missions? That's 336 main engine
> "cycles" flown over roughly twenty years. IIRC there have been only two
> in-flight shutdowns, and I believe they were not even due to real engine
> problems, but sensor faults. The SSMEs are also at the higher end of the
> "complexity scale", are they not?
And that's operating them at the limits of their performance. If I redlined
my car every time I drove to the office I'd be happy if I didn't have
problems after a few commutes.
Operate a rocket engine at say 80% of rated capacity and you'll find it'll
probably have a much longer life and need a lot less repairs.
Oh, there was one other inflight shutdown, 51-L. As I understood it the
engine controllers correctly started to shut down the SSMEs once the stack
started to break up.
> Jon
>
>
>
Allen Thomson
reliable. Does anyone have their actual statistics?
David Higgins
Edward Wright wrote:
>
> It's combustion, not an explosion. On the other hand, most automobiles
> are driven by engines that harness controlled explosions. I'm not sure
> what that proves.
Technically, this isn't true, if we're speaking of gasoline
engines. They burn, not detonate, the air-fuel mixture.
Detonation (pinging, knocking) is possible, but destructive.
George William Herbert
>> >On the other hand, rockets are dangerous devices which, IMHO can never
>> >attain the level of reliabillity, cost effectiveness and safety of a
>> >(scram)jet engine.
>>
>> Ther is no basis for this statement.
>
>The space shuttle has an expected failure rate of 1 in 100 flights, mostly
>due to the relative insafety of the engines. A commercial jet engine has a
>failure rate of something like 1 in 100.000 to 500.000 cycles. If one were
>to do a safety analysis of a jet engine and a rocket engine I'm convinced
>that the jet engine would win hands down. And don't forget that rocket
>engines have been around as long, if not longer than the jet engine.
Rocket engines typically have a thrust to weight ratio of something
like 75 to 100 to 1. Jet engines typically are more like 8 to 1.
If you examine the details of the inside of modern jet engines,
the performance issues are amazing. The one thing they do have
is an industry and technical operating environment where they are
allowed to be relatively heavy, in order to gain them reliability
and maintainability.
The weight difference is where the reliability issues with rockets
all come from. Rocket engines allowed to be twice as heavy as
current ones are, using equivalent technologies and with input
from jet engine developers regarding margins and test and upkeep
processes, could certainly be made as reliable as jet engines.
A number of engineers who have worked on both have said so.
>A rocket engine essentially harnesses a controlled explosion and therefore
>the smallest defect will lead to catastrophic failure.
Detonation in a rocket engine is as unwanted as it is in a
jetliner turbofan engine or in a gas barbeque. The process is
combustion, not detonation. Propellants are mixed in an ongoing
reaction chamber with combustion occurring and burn at subsonic
velocities in the gas mixture.
Hyperbole and ignorance about the fundamental technical behaviour
of rocket engines are not an adequate replacement for actually
studying what they are and how they work.
-george william herbert
gher...@retro.com
David I. Luther
I agree that jets are not automaticly safe. Any power source capable
of doing the mission is capable of violent failure. A scram jet is
essentially still a reaction system - a form of rocket. Any failure
can be magnified by the oxidisers on board for rockets used for flight
out of the atmosphere. Adding another system adds another avenue for
failure, with limited gains.
One may build a case for turbine engines if they were used with hybrid
engines. Hybrids are not as easy to start and stop as liquid fuel,
and may need auxiliary power for return to the runway after a mission.
They may be easier to sell to the FAA for operation at civilian
airports. But hybrids may also offer a lower isp and increased weight
penalties. The jets may also require protection from reentry heating
on inlets and compressors.
Scramjets on the other hand do not come to life without some initial
speed for proper combustion. They will need a rocket boost just to
get started, as the X-43 and Austrailian vehicles did. Where is the
economy here? I hope we can find value in winged flight to space, but
I am not sure we need atmospheric oxygen. The atmosphere is not pure
Oxygen, and it thins greatly over 30,000 feet. On a trip to even just
300,000 feet, this is a small part of the journey. Scramjets may be
great for a long flight in the atmosphere though. Transport aircraft
and weapons systems will do great things with these engines. They
could even "skip" out of the atmosphere, and only return to gulp some
fresh air, like whales in the ocean.
Some study needs to go to improving the airframe and aerodynamics.
Basic physics proposed the inclined plane as a tool to lift a given
weight with reduced forces. Winged flight will add drag, and mass
which reduces the adventage. European studies have examined some
uniquely aerodynamic shapes. The right compromise of elegant
aerodynamics and efficient structural packaging could prove helpful.
There are materials coming out which can reduce weight too. These can
be flown on unmanned prototypes even before they are fully matured for
FAA approval in manned vehicles.
When the right airframe is ready I expect rockets will still be the
prime mover. And when safety is required, no one has demonstrated
more effective proof than Xcor. We were able to view your
demonstrations at Oshkosh, and even indoors, in safety. That came
from hard work, and all aviators know that safety is not an accident.
Even a glider can hurt you when you think the system is completely
safe.
David I. Luther
jgre...@xcor.com (Jeff Greason) wrote in message news:<9edf6d40.0208...@posting.google.com>...
Edward Wright
I'm not an auto mechanic, but I've always heard pinging referred to as
*predetonation* (meaning premature detonation).
See, for example, this web site:
http://www.curbsite.com/techforum/gasoline.html
> Engines where there is high compression need the resistance to burning so that the gasoline doesn't detonate
> before it is supposed to within the engine's cycle. When this does happen it is called predetonation
David Higgins
Edward Wright wrote:
>
> I'm not an auto mechanic, but I've always heard pinging referred to as
> *predetonation* (meaning premature detonation).
>
> See, for example, this web site:
> http://www.curbsite.com/techforum/gasoline.html
From what I've read, the curbside author has it wrong, but
I'm not going to get into a pissing match here. I did review
several websites to verify my understanding of detonation and
the gasoline engine. While doing that, I ran across this:
http://www.aardvark.co.nz/pjet/gokart.htm
Must be an interesting guy to have for a neighbor. :-)
To bring this slightly more on topic, this discussion resonates
with the "Did Challenger Explode?" threads that appear here from
time to time.
Now, like a good gearhead, I'm off the change the oil in one
of our Fleet-O-Junkers(tm).
John Williams
"Greg D. Moore (Strider)" wrote:
>
> And that's operating them at the limits of their performance. If I redlined
> my car every time I drove to the office I'd be happy if I didn't have
> problems after a few commutes.
Except that if you redlined your car everytime you drove it you would
expect to strip it down and rebuild pretty often, just like the SSMEs.
Let's at least compare red apples with green apples :)
Rgds,
John
Greg D. Moore (Strider)
"John Williams" <j2.wi...@qut.edu.au> wrote in message
news:3D698FAD...@qut.edu.au...
>
>
> "Greg D. Moore (Strider)" wrote:
> >
> > And that's operating them at the limits of their performance. If I
redlined
> > my car every time I drove to the office I'd be happy if I didn't have
> > problems after a few commutes.
>
> Except that if you redlined your car everytime you drove it you would
> expect to strip it down and rebuild pretty often, just like the SSMEs.
>
Umm, how is that an "Except" ? That was exactly my point.
Josh Hopkins
news:501f9880.02082...@posting.google.com...
> AFAIK the RD-107/108 engines on the R-7 derivatives have been very
> reliable. Does anyone have their actual statistics?
>
The root cause of some of the Soyuz failures have never been published
(AFAIK) so it's hard to draw any meaningful conclusions on engine
reliability.
In the early days there were several failures that must have been rather
spectacular in which one of the strap-on booster engines would shut down,
causing
the booster to rip off and the vehicle to be destroyed. However, in the
last thousand or so (!) launches I'm not aware of any failures which are
conclusively caused by the RD-107 or -108. There are a couple famous ones
in which the engine was distantly involved. The 1980 on pad explosion of a
Vostok at Plesetsk was caused by ground-system contamination of the hydrogen
peroxide supply for the main engines. It wasn't a main engine failure, but
one could argue that the characteristics of the engine (i.e. the need for
hydrogen peroxide in the first place) contributed to the failure. In 1966
there was an unusal failure in which the launch was aborted at the last
moment because of a failure of an oxidizer valve (come to think of it,
that's not necessarily part of the engine). The vehicle avionics were
apparently not shut down, and several minutes later, a different problem
casused
the crew escape system to fire, destroying the rocket. Again, I wouldn't
consider
this an engine failure, but one could argue that had the vehicle lifted off
as planned the
failure would never have happend.
Josh Hopkins
John Williams
> Umm, how is that an "Except" ? That was exactly my point.
Ah yes, so it was. You see, I got confused because this is usenet,
where we're supposed to take turns contradicting each other.
cheers,
John
Greg D. Moore (Strider)
No we're not.
Or yes we are.
Dang, now you've got me all confused.
>
> cheers,
>
> John
John Williams
"Greg D. Moore (Strider)" wrote:
>
> "John Williams" <j2.wi...@qut.edu.au> wrote in message
> news:3D6C6455...@qut.edu.au...
> > "Greg D. Moore (Strider)" wrote:
> >
> > > Umm, how is that an "Except" ? That was exactly my point.
> >
> > Ah yes, so it was. You see, I got confused because this is usenet,
> > where we're supposed to take turns contradicting each other.
>
> No we're not.
>
> Or yes we are.
>
> Dang, now you've got me all confused.
ah ha, mission accomplished!!
Bob Tenney
Simberg) wrote:
>On 23 Aug 2002 07:05:01 GMT, in a place far, far away,
>John.D...@comelec.enst.fr (John Doe) made the phosphor on my
>monitor glow in such a way as to indicate that:
>
>>> So even a vehicle that has to carry all of its own oxidizer will be less
>>> than twice the mass of one that doesn't.
>>
>>If you consider a hydrogen-oxygen chemical propulsion, you need about
>>16 tons of oxygen for every 2 tons of hydrogen, whatever the form you
>>store them in. Even if you don't save all the oxidizer by using an
>>airbreathing engine, it really could make a big difference on mass
>>(and hence liftoff thrust, structure, etc.)
>>
>>Or maybe you meant "size" or "volume"?
>
>I was referring to dry weight, which is one of the main parameters
>used for parametric costing, though GLOW is a factor as well.
>
But a jet engine of whatever flavor doesn't just pick up oxidizer en
route, it picks up most of it's reaction mass as well. After all the
exhaust is more heated nitogen than burn fuel. That's a lot of mass
you don't have to drag around before you need it.
Mail should spell my last name the way I do.
Gravity is "only a theory."
Edward Wright
>> I was referring to dry weight, which is one of the main parameters
>> used for parametric costing, though GLOW is a factor as well.
>
> But a jet engine of whatever flavor doesn't just pick up oxidizer en
> route, it picks up most of it's reaction mass as well. After all the
> exhaust is more heated nitogen than burn fuel. That's a lot of mass
> you don't have to drag around before you need it.
Correct. Instead, it's mass that you have to drag up from a low energy
state at the time you need it. TANSTAAFL.
How is that relevant to Rand's statement?
Bob Tenney
wrote:
>Correct. Instead, it's mass that you have to drag up from a low energy
>state at the time you need it. TANSTAAFL.
>
>How is that relevant to Rand's statement?
>
The gripping hand is: which takes more energy?
As to relevance, well it's partly just nit-picking but somehow eveyone
discussing rockets vs. jets always talks about oxidizer and never
reaction mass. It's a detail, but we all know who's in the details.
Tom Carman
>
> But a jet engine of whatever flavor doesn't just pick up oxidizer en
> route, it picks up most of it's reaction mass as well. After all the
> exhaust is more heated nitogen than burn fuel. That's a lot of mass
> you don't have to drag around before you need it.
In short, air-breathing engines are greatly favored for their efficiency
in applications where they have plenty of air to breathe. But as
someone once observed: "free" oxidizer and lift, like many other "free"
things, often aren't worth what you pay for them. If the application
calls for very high velocity, you want to be *out* of a high-drag,
high-heating environment like atmosphere ASAP. Tapping it for "free"
oxidizer during the short time you are in it really doesn't seem to be
worth the expense and effort required.
rschmitt23
engineer like myself who lived and worked through the hypersonic
disappointments of the 60s, 70s, 80s and 90s (I'm thinking of the Hypersonic
Ramjet Engine (HRE) program of the 1960s, the Transatmospheric Vehicle (TAV)
and Copper Canyon of late 1970s and 1980s and the National AeroSpace Plane
(X-30/NASP) of the late 1980s and 90s, all of which were technological
non-starters), it's good to see someone taking issue with the conventional
wisdom regarding the supposed benefits of airbreathing hypersonic
propulsion.
The X-30/NASP experience alone should be enough of a cautionary tale to
convince even the most ardent proponent of this long-desired Holy Grail of
aerospace technology, that scramjets, strutjets and other similar schemes
ain't going to happen for a very long time, if ever (see chapter 53 of my
book). The reason is simple: hypersonic airbreathing engine technology with
orbital capability (i.e. the scramjet) is super-expensive to develop (at
least $25B in today's money) and there is a viable, relatively low-cost
alternative (the rocket engine).
Funding for hypersonic research will undoubtedly continue at a low-level,
just to keep a nucleus of trained specialists busy, and we can expect to see
jumps in the budget every 10 or 15 years as a new generation of decision
makers decide to take another look at the technology. X/30-NASP was a
typical example of this cyclic behaviour and lasted about 8 years before the
Air Force and Congress decided that the supposed performance advantages of
the vehicle did not justify the $30B development cost for the orbital
version.
I expect that NASA's Space Launch Initiative (SLI) will take a whack at
hypersonic airbreathers before it fades into history in 2005 or 2006, once
they realize that their present work is based on the same myths and
fallacies that we used in the 1969-71 period to sell the initial space
shuttle to Congress and the Nixon White House.
Later
Ray Schmitt
Author: "U.S. Manned Spaceflight in the 20th Century: The Successes. The
Failures. The Options."
http://www.amazon.com/exec/obidos/ASIN/0972101004/qid%3D1030735175/sr%3D11-1
/ref%3Dsr%5F11%5F1/002-2150999-9328856
"Rand Simberg" <simberg.i...@trash.org> wrote in message
news:3d7e296e....@nntp.ix.netcom.com...
> Or, "We don't need no stinkin' scramjets."
>
> http://www.foxnews.com/story/0,2933,61066,00.html
GMW
performance of LOX/Kerosene engines could yield impressive savings in fuel
and oxidizer. Even better, a 15% performance enhancement would clear the
deck for a viable SSTO.
What are the issues involved in getting these performance enhancements? Are
current engines good enough or can they be made better?
Edward Wright
>>Correct. Instead, it's mass that you have to drag up from a low
energy
>>state at the time you need it. TANSTAAFL.
>>
>>How is that relevant to Rand's statement?
>>
> The gripping hand is: which takes more energy?
That's easy. A rocket will take much less energy to reach orbit,
because it has less drag. (Repeat after me: "We don't need no stinking
inlets." :-)
Your statement is wrong, however. The gripping hand is not energy. It
is *money*. Don't tell me about ergs, talk to me about dollars.
I tell you this three times: Money is *valuable*!
Jon Berndt
>
> I expect that NASA's Space Launch Initiative (SLI) will take a whack at
> hypersonic airbreathers before it fades into history in 2005 or 2006,
I haven't seen any indications that this is being seriously considered. Do
you have any evidence to support this expectation?
Jon
Christopher M. Jones
I said that. It comes from the rocket equation, mass
ratio (propellant plus dry mass to dry mass) scales
exponentially with the ratio of delta V to rocket
exhaust velocity. Tt takes roughly 9 km/s to get to
orbit, and modern LOX/Kerosene engines (RD-180) have an
exhaust velocity of 3.1 km/s, so a rocket with an RD-180
has to have a mass ratio of about 18:1 to get to orbit.
Or, in other words, it has to have a dry mass fraction
of ~0.055. Since a rocket has its own dry mass fraction
(structure, engine mass, etc.) it has a maximum delta V.
Or, in other words, if the dry mass fraction of the
rocket is higher than the dry mass fraction (inverse of
the mass ratio) needed to get to a certain destination
(e.g. orbit) with a specific engine then the rocket will
not be able to reach that destination nor deliver payload
to it. For example, as mentioned above it takes a dry
mass fraction of 0.055 or below to get to orbit on a
single stage with an RD-180 (LOX/Kero). To put that in
perspective, the Saturn V first stage had a dry mass
fraction of 0.059, and the Atlas V core has a dry mass
fraction of 0.073 (both LOX/Kero stages). Improving
LOX/Kero Isp by 5% raises the dry mass fraction to reach
orbit to 0.086, 10% to 0.097, 15% to 0.11. So you can
see how close the "SSTO line" is to current capabilities
(very close).
The biggest problem is that for the most part high-thrust
rocket engine development in the US has been dead or nearly
so for several decades. With only a few exceptions mostly
in LH2/LOX engines (like the SSMEs). The only people that
have been working seriously on LOX/Kerosene engines in the
last 3 decades have been the Russians. And, for various
reasons (partly the Russian economy, partly the politics of
launch vehicles) we most likely won't see a lot of really big
development in that area for a while.
If you really want an RLV SSTO then the most sensible route
is to meet somewhere in the middle, with better engines and
lighter structures, but not so much so that you are on the
bleeding edge of technology in any one area. Composite
tanks for LOX and Kerosene are possible and not terribly
difficult if they are standard shapes (cylindrical) and not
the "conformally shaped" kind they tried to build for X-33.
Lighter structural designs are also possible (witness the
light weight Shuttle ETs). Improved LOX/Kero rocket
performance is also possible and fairly easily achievable
with a moderate amount of R&D. The best current LOX/Kero
engines were developed by the Russians mostly in the 1980s.
Today in the west we have better materials and we are better
able to design and simulate systems in computers. That,
plus a hefty chunk of change, should be enough to eek out
some decent performance gains in LOX/Kero engines.
Despite the abyssmal shape of basic launch vehicle R&D over
the last few decades we still have all the technological
pieces on the table for cheap access to space and nearly all
the pieces for reliable, economical SSTO RLVs.
--
Error, unmatched '{' in script
rschmitt23
Just a gut feeling, based on 37 years in or around the aerospace business.
NASP collapsed in 1994, so I expect, based on the previous cyclic history
of this type of activity, that hypersonic airbreathers will be due for
another major go-round in the 2005 timeframe.
Somewhat depends on the faltering X-43 Hyper-X program. If NASA fails to
work the kinks out of that stumbling effort, hypersonic airbreathing engine
technology development may fall into a really long slumber (see chapter 53
of my book for more details).
Ray Schmitt
"Jon Berndt" <a@b.c> wrote in message news:akou77$1ugq$1...@news.hal-pc.org...
Len
> > and when designed with safety as a design constraint, can be
> > quite reasonable in their failure modes and effects.
>
> have flown, what is it, now, about 112 missions? That's 336 main engine
> "cycles" flown over roughly twenty years. IIRC there have been only two
> in-flight shutdowns, and I believe they were not even due to real engine
> problems, but sensor faults. The SSMEs are also at the higher end of the
> number of flights they have worked flawlessly if I am not mistaken. I'm not
> an expert on the history of the early jet engine, but what was their safety
> record early on?
>
> Jon
I flew the FJ-1 (straight-wing, Navy version of the F-86).
The time between overhauls on the jet engine was 20 hours.
Single builds of the RL10 have been started several hundred
times without failure. IIRC, the wear and tear parts like the
turbopumps have run about five hours without getting out of
tolerance and without an oil system--even though it is
supposed to be an expendable engine. Until the "system
engineering" failure of one of the Atlases (not, strictly
speaking, an engine failure, but a propellant feed/interface
failure), the RL10 had never failed in flight. As I posted
earlier, a scramjet has far greater regen-cooled area per
unit of thrust.
I understand that they really don't know how long the RD-0124
will run--the tank car ran dry after eight hours during a
duration test.
You and I and Jeff and a lot of others agree that so-called
safety and maintenance drawbacks of rocket engines are a bum
rap. NASA should be working on things like extending
the time between overhaul on these basically simple engines.
Jon Berndt
> Jon:
>
> Just a gut feeling, based on 37 years in or around the aerospace business.
> NASP collapsed in 1994, so I expect, based on the previous cyclic history
> of this type of activity, that hypersonic airbreathers will be due for
> another major go-round in the 2005 timeframe.
Have you seen this:
http://www.slinews.com/concepts.html
None of these concepts features anything other than standard rocket engines.
However, for the follow-on third-generation RLV my gut feeling is that your
gut feeling is correct. :-) I suspect that hypersonic airbreathers will get
yet another look.
Jon
Edward Wright
>> I expect that NASA's Space Launch Initiative (SLI) will take a
whack at
>> hypersonic airbreathers before it fades into history in 2005 or
2006,
>
> I haven't seen any indications that this is being seriously considered. Do
> you have any evidence to support this expectation?
It's been part of SLI from the beginning. NASA calls it "Third
Generation RLV."
Some of my sources say there's a faction at Marshall that wants to
"skip a generation" and go straight to the airbreathers because only a
"quantum leap" will gain the performance they need. Never mind that
rockets had sufficient performance to reach orbit in the 1960's.
This approach has the advantage that it would require more research up
front, and thus take several more years to fail. :-)
Christopher M. Jones
> For example, as mentioned above it takes a dry
> mass fraction of 0.055 or below to get to orbit on a
> single stage with an RD-180 (LOX/Kero). To put that in
> perspective, the Saturn V first stage had a dry mass
> fraction of 0.059, and the Atlas V core has a dry mass
> fraction of 0.073 (both LOX/Kero stages). Improving
> LOX/Kero Isp by 5% raises the dry mass fraction to reach
> orbit to 0.086, 10% to 0.097, 15% to 0.11. So you can
> see how close the "SSTO line" is to current capabilities
> (very close).
Oops!
Dangit, rushed out the post too quickly, quick corrections:
the Isp / dry mass fractions should be 0% improvement to
0.055, 5% to 0.063, 10% to 0.071, 15% to 0.080.
Plus, a quick followup on some stuff I forgot to mention.
The reason why LOX/Kerosene is preferable to LOX/LH2 is
because it generates more thrust (and is thus easier to
design an all liquid fueled rocket that lifts off the
ground without booster rockets) and it is denser.
LOX/LH2 has a lot higher exhaust velocity (up to 4.5 km/s)
but LOX/LH2 stages have a lot higher dry mass fractions.
Plus, an all LOX/LH2 first stage has to sacrifice a lot
of Isp / exhaust velocity in order to generate enough
thrust to get off the ground on it's own. For example,
the LOX/LH2 engines for the Shuttle and the Delta IV have
a sea level exhaust velocity of only 3.6 km/s. Which
would put the "SSTO dry mass fraction" at 0.082. However,
current LOX/LH2 stages have a dry mass fraction of 0.12.
Which means that LOX/LH2 SSTOs are a lot "farther away"
than LOX/Kero SSTOs. Current LOX/Kero engines and stages
are "there" in terms of SSTO possibility. LOX/LH2 SSTOs
*would* require new engines, new techniques and materials
for building tanks and structures, and a whole host of
new googahs. Just as it would take a heck of a lot of
bleeding edge engineering to race an electric car in
NASCAR. But we already have technology on the shelf that
is good enough for cheap launch and is very, very close
to being good enough for SSTO. 1-2% improvement in dry
mass fraction plus 1-2% improvement in engine performance
and *poof* SSTO.
--
Everyone says to use your powers for good, but that's no fun!
Jon Berndt
> It's been part of SLI from the beginning. NASA calls it "Third
> Generation RLV."
No. There is loose talk of a third generation vehicle, but that's not part
of SLI. You might want to have a look at this page to learn more about SLI,
yourself:
http://www.slinews.com/SLI1.html
> Some of my sources say there's a faction at Marshall that wants to
> "skip a generation" and go straight to the airbreathers because only a
> "quantum leap" will gain the performance they need.
I think this is one of those ideas that's not going to percolate to the top
at this time ...
Jon
Jeff Greason
> I flew the FJ-1 (straight-wing, Navy version of the F-86).
> The time between overhauls on the jet engine was 20 hours.
> Single builds of the RL10 have been started several hundred
> times without failure.
Just to further emphasize Len's point.
Because of the high thrust and high propellant flowrate
for rocket engines, rocket vehicles inherently fly
"accelerator" class missions, with a boost-coast or
boost-glide trajectory. As a result, a rocket mission
might have 2-8 minutes of engine burn for one complete
mission, and the mission duration might run from tens
of minutes to tens of years. In other words, the duty
cycle of engine operation time divided by total mission
time is low.
Because of the comparatively low thrust, limited top
speed and altitude, and low propellant flowrate of
airbreathing engines, they inherently fly "cruise"
class missions (although there are programs from time
to time which accelerate with airbreathers). As a
result, the overwhelming majority of airbreathing
engines are running throughout the flight duration.
In other words, 100% duty cycle -- if your plane
is in the air for 8 hours, your engine runs for
8 hours.
As a result, if rockets are developed which have life
of thousands of cycles, that's the same useful
mission performance as a jet engine with tens of
thousands of hours of useful life.
----------------------------------------------------------------
"Limited funds are a blessing, not Jeff Greason
a curse. Nothing encourages creative President & Eng. Mgr
Jim Kingdon
> km/s
Well, and doing better than that (359 s vacuum which I calculate to be
3.51 km/s) has been demonstrated on the RD-0124 (the upper stage for
Soyuz FG).
rschmitt23
"Jon Berndt" <a@b.c> wrote in message news:akpigd$28ee$1...@news.hal-pc.org...
> Have you seen this:
>
> http://www.slinews.com/concepts.html
Jon:m
Thanks for the input. Yes, I saw that webpage previously, and, as Yogi says,
it was deja vu all over again. You're absolutely correct: SLI, right now,
is only considering options with conventional bell nozzle engines. However,
all of these ideas have been considered before in Phases A and B of the
original shuttle effort in 1969-71. You can find the details in Richard
Hallion's massive work entitled "The Hypersonic Revolution" (1987). Dick
Hallion is the USAF Chief Historian.
SLI undoubtedly will come up with the same cost numbers for development and
operation of their RLV designs that we did in 1970-71 (in constant dollars,
say $Y2K). The reason is simple: Today's launch vehicle technology that the
SLI guys and gals are trading off is essentially the same technology that we
had in the 1970 timeframe. There have been no wonder propellants or super
materials discovered in the last 30 years that would change any of
this.Every so-called advance in launch vehicle technology (e.g. the SSME
with its 3000-psi staged combustion powerhead, SSME improvements like the
Pratt & Whitney turbopumps, aluminum-lithium LOX tanks, graphite-epoxy
composite LH2 tanks, etc) represents an incremental change, not the quantum
leap that would lead to factors of two or more reduction in launch
operations costs (see Chapter 44 of my book for more details).
That's why I think the SLI group is going to hit a brick wall in the next
two years and, to keep the effort alive, will start to look at 3rd
generation concepts like the scramjet and strutjet. However, I don't think
that they will be able to change the NASP cost numbers or the 15-20 year
development schedule. A full-size shuttle replacement using scramjet
technology is still the same $30B development effort today as it was in
1990 during NASP's heyday.
FYI: I'm really disturbed by the priorities that NASA has now. I think it's
a crying shame that the X-38 is stalled (more likely, dead) while billions
are being spent uselessly on the SLI stuff. The U.S. manned spaceflight
effort would be much better served by getting the X-38/CRV development on
the fast track to end the really embarrasing mess that we have now with the
ISS crew limitation problem. The X-38/CRV, a SMALL, REUSABLE CREW
RETURN/ROTATION VEHICLE, is precisely where it makes sense to develop
reusable space vehicle hardware. Trying to develop cost effective REUSABLE
LAUNCH VEHICLE HARDWARE, the aim of the SLI, is an exercise in futility, as
we learned from our sorrowful 30-year experience with the current TAOS space
shuttle configuration (again see Chapter 44 of my book for details).
Oops. You seem to have pressed one of my hot buttons.
Later
Ray Schmitt
Author: "U.S. Manned Spaceflight in the 20th Century: The Successes. The
Failures. The Options."
http://www.amazon.com/exec/obidos/ASIN/0972101004/qid%3D1030843435/sr%3D11-1
/ref%3Dsr%5F11%5F1/002-2150999-9328856
John Carmack
>The reason why LOX/Kerosene is preferable to LOX/LH2 is because it
generates
>more thrust
As I understand it, for a given sized nozzle, a hydrogen engine
doesn't generate any less thrust than any other engine propellent.
The only place you lose thrust to weight on the engine is in the
turbopumps, which are sized based on volume flow, so must be much
larger to pump a given mass flow.
Except for minor differences due to the isentropic parameter, a nozzle
with a given chamber pressure will make basically the same thrust
whether the chamber holds atomic hydrogen or mercury vapor. The
mercury vapor would just toss away mass a whole lot faster to generate
that thrust.
>Plus, an all LOX/LH2 first stage has to sacrifice a lot of Isp /
exhaust
>velocity in order to generate enough thrust to get off the ground on
it's
>own. For example, the LOX/LH2 engines for the Shuttle and the Delta
IV have
>a sea level exhaust velocity of only 3.6 km/s.
Sea level Isp is lower due to the existence of atmospheric pressure,
not because of any tuning to increase thrust.
Note that I am not defending hydrogen in any way, being a
peroxide-kerosene fellow, just clarifying the issues.
John Carmack
www.armadilloaerospace.com
day...@ieee.org
row exploded on the launch pad. Remember the 1950's? Commercial jet
engines and rocket engines are now reliable because of the extensive amount
of effort put in to make them reliable. Arguments about whether jets or
rockets or scramjets are "more reliable" are just off-mark. At one time we
thought astronauts were heroes and daredevils because rockets were thought
to be so unreliable. Comparing a mature technology with and infant
technology is just not valid, and perhaps a bit Luddite in nature.
The SSMEs are not acceptably reliable by commercial standards, and probably
don't meet the man-rating requirements of the old Apollo programs. Look at
the history of in-flight shutdowns, and look at the maintenance history.
Those engines require extensive refurbishment between every flight. Does
someone know how much NASA is currently spending (and more interesting,
should be spending) to turn a shuttle around?
You can't fly to orbit with a scramjet. Even at hypersonic speeds usable
oxygen practically disappears above 150,000 feet. Of course, you could
cheat, and start carting around a little oxidizer like tetraethyl borane in
same way the SR-71 does, but that's not the point of this discussion.
Example: at 20,000 m at Mach 1 (~65,000 feet), oxygen flow rate is about 10
kg/m^s. That's plenty for current air breathing engines. To get that same
flow rate at 47,000 m (150,000 feet), you need to go Mach 59. You can play
games such as use variable geometry inlets.
Does this mean scramjets are not usable for transportation to space? Not at
all. If the engine is really as simple as strapping a sewer pipe on the
side of an existing booster, a scramjet could provide significant thrust
augmentation. Assertions about high drag and instability don't make sense
to me. An open tube has less drag than close cylinder. A scramjet with a
closed inlet spike will present no more parasitic drag than a nose cone.
Staibility is a characteristic of the vehicle, not the engine.
If the discussion is about a monopolistic space agency diverting resources
to research scramjets, then perhaps scramjets aren't worth it. If instead,
many competing organizations exist, then perhaps one of them will try to
build the better mouse trap and try scramjets to gain a competive edge for
launch services. Considering the number of countries and commercial
agencies providing launch services, it would not surprise me to see scramjet
thrust augmentation within 10 years.
The basics:
-- a rocket accelerates its fuel and oxidizer to get thrust.
-- a scramjet accelerate its fuel, oxidizer, and working medium to get
thrust.
-- a rocket carries its oxidizer, and must accelerate that consumable
-- a scramjet extracts its oxidizer from the working medium.
--
Glen Dayton day...@ieee.org
"Len" <l...@tour2space.com> wrote in message
news:36dabe8a.02083...@posting.google.com...
Edward Wright
> No. There is loose talk of a third generation vehicle, but that's not part
> of SLI. You might want to have a look at this page to learn more about SLI,
> yourself:
>
> http://www.slinews.com/SLI1.html
You need to read more than that one page.
3rd Generation RLV received $111 million in FY 02 and is requesting
$120 million in FY 03. NASA is funding the development of at least two
Rocket-Based Combined Cycle engines and is currently pressing ahead
with plans for X-43C.
Edward Wright
> SLI undoubtedly will come up with the same cost numbers for development and
> operation of their RLV designs that we did in 1970-71 (in constant dollars,
> say $Y2K). The reason is simple: Today's launch vehicle technology that the
> SLI guys and gals are trading off is essentially the same technology that we
> had in the 1970 timeframe. There have been no wonder propellants or super
> materials discovered in the last 30 years that would change any of
> this.
On caveat here. It makes a huge difference once organization is doing
the project. I remember a few years ago, an engineer was asking how
much it would cost to build the DC-Y. He replied something like, "$500
million if it were a private company doing it, a billion if DARPA or
SDIO does it under streamlined management, $5 billion if it's a
standard Air Force contract, and $20 billion if NASA does it.
Materials have made some advances in the last 30 years, although those
advances have not really affected the space sector. However, that is
mostly irrelevant. The price of materials and propellants is only a
minor cost driver in space transportation at present. Unfortunately,
NASA is caught up in the mindset similar to the 1960's spy thrillers,
where everyone is pursuing the secret formula for rocket fuel that
will open space. In reality, there is no secret formula.
> The U.S. manned spaceflight effort would be much better served by getting the X-38/CRV development on
> the fast track to end the really embarrasing mess that we have now with the
> ISS crew limitation problem.
You might change your mind if you heard what Burt Rutan said about
X-38 at Oshkosh last year. "You'd have to be pretty sick to ride in
it." BTW, the numbers I've seen indicate that X-38 is badly over
budget.
Rand Simberg
edwrig...@hotmail.com (Edward Wright) made the phosphor on my
monitor glow in such a way as to indicate that:
> In reality, there is no secret formula.
Actually, there is. It's so secret that few at NASA understand it.
It's called "market."
rschmitt23
>
> On caveat here. It makes a huge difference once organization is doing
> the project. I remember a few years ago, an engineer was asking how
> much it would cost to build the DC-Y. He replied something like, "$500
> million if it were a private company doing it, a billion if DARPA or
> SDIO does it under streamlined management, $5 billion if it's a
> standard Air Force contract, and $20 billion if NASA does it.
>
I hope that you are not suggesting that NASA is some kind of blundering
organization of idiots and incompetents. Today, in the early 21st century,
that kind of NASA-bashing is becoming tedious and worn out. I worked on the
DC-X/XA/Y and the X-33 programs at McDonnell Douglas and, while I can image
one or two of my colleagues making that kind of remark, I don't think that
kind of simple mindedness was prevalent there. And the vast majority of the
NASA folks that I encountered in my 32 years in the aerospace business were
every bit as professional and competent as their counterparts in the prime
contractor organizations.
However, I also know that NASA-bashing continues to be a popular pasttime,
especially among some of the advocates of various SSTO launch vehicle
schemes. I came into contact with many of these folks during the DC-X/XA
days, and, I regret to say, that I detected a definite odor of elitism in
that group. The attitude is that NASA incompetence had tied the shuttle up
in a mountain of red tape with its tedious Flight Readiness Review (FRR)
process and all the other paperwork that floats around that system. The
argument is that an shuttle-size SSTO, operated by a small group of
super-competent individuals, would not require all the operating expense
associated with NASA shuttle red tape. The result would be shuttle-size
SSTO launch vehicles with airline-type operational cost. This is grade-A BS.
Any would-be SSTO replacement for the shuttle would have the same operating
costs, simply because today's technology, that would be used by that SSTO,
is the same as that used 30 years ago for the original shuttle. The red tape
is there primarily to ensure misison success and astronaut safety.
Neglecting procedures and cutting corners caused the Challenger loss and, by
NASA's own estimates, a $13B ($Y2K) cost impact (see chapters 45 and 55 of
my book). No privately financed SSTO shuttle replacement could get flight
insurance unless the pre-flighting of that vehicle were at least as thorough
and detailed as NASA's shuttle flight recertification process. Again, the
reason is the enormous financial impact of a Challenger-like failure.
As far as the cost effectiveness of building DC-Y's in a private company, I
have only a few words to say: "X-33" and "Skunk Works".
>
> > The U.S. manned spaceflight effort would be much better served by
getting the X-38/CRV development on
> > the fast track to end the really embarrasing mess that we have now with
the
> > ISS crew limitation problem.
>
> You might change your mind if you heard what Burt Rutan said about
> X-38 at Oshkosh last year. "You'd have to be pretty sick to ride in
> it." BTW, the numbers I've seen indicate that X-38 is badly over
> budget.
Burt is probably referring to the well-known history of lifting bodies with
their high landing speeds and the various aerodynamic instability modes that
can afflict these vehicles. It's very likely that some of the lifting body
pilots thought the same about Rutan's Voyager aircraft. Beauty (and risk) is
in the eye of the beholder. See Dale Reed's excellent first hand account of
the early days of lifting body flight research in his "Wingless Flight: The
Lifting Body Story" (1997, NASA SP-4220).
I'm quite a bit more optimistic than Rutan since the X-38 is derived from
the Martin X-24A lifting body of the late 1960s and early 1970s. The X-24A,
in turn, was derived from the SV-5B/PRIME vehicle that made three very
successful sub-orbital flights to Mach 23. The 3rd SV-5B flight vehicle
demonstrated about 710 n. mi. of cross-range capability and its parachute
was snagged by the C-130 recovery plane about 5 n. mi from the target. That
vehicle now resides in the Air Force Museum. That flight occurred on 19
April 1967 (see chapter 23 of my book). So we've known for a long time that
the basic X-38 configuration operates very well in the hypersonic reentry
regime. In addition, the piloted X-24A made 19 powered flights between
April 1969 and June 1971 without difficulty, reaching 1,036 miles per hour
(roughly Mach 1.4) and 71,100 feet altitude. Once again, we've known for a
long time that the X-38 configuration has good subsonic and supersonic
handling characteristics. Consider that the shuttle orbiter Approach and
Landing Tests (ALT) covered a much smaller flight regime (speed less that
500 mph, altitude about 35,000 feet). And it looks like NASA is making good
progress working out the kinks in the X-38 parasail recovery system.
Later
Ray Schmitt
Author: "U.S. Manned Spaceflight in the 20th Century: The Successes. The
Failures. The Options."
http://www.amazon.com/exec/obidos/ASIN/0972101004/qid%3D1030935498/sr%3D11-1
/ref%3Dsr%5F11%5F1/002-2150999-9328856
Edward Wright
> The RL-10 had a lengthy development period. Something like 7 Atlases in a
> row exploded on the launch pad.
If that's true, it was obviously not the RL-10 that was at fault. The
RL-10 is the Centaur upper stage engine. It was never used on the
Atlas first stage. The only time I can recall it being used as a
first-stage engine was on the DC-X.
> Of course, you could
> cheat, and start carting around a little oxidizer like tetraethyl borane in
> same way the SR-71 does,
The SR-71 uses triethyl borane not as an oxydizer but as a catalytic
ignitor For details, see the flight manual:
http://www.sr-71.org/blackbird/manual/1/1-22.htm
> If the engine is really as simple as strapping a sewer pipe on the
> side of an existing booster, a scramjet could provide significant thrust
> augmentation.
Well, if the scramjet really is as simple as a sewer pipe, someone
should refund the taxpayers a few billion dollars. :-)
Rand Simberg
"rschmitt23" <rschm...@cox.net> made the phosphor on my monitor glow
in such a way as to indicate that:
>As far as the cost effectiveness of building DC-Y's in a private company, I
>have only a few words to say: "X-33" and "Skunk Works".
To call Lockmart a "private company" is to stretch the meaning of the
term beyond any useful definition. The last commercial venture by
this "private company" was the Tri-Star. We all know how well that
worked out...
Mark Bradford
> I hope that you are not suggesting that NASA is some kind of blundering
> organization of idiots and incompetents.
I don't think anyone would suggest that; however, NASA *is* a ponderous
organization laden with managers and bureaucrats (in addition to large
numbers of professional and competent engineers and scientists).
> Any would-be SSTO replacement for the shuttle would have the same operating
> costs, simply because today's technology, that would be used by that SSTO,
> is the same as that used 30 years ago for the original shuttle.
This, I think, is entirely mistaken, both in stating that an SSTO
replacement would use the same technology as the shuttle (*I* certainly
wouldn't make the same choices as NASA) and that it would have the same
operating costs (the costs of operating the Shuttle are mostly manpower,
and are largely independent of whether or not the thing actually
flies!).
> The red tape
> is there primarily to ensure misison success and astronaut safety.
Except that there is little evidence that it actually does so. Henry
Spencer likes to point out that when an assembly platform got left in
the Shuttle bay (*CLUNK* "What was THAT?!"), three signatures said it
had been removed.
--
Mark Bradford <t...@surly.org>
"It is good to have an open mind, but not at both ends."
Andrew Case
>rschmitt23 wrote:
>
>> I hope that you are not suggesting that NASA is some kind of blundering
>> organization of idiots and incompetents.
>
>I don't think anyone would suggest that; however, NASA *is* a ponderous
>organization laden with managers and bureaucrats (in addition to large
>numbers of professional and competent engineers and scientists).
Including large numbers of smart, competent people responding to the
perverse incentives created by pork barrel politics. When failures
(which are inevitable in any sufficiently ambitious research program)
lead to calls for resignation and to congressional hearings, an irrational
caution starts to creep in, along with a CYA attitude.
>> Any would-be SSTO replacement for the shuttle would have the same operating
>> costs, simply because today's technology, that would be used by that SSTO,
>> is the same as that used 30 years ago for the original shuttle.
>
>This, I think, is entirely mistaken, both in stating that an SSTO
>replacement would use the same technology as the shuttle...
[...]
An SSTO designed for low ops costs could easily achieve dramatic savings
over shuttle, which was designed in response to an interconnected web of
bizarre and contradictory requirements, many having nothing to do with
spaceflight, and the most important ones (related to pork) never written
down or publicly expressed. Ed Wright likes to say that the primary
mission of shuttle is to employ some 30,000 people, and he's got a good
point.
......Andrew
--
--
Andrew Case |
ac...@plasma.umd.edu |
Michael Walsh
Rand Simberg wrote:
> On Mon, 02 Sep 2002 03:09:12 GMT, in a place far, far away,
> "rschmitt23" <rschm...@cox.net> made the phosphor on my monitor glow
> in such a way as to indicate that:
>
> >As far as the cost effectiveness of building DC-Y's in a private company, I
> >have only a few words to say: "X-33" and "Skunk Works".
>
> To call Lockmart a "private company" is to stretch the meaning of the
> term beyond any useful definition. The last commercial venture by
> this "private company" was the Tri-Star. We all know how well that
> worked out...
Playing a funny definition game?
Lockheed-Martin is certainly a private company, owned by its stockholders.
It is an aerospace company with most of its business as a government
contractor.
Mike Walsh
rschmitt23
"Mark Bradford" <t...@surly.org> wrote in message
news:slrnan722...@surly.org...
>
> I don't think anyone would suggest that; however, NASA *is* a ponderous
> organization laden with managers and bureaucrats (in addition to large
> numbers of professional and competent engineers and scientists).
>
Thanks for your input. From my experience with NASA over three decades, the
NASA managers manage as well as or better than the prime contractor
managers. As for bureaucrats, well you have to be living in a cave not to
realize that bureaucracy exists in every human organization large and small,
including aerospace prime contractors. Savvy managers inside NASA and the
prime contractor organizations know how to use the bureaucracy to get done
what needs to be done (e.g. Kelly Johnson's Skunk Works, the von
Braun/Medaris organization that launched Explorer I, the ASSET and PRIME
organizations, Paul Klevatt's DC-X/XA group, etc. etc.).
> This, I think, is entirely mistaken, both in stating that an SSTO
> replacement would use the same technology as the shuttle (*I* certainly
> wouldn't make the same choices as NASA) and that it would have the same
> operating costs (the costs of operating the Shuttle are mostly manpower,
> and are largely independent of whether or not the thing actually
> flies!).
>
Flash! Today's technology is the same as the 1970s variety used in the
original shuttle. I know this for a fact. I worked for four years on
shuttle TPS from 1968 through 1972 and then on X-33 TPS from 1995-96. The
TPS technology is the same, the structures and propellant tank technologies
are the same. The liquid rocket engine technology is the same. And the
software development technology is the same. The only difference now is that
the flight computer hardware of the next generation shuttle replacement will
be greatly improved over the 1970s IBM 370 technology used in the original
shuttle. But this represents a miniscule part of the cost. Flight software
development and verification and validation (V&V) is still as tedious and
expensive today as it was in the 1970s. Witness Boeing's struggle with the
ISS software development and V&V effort in the late 1990s, continuing to the
present.
The development and operating costs and the operating risks associated with
the next generation shuttle replacement will be the same as those of the
present shuttle, BECAUSE THE TECHNOLOGY IS THE SAME. Write these words on a
piece of paper, tape it to your bathroom mirror and repeat the words ten
times each morning while you shave and/or take care of those annoying skin
blemishes that lately have put a crimp in your social life.
Your point about manpower being the major shuttle operating cost is an old
and well known fact. A.O Tischler, Head of the Chemical Propulsion Division
of NASA's Office of Advanced Research and Technology, said the same thing in
early 1969. In 1984 James Beggs, the then NASA Administrator, testified
before a House subcommittee concerning the "standing army" that is necessary
to operate the shuttle organization. Dan Goldin said essentially the same
thing numerous times during the 1990s as he shuffled the deck and tried to
find some way to reduce the headcount by off-loading shuttle flight
re-certification work to the USA organization and to other contractors (see
chapter 44 of my book).
The point is that nobody has been able to change this during the last 30
years. And despite what we at McDonnell Douglas said in the DC-X/XA/Y sales
brochures of the 1990-96 period, it is unlikely that anything the SSTO
proponents or the SLI guys and gals come up with will change the need for
the standing army. The technology is the same and the economic impact of a
launch failure is far too high to cut corners here (NASA testified that the
economic impact of Challenger was $13B in $Y2K, which, coincidentally, is
equal to NASA's average annual budget in the shuttle era).
> > The red tape
> > is there primarily to ensure misison success and astronaut safety.
>
> Except that there is little evidence that it actually does so. Henry
> Spencer likes to point out that when an assembly platform got left in
> the Shuttle bay (*CLUNK* "What was THAT?!"), three signatures said it
> had been removed.
>
Yes, all of us have heard these horror stories before. This is one of John
Madden's "left foot, right foot" situations. For every anecdote like that,
one or more counter examples can be cited to show the opposite, i.e. that
the red tape promotes safety.
I don't recall that a shuttle flight was actually launched with a large
piece of GSE inadvertently left in the payload bay. Someone in the shuttle
organization apparently makes sure this type of screwup doesn't happen.
Probably someone in the standing army.
Later
Ray Schmitt
Author: "U.S. Manned Spaceflight in the 20th Century: The Successes. The
Failures. The Options."
http://www.amazon.com/exec/obidos/ASIN/0972101004/qid%3D1030993434/sr%3D11-1
/ref%3Dsr%5F11%5F1/002-2150999-9328856
Rand Simberg
Walsh <mp1w...@Adelphia.net> made the phosphor on my monitor glow in
such a way as to indicate that:
>> To call Lockmart a "private company" is to stretch the meaning of the
>> term beyond any useful definition. The last commercial venture by
>> this "private company" was the Tri-Star. We all know how well that
>> worked out...
>
>Playing a funny definition game?
>
>Lockheed-Martin is certainly a private company, owned by its stockholders.
>
>It is an aerospace company with most of its business as a government
>contractor.
Well, if that's your criteria, it's actually a public company. But my
point is that they don't do commercial work, and there's no reason to
think that they know how to do things either quickly or cheaply.
Rand Simberg
"rschmitt23" <rschm...@cox.net> made the phosphor on my monitor glow
in such a way as to indicate that:
>Thanks for your input. From my experience with NASA over three decades, the
>NASA managers manage as well as or better than the prime contractor
>managers.
I don't think anyone was commending them, either. The difference
isn't between NASA and its contractors--it's between the
NASA/contractor community, and commercial companies.
Scott Lowther
>
> On Mon, 02 Sep 2002 19:15:15 GMT, in a place far, far away,
> "rschmitt23" <rschm...@cox.net> made the phosphor on my monitor glow
> in such a way as to indicate that:
>
> >Thanks for your input. From my experience with NASA over three decades, the
> >NASA managers manage as well as or better than the prime contractor
> >managers.
>
> I don't think anyone was commending them, either. The difference
> isn't between NASA and its contractors--it's between the
> NASA/contractor community, and commercial companies.
Note that companies that do business with the government have to have
little "microclimates" within their company based on who they're dealing
with. At my company, we have the NASA manned stuff, which means months
of red tape; the DoD stuff, which means weeks of red tape and IR&D,
which means hours of red tape, if any at all.
--
Scott Lowther, Engineer
Kevin Willoughby
>
> I hope that you are not suggesting that NASA is some kind of blundering
> organization of idiots and incompetents.
Hardly. What contact I've had with NASA people, and what I've read in
various places makes clear there are a *lot* of talented, dedicated and
intelligent people. It isn't so much a question of no good people, but
a way of doing business that is big, slow and labor-intensive.
> The attitude is that NASA incompetence had tied the shuttle up
> in a mountain of red tape with its tedious Flight Readiness Review (FRR)
> process and all the other paperwork that floats around that system.
Given what the Shuttle is, a lot of paperwork is a necessity. No one
criticises NASA for wanting to avoid another Challenger or Apollo 1
disaster.
A spacecraft designed from scratch to minimize operation costs would be
able to fly with less paperwork than the Shuttle. Perhaps that should
have been the goal of Shuttle, but it wasn't. (The new Atlas V may
represent an example of this -- it is supposed to be built quickly and
spend less than a day on the pad. Time will tell if they've succeed,
but the goals are right.)
--
Kevin Willoughby kevinwi...@scispace.org.invalid
Microsoft treats security vulnerabilities as
public relations problems. -- Bruce Schneier
Mark Bradford
> "Mark Bradford" <t...@surly.org> wrote in message
> news:slrnan722...@surly.org...
>> This, I think, is entirely mistaken, both in stating that an SSTO
>> replacement would use the same technology as the shuttle (*I*
>> certainly wouldn't make the same choices as NASA) and that it would
>> have the same operating costs (the costs of operating the Shuttle are
>> mostly manpower, and are largely independent of whether or not the
>> thing actually flies!).
> The development and operating costs and the operating risks associated
> with the next generation shuttle replacement will be the same as those
> of the present shuttle, BECAUSE THE TECHNOLOGY IS THE SAME. Write
> these words on a piece of paper, tape it to your bathroom mirror and
> repeat the words ten times each morning while you shave and/or take
> care of those annoying skin blemishes that lately have put a crimp in
> your social life.
Um, no, because *I don't believe it*. I'm not asserting that major
savings in costs and increased capability will arise from miraculous new
technological advances. I'm saying that making different choices,
*using the same level of technology* (but different specific
technologies, such as avoiding staged combustion, sticking with kerosene
over LH2, over-engineering the vehicle and not running it at the edge of
the envelope, or other methods to simplify maintenance) would likely
result in reduced operating costs and risks.
A fresh-start SSTO would not be obligated to re-invent the Shuttle as it
exists.
> The point is that nobody has been able to change this during the last
> 30 years. And despite what we at McDonnell Douglas said in the
> DC-X/XA/Y sales brochures of the 1990-96 period, it is unlikely that
> anything the SSTO proponents or the SLI guys and gals come up with
> will change the need for the standing army. The technology is the same
> and the economic impact of a launch failure is far too high to cut
> corners here (NASA testified that the economic impact of Challenger
> was $13B in $Y2K, which, coincidentally, is equal to NASA's average
> annual budget in the shuttle era).
Nobody *at NASA* has been able to eliminate the need for the standing
army. And, indeed, considering that the Shuttle is closer to a research
and development project than an operational vehicle, it may be
impossible for NASA to function any other way. I respectfully disagree
with your assertion that it would be impossible to do SSTO without such
a standing army -- but this is something that can only be proved by
somebody doing it, which I alas am in no position to do. I'm rooting
for the little guys, though.
The magnitude of the economic impact of launch failure is a symptom of
the dysfunctional way of doing launches now; if, instead, the worst
result of a failed launch were that they'd have to try again tomorrow or
the next day, instead of having a destroyed vehicle and payload and a
major stand-down and investigation, then 13 gigadollars need not ride on
each individual success. How can that be made the worst result? Only
by having reliability on a par with airliners, which in turn can only be
assured if *each specific vehicle* can be repeatedly tested and trusted
to function even in the face of multiple hardware failures.
> I don't recall that a shuttle flight was actually launched with a
> large piece of GSE inadvertently left in the payload bay. Someone in
> the shuttle organization apparently makes sure this type of screwup
> doesn't happen. Probably someone in the standing army.
Maybe you need that one guy, without the rest of the army.
Edward Wright
>> On caveat here. It makes a huge difference once organization is
doing
>> the project. I remember a few years ago, an engineer was asking how
>> much it would cost to build the DC-Y. He replied something like,
"$500
>> million if it were a private company doing it, a billion if DARPA
or
>> SDIO does it under streamlined management, $5 billion if it's a
>> standard Air Force contract, and $20 billion if NASA does it.
> I hope that you are not suggesting that NASA is some kind of blundering
> organization of idiots and incompetents. Today, in the early 21st century,
> that kind of NASA-bashing is becoming tedious and worn out.
I wasn't. But since you mention it, NASA spent $1 billion trying to
achieve single-stage-to-Montana, and failed. NASA spent $150 million
trying to build a winged vehicle with performance equivalent to the
X-15, and failed. Those are not sinces of institutional competence.
> However, I also know that NASA-bashing continues to be a popular pasttime,
> especially among some of the advocates of various SSTO launch vehicle
> schemes. I came into contact with many of these folks during the DC-X/XA
> days, and, I regret to say, that I detected a definite odor of elitism in
> that group.
I take it you never actually met any of them, then?
> The attitude is that NASA incompetence had tied the shuttle up
> in a mountain of red tape with its tedious Flight Readiness Review (FRR)
> process and all the other paperwork that floats around that system. The
> argument is that an shuttle-size SSTO, operated by a small group of
> super-competent individuals, would not require all the operating expense
> associated with NASA shuttle red tape.
No, that was not, and is not, the argument. The argument is that
spacecraft should be maintained by high school graduates and flown by
history majors, as aircraft are. Super-competent individuals are
neither needed nor wanted. Besides, they're in short supply since
Krypton exploded. :-)
> The result would be shuttle-size SSTO launch vehicles with airline-type operational cost. This is grade-A BS.
> Any would-be SSTO replacement for the shuttle would have the same operating
> costs, simply because today's technology, that would be used by that SSTO,
> is the same as that used 30 years ago for the original shuttle.
Your conclusion is correct, but the premise you base it on is flawed.
The Shuttle is expensive because the flight rate is low, which is a
function of the market (or lack thereof). It could be powered by
antimatter or antigravity, and it would still be expensive. Developing
better (read "more expensive") technology will not a Shuttle
replacement cheaper.
>The red tape is there primarily to ensure misison success and
astronaut safety. Neglecting procedures and cutting corners
> caused the Challenger loss and, by NASA's own estimates, a $13B ($Y2K) cost impact (see chapters 45 and 55 of
> my book). No privately financed SSTO shuttle replacement could get flight
> insurance unless the pre-flighting of that vehicle were at least as thorough
> and detailed as NASA's shuttle flight recertification process.
Every airliner in the world has insurance, and none go through the
sort of preflight process the Shuttle does. The EZ-Rocket had no
trouble obtaining insurance.
> As far as the cost effectiveness of building DC-Y's in a private company, I
> have only a few words to say: "X-33" and "Skunk Works".
You don't think NASA was involved in X-33?
>> You might change your mind if you heard what Burt Rutan said about
>> X-38 at Oshkosh last year. "You'd have to be pretty sick to ride in
>> it." BTW, the numbers I've seen indicate that X-38 is badly over
>> budget.
>
> Burt is probably referring to the well-known history of lifting bodies with
> their high landing speeds and the various aerodynamic instability modes that
> can afflict these vehicles.
No, he was referring to X-38. Since his company built the first X-38
airframe, I presume he knows more about it than what he read in the
history books.
> It's very likely that some of the lifting body
> pilots thought the same about Rutan's Voyager aircraft. Beauty (and risk) is
> in the eye of the beholder.
But flying characteristics are in the hands of aerodynamics.
> I'm quite a bit more optimistic than Rutan since the X-38 is derived from
> the Martin X-24A lifting body of the late 1960s and early 1970s. The X-24A,
> in turn, was derived from the SV-5B/PRIME vehicle that made three very
> successful sub-orbital flights to Mach 23. The 3rd SV-5B flight vehicle
> demonstrated about 710 n. mi. of cross-range capability and its parachute
> was snagged by the C-130 recovery plane about 5 n. mi from the target.
You can catch geese in a net, too. That doesn't mean I'd want to ride
one.
rschmitt23
> In article <7NOc9.40558$Ic7.2...@news2.west.cox.net>, rschmitt23 wrote:
>
> > "Mark Bradford" <t...@surly.org> wrote in message
> > news:slrnan722...@surly.org...
>
>
> savings in costs and increased capability will arise from miraculous new
> technological advances. I'm saying that making different choices,
> *using the same level of technology* (but different specific
> technologies, such as avoiding staged combustion, sticking with kerosene
> over LH2, over-engineering the vehicle and not running it at the edge of
> the envelope, or other methods to simplify maintenance) would likely
> result in reduced operating costs and risks.
>
> A fresh-start SSTO would not be obligated to re-invent the Shuttle as it
> exists.
Thanks for your input. You're on the right track here, but the SSTO is not
the answer. There are other options that use the existing technology in a
truly cost effective and synergistic manner and which promote the ENTIRE
spectrum of manned spaceflight activities (both LEO and deep space
missions). The keys are to simplify, to employ reusable flight hardware in
the most effective manner (i.e. in the Crew Rotation Vehicle, not in the
booster), to use modularity effectively (not the way it's used in the ISS),
and to minimize the number of separate production lines needed to support
the space transportation infrastructure (see chapters 27 and 56 of my book).
Ray Schmitt
Author: "U.S. Manned Spaceflight in the 20th Century: The Successes. The
Failures. The Options."
http://www.amazon.com/exec/obidos/ASIN/0972101004/qid%3D1031063372/sr%3D11-1
/ref%3Dsr%5F11%5F1/002-2150999-9328856
Mark Bradford
> Thanks for your input. You're on the right track here, but the SSTO
> is not the answer. There are other options that use the existing
> technology in a truly cost effective and synergistic manner and which
> promote the ENTIRE spectrum of manned spaceflight activities (both LEO
> and deep space missions). The keys are to simplify, to employ reusable
> flight hardware in the most effective manner (i.e. in the Crew
> Rotation Vehicle, not in the booster), to use modularity effectively
> (not the way it's used in the ISS), and to minimize the number of
> separate production lines needed to support the space transportation
> infrastructure (see chapters 27 and 56 of my book).
Without having seen your book, I can certainly support the notions of
effective modularity and maximal commonality (minimal production lines);
those are sound principles, at least within a single supplier. (It
could be argued that for maximum efficiency, you *need* multiple
production lines -- from competing suppliers!)
I have to question your statement that reusable booster hardware is not
as effective as reusable vehicles, though. So long as you're throwing
your booster away every time, you're not launching a system that has
actually been tested, just one that's "just like" all the others that
have been tested. You won't achieve true airliner-like reliability
until your entire launch system, booster and vehicle alike (be it one
stage, two stages, whatever) is reusable and testable.
Edward Wright
> There are other options that use the existing technology in a
> truly cost effective and synergistic manner and which promote the ENTIRE
> spectrum of manned spaceflight activities (both LEO and deep space
> missions). The keys are to simplify, to employ reusable flight hardware in
> the most effective manner (i.e. in the Crew Rotation Vehicle, not in the
> booster),
Isn't that essentially what NASA did do? The reusable part of the
Shuttle is the orbiter ("crew rotation vehicle"). Okay, the SRBs are
refurbished, but NASA could eliminate the parachutes and let them sink
if they wanted to. As a thought experiment, suppose you did do that
and while you're at it, remove the SSMEs from the orbiter to the
expendable booster portion. Call it Shuttle II or, better yet, call it
"Buran." It would still be very expensive to operate. So expensive
that the government might decide to hangar it after just a couple test
flights.
> to use modularity effectively (not the way it's used in the ISS),
> and to minimize the number of separate production lines needed to support
> the space transportation infrastructure (see chapters 27 and 56 of my book).
Minimize the number of production lines? More than we've done
already?Aerospace consolidation hasn't reduced the cost of jet
fighters. What leads you to believe it will reduce the cost of space
transportation.
As Yogi Berra might say, competition is a good thing, especially when
you have multiple competitors.
Ian Woollard
> "Mark Bradford" <t...@surly.org> wrote in message
> news:slrnan722...@surly.org...
> > In article <sDAc9.39547$Ic7.2...@news2.west.cox.net>, rschmitt23 wrote:
> > I don't think anyone would suggest that; however, NASA *is* a ponderous
> > organization laden with managers and bureaucrats (in addition to large
> > numbers of professional and competent engineers and scientists).
> >
>
> Thanks for your input. From my experience with NASA over three decades, the
> NASA managers manage as well as or better than the prime contractor
> managers.
Yes, well...
> Savvy managers inside NASA and the
> prime contractor organizations know how to use the bureaucracy to get done
> what needs to be done.
And sometimes they even build rockets and stuff.
> Flash! Today's technology is the same as the 1970s variety used in the
> original shuttle. I know this for a fact. I worked for four years on
> shuttle TPS from 1968 through 1972 and then on X-33 TPS from 1995-96. The
> TPS technology is the same, the structures and propellant tank technologies
> are the same. The liquid rocket engine technology is the same. And the
> software development technology is the same. The only difference now is that
> the flight computer hardware of the next generation shuttle replacement will
> be greatly improved over the 1970s IBM 370 technology used in the original
> shuttle. But this represents a miniscule part of the cost. Flight software
> development and verification and validation (V&V) is still as tedious and
> expensive today as it was in the 1970s. Witness Boeing's struggle with the
> ISS software development and V&V effort in the late 1990s, continuing to the
> present.
> The development and operating costs and the operating risks associated with
> the next generation shuttle replacement will be the same as those of the
> present shuttle, BECAUSE THE TECHNOLOGY IS THE SAME.
Flash! Ruskies use much the same technologies that NASA uses!
But theyare more than an ORDER OF MAGNITUDE CHEAPER...
Flash! The Russians launch hardware for less than the US cost-
even when you take into account the lower wages...
Flash! The technology used in Ferrari and a BMW is the same! But one
is many times cheaper than the other!
> Write these words on a
> piece of paper, tape it to your bathroom mirror and repeat the words ten
> times each morning while you shave and/or take care of those annoying skin
> blemishes that lately have put a crimp in your social life.
NASA workers must do this every morning huh? Standard
operating procedure?
> Your point about manpower being the major shuttle operating cost is an old
> and well known fact. A.O Tischler, Head of the Chemical Propulsion Division
> of NASA's Office of Advanced Research and Technology, said the same thing in
> early 1969. In 1984 James Beggs, the then NASA Administrator, testified
> before a House subcommittee concerning the "standing army" that is necessary
> to operate the shuttle organization. Dan Goldin said essentially the same
> thing numerous times during the 1990s as he shuffled the deck and tried to
> find some way to reduce the headcount by off-loading shuttle flight
> re-certification work to the USA organization and to other contractors (see
> chapter 44 of my book).
Yes, well it's a bit late now. The time for minimising that
is on the drawing board when you are designing in/out SRBs and
specifying the ISP for the SSMEs, choosing hydrogen or not.
hint: SRBs aren't worth reusing. hint2: hydrogen for lift off
hasn't exactly proven to be stunningly cost effective.
> The point is that nobody has been able to change this during the last 30
> years. And despite what we at McDonnell Douglas said in the DC-X/XA/Y sales
> brochures of the 1990-96 period, it is unlikely that anything the SSTO
> proponents or the SLI guys and gals come up with will change the need for
> the standing army.
Oh right. And you know they were wrong because...? And the
army needed to build DC-X was incredibly large. Oh wait, no it
wasn't...
> The technology is the same and the economic impact of a
> launch failure is far too high to cut corners here (NASA testified that the
> economic impact of Challenger was $13B in $Y2K, which, coincidentally, is
> equal to NASA's average annual budget in the shuttle era).
There's a difference between cutting corners and cutting manpower.
It's easy to do both. But one does not imply the other. Indeed I
have seen cases where cutting manpower improves reliability;
people's ass are on the line- they cannot screw up. With multiple
levels of people checking, nobody double checks, and sometimes
they don't single check.
Don't forget that the Saturn V was cheaper than the Space Shuttle
per pound. Oh, but I forgot, it's not possible to do it any cheaper
than the Space Shuttle.
> Later
> Ray Schmitt
Scott Lowther
> Flash! Ruskies use much the same technologies that NASA uses!
> But theyare more than an ORDER OF MAGNITUDE CHEAPER...
It's amazing what you can develop with forced labor.
--
Scott Lowther, Engineer
rschmitt23
"Edward Wright" <edwrig...@hotmail.com> wrote in message
news:32b558f9.02090...@posting.google.com...
>
>
> Shuttle is the orbiter ("crew rotation vehicle"). Okay, the SRBs are
> refurbished, but NASA could eliminate the parachutes and let them sink
> if they wanted to. As a thought experiment, suppose you did do that
> and while you're at it, remove the SSMEs from the orbiter to the
> expendable booster portion. Call it Shuttle II or, better yet, call it
> "Buran." It would still be very expensive to operate. So expensive
> that the government might decide to hangar it after just a couple test
> flights.
>
Thanks for the input. You're absolutely correct about the SRBs (see chapter
44 of my book).
Regarding the SSMEs, through the first 100 shutttle flights, NASA spent
about $3.7B operating the SSMEs, about $1.3B upgrading them (primarily the
Pratt & Whitney turbopumps) for a total of $5B (all costs in $Y2K). If the
SSME were manufactured as an expendable engine, its unit cost would be about
$30M, instead of nearly $50M per copy for the reusable version that, so far,
has been qualified for 20 reuses. It would have cost NASA about $9B for 300
expendable SSMEs on the first 100 flights. So the savings resulting from
SSME reusability is about $4B during the first two decades of shuttle
operation. During that time, the total shuttle program cost amounted to
about $116B, which means that the SSME reusability savings is about 3% of
total program cost. This is roughly what one would expect from the
econometric analysis of the original shuttle that Mathematica, Inc.
generated in 1970-71 under NASA contract (see chapter 31 of my book).
And yes, NASA is using the shuttle as an ISS crew rotation vehicle (what
other choice is there now other than Soyuz). Apparently I've generated
confusion here by not being more precise. By "CRV" I was referring to a
vehicle that functions both as a crew rotation vehicle and as a crew rescue
vehicle. I probably should have used the old term ACRV (Assured Crew Return
Vehicle) when I'm talking about CRVs like the Soyuz which can perform both
functions and can remained docked at the ISS for several months.
The present 250,000-pound shuttle orbiter, with its huge payload bay and
massive payload capacity, is far more than the dual-purpose CRV to which I
am referring. That CRV is, by definition, a personnel transport system for
at least 6 persons with wet weight in the 40,000-50,000-pound range and with
a relatively small cargo capacity, 5000 pounds or less, up and down. And,
in fact, the shuttle orbiter is unable to function as a dual-purpose CRV
since it cannot, for operational and economic reasons, remained docked to
the ISS for 3-4 months like the Soyuz CRVs or like the old Apollo CSM in the
case of Skylab in the early 1970s.
My point is that the reusable part of the basic Earth-to-orbit (ETO) segment
of the national space transportation system that supports our manned
spaceflight effort should be limited to the relatively small, dual-purpose
CRV that I mentioned previously. All of the other parts of the ETO segment
should be expendable flight hardware. This is the only way to minimize
development and operating cost simultaneouly (see chapter 56 of my book).
From what I can discern of the current SLI activity, some of those folks are
coming to a similar conclusion. And I think that the Delta IV folks at
Boeing, the Atlas V troops at Lockmart, the guys and gals at Ariane V, and,
last but not least, the Proton folks at Energia and Khrunichev are tuning in
to this way of handling the ETO segment of manned spaceflight. All of these
organizations have dual-use CRV designs on the drawing boards, designs sized
for their individual ELVs. However, the primary problem here is that all
four of these ELVs are marginal for cost effective manned ETO service
because their payload capability is only 30,000 to 40,000 pounds to the ISS
orbit. What is needed is a cost-effective ELV with about 60,000 to 70,000
pound capability to the ISS (see chapters 27 and 56 of my book).
> > to use modularity effectively (not the way it's used in the ISS),
> > and to minimize the number of separate production lines needed to
support
> > the space transportation infrastructure (see chapters 27 and 56 of my
book).
>
> Minimize the number of production lines? More than we've done
> already?Aerospace consolidation hasn't reduced the cost of jet
> fighters. What leads you to believe it will reduce the cost of space
> transportation.
This is a lengthy subject having to do with launch vehicle versatility,
design flexibility, and budgetary survivability (see the reference cited
above for details).
Ray Schmitt
Author: "U.S. Manned Spaceflight in the 20th Century: The Successes. The
Failures. The Options."
http://www.amazon.com/exec/obidos/ASIN/0972101004/qid%3D1031111118/sr%3D11-1
/ref%3Dsr%5F11%5F1/002-2150999-9328856
Edward Wright
>> Flash! Ruskies use much the same technologies that NASA uses!
>> But theyare more than an ORDER OF MAGNITUDE CHEAPER...
>
> It's amazing what you can develop with forced labor.
Russian launch vehicles are not built by forced labor. In fact, these
days, the people who build them sometimes drive cabs at night so they
can continue to build rockets during the day.
Perhaps you were thinking of the V-2?
Scott Lowther
>
> Scott Lowther <lex...@ix.netcom.com> wrote in message news:<3D756A...@ix.netcom.com>...
>
> >> Flash! Ruskies use much the same technologies that NASA uses!
> >> But theyare more than an ORDER OF MAGNITUDE CHEAPER...
> >
> > It's amazing what you can develop with forced labor.
>
> Russian launch vehicles are not built by forced labor.
Pop quiz, hotshot: Russian launch vehicles and their infrastructure were
developed by:
A) The European Union
B) The Union of Concerned Scientists
C) The Soviet Union
The Soviet Union was:
A) A nice place
B) A workers paradise
C) A totalitarian state built on forced labor
> In fact, these
> days, the people who build them sometimes drive cabs at night so they
> can continue to build rockets during the day.
That's nice. It's amazing what you can do with infrastructure that was
developed with forced labor.
> Perhaps you were thinking of the V-2?
Perhaps you need to actually read before you respond?
--
Scott Lowther, Engineer
jsa...@ecn.ab.ca
: The magnitude of the economic impact of launch failure is a symptom of
: the dysfunctional way of doing launches now; if, instead, the worst
: result of a failed launch were that they'd have to try again tomorrow or
: the next day, instead of having a destroyed vehicle and payload and a
: major stand-down and investigation, then 13 gigadollars need not ride on
: each individual success. How can that be made the worst result? Only
: by having reliability on a par with airliners, which in turn can only be
: assured if *each specific vehicle* can be repeatedly tested and trusted
: to function even in the face of multiple hardware failures.
You would also have to do only unmanned launches.
Of course, even if the loss of the payload, or even loss of human life,
were a result of a failed launch, if one had a launch system acknowledged
to be reliable from much past experience, having to try again the next day
might well be the maximum _operational_ impact of a failure in addition to
the loss of the individual payload.
But loss of a human life is still worse than having to repeat a launch.
Consider this a quibble about English usage.
John Savard
Mike Atkinson
rschmitt23 wrote:
> Regarding the SSMEs, through the first 100 shutttle flights, NASA spent
> about $3.7B operating the SSMEs, about $1.3B upgrading them (primarily the
> Pratt & Whitney turbopumps) for a total of $5B (all costs in $Y2K). If the
> SSME were manufactured as an expendable engine, its unit cost would be about
> $30M, instead of nearly $50M per copy for the reusable version that, so far,
> has been qualified for 20 reuses. It would have cost NASA about $9B for 300
> expendable SSMEs on the first 100 flights. So the savings resulting from
> SSME reusability is about $4B during the first two decades of shuttle
> operation. During that time, the total shuttle program cost amounted to
> about $116B, which means that the SSME reusability savings is about 3% of
> total program cost. This is roughly what one would expect from the
> econometric analysis of the original shuttle that Mathematica, Inc.
> generated in 1970-71 under NASA contract (see chapter 31 of my book).
Does that $3.7B operating the SSMEs include the cost of removing them
from the shuttle and replacing them, or just their inspection/repair/
refurbishment? Does this figure include consequent costs (e.g. potential
fault in SSME leading to destacking, SSME removal, inspection, swapping,
replacement, stacking, etc.)?
Using the standard aerospace scaling factor of a 0.85 reduction in unit
cost for a doubling in production would suggest that SSMEs with no
design or qualification changes but used expendably would cost under
$25M each. They could be designed for 20 reuses (minus some
maintainability features) but only qualified for one flight giving
further savings, probably to the $20M unit cost level. So the costs of
expendable SSMEs would probably still have been more (but only 20% or
so, or 1% of total program cost).
If that were the end of potential cost savings then I would agree with
you. However:
1. not returning the SSMEs would reduce the landing mass of the shuttle,
this leads to:
a. smaller, lighter undercarrage.
b. potential for improving the aerodynamics due to CoG moved forward.
c. lower landing angle.
d. better cross-range.
e. lower reentry heating per unit area (the shuttle volume would
remain the same as it is mainly defined by payload and crew
volumes). This leads to savings in mass/cost of thermal
protection.
2. there would need to be no fuel cross-link between the external tank
and shuttle, removing potential failure modes and I suspect reducing
mass as well [and reducing stacking time?].
3. by making the external tank and SRB stack independent of the shuttle
for propulsion, it would be trivial to create a shuttle-C. This would
have reduced costs for the ISS by several *tens of billions*, by
enabling it to be launched already constructed in one flight.
4. shuttle turn arround times would be reduced as there would be no need
to remove and replace the SSMEs. SSMEs could be attached to the
external tank in the factory, so stacking time in the VAB would not
change much.
Taken together these advantages seem to lead to either a smaller vehicle
and hence lower cost (for the same payload) or more payload and hence
lower cost per pound.
Ian Woollard
>
> > Flash! Ruskies use much the same technologies that NASA uses!
> > But theyare more than an ORDER OF MAGNITUDE CHEAPER...
>
> It's amazing what you can develop with forced labor.
Yes.
But we are talking about the Russians, not the Nazis. For some
reason you seem to assume that it's related to politics. I don't
think it is. In fact the converse is true, the expense of NASA
hardware is related to politics. But I think that the politics
only make the issues worse, it's not the source of the problem.
It's about things like production quantities, manufacture
techniques, working at reducing the number of people involved
rather than keeping them at some magic threshold number; or
working at increasing the volume, whilst keeping the number of
people the same.
The Russians have used horizontal assembly for example- that has
been shown to be cheaper- some american launchers are doing it
that way now. The Russians often use dense propellents those
usually are cheaper. (So did Saturn V first stage of course,
and that was very much cheaper than the Shuttle which uses LH).
It's not that the Russians are a shining example of perfection-
(I don't want to live there!), it's just that they do things much
less expensively; NASA needs to learn. NASA could do
twice as much if they could do it for half the mission costs.
Jon Berndt
> 2. there would need to be no fuel cross-link between the external tank
> and shuttle, removing potential failure modes and I suspect reducing
> mass as well [and reducing stacking time?].
It sounds like you are putting expendable engines under the ET - removing
them from the shuttle entirely? If true, I am not sure about the feasibility
of mounting the shuttle on the side. It seems like aero load concerns (and
other factors) would preclude this approach, but at the moment I can't
provide any backing to this.
> 3. by making the external tank and SRB stack independent of the shuttle
> for propulsion, it would be trivial to create a shuttle-C. This would
> have reduced costs for the ISS by several *tens of billions*, by
> enabling it to be launched already constructed in one flight.
!? In one flight? Surely you jest.
Jon
Paul Blay
> Scott Lowther <lex...@ix.netcom.com> wrote in message news:<3D756A...@ix.netcom.com>...
> > Ian Woollard wrote:
> >
> > > Flash! Ruskies use much the same technologies that NASA uses!
> > > But theyare more than an ORDER OF MAGNITUDE CHEAPER...
> >
> > It's amazing what you can develop with forced labor.
>
> (I don't want to live there!), it's just that they do things much
Partially because the labour force is paid 'in kind', if at all.
After the story of the Russian worker who went on hunger strike to
protest the lack of wages, and was finally paid off in meat grinders
I'm looking forward to the first worker at NPO Energia to be paid
off with 1/20,000th of a Soyuz TM.
Scott Lowther
>
> Scott Lowther <lex...@ix.netcom.com> wrote in message news:<3D756A...@ix.netcom.com>...
> > Ian Woollard wrote:
> >
> > > Flash! Ruskies use much the same technologies that NASA uses!
> > > But theyare more than an ORDER OF MAGNITUDE CHEAPER...
> >
> > It's amazing what you can develop with forced labor.
>
> Yes.
>
> But we are talking about the Russians, not the Nazis.
No, we're talking about the Soviets, who were close enough to the Nazis
as to make no difference in this regard. The current modern Russian
space program... spacecraft, launchers and infrastructure... were made
largely be people who didn't have a lot of choice in the matter. When
the Soviets went away, their space program and it's infrastructure did
not, allowing the Russians to start with an already built and paid for
system.
--
Scott Lowther, Engineer
Rick C
> > 3. by making the external tank and SRB stack independent of the shuttle
> > for propulsion, it would be trivial to create a shuttle-C. This
would
> > have reduced costs for the ISS by several *tens of billions*, by
> > enabling it to be launched already constructed in one flight.
> !? In one flight? Surely you jest.
Obviously it wouldn't look like the current design. You'd have one huge
module.
Rand Simberg
Berndt" <a@b.c> made the phosphor on my monitor glow in such a way as
to indicate that:
>It sounds like you are putting expendable engines under the ET - removing
>them from the shuttle entirely? If true, I am not sure about the feasibility
>of mounting the shuttle on the side. It seems like aero load concerns (and
>other factors) would preclude this approach, but at the moment I can't
>provide any backing to this.
That was the basic configuration of Buran. It could be done, but it
would be a different vehicle than the Shuttle.
>> 3. by making the external tank and SRB stack independent of the shuttle
>> for propulsion, it would be trivial to create a shuttle-C. This would
>> have reduced costs for the ISS by several *tens of billions*, by
>> enabling it to be launched already constructed in one flight.
>
>!? In one flight? Surely you jest.
Not this particular station, but one at least as useful. Additional
flights might be required to enhance it, but a basic station could
have been launched in a single flight of a Shuttle-derived vehicle
(though not Shuttle-C).
rschmitt23
news:3db71592....@nntp.ix.netcom.com...
>It sounds like you are putting expendable engines under the ET - removing
> >them from the shuttle entirely? If true, I am not sure about the
feasibility
> >of mounting the shuttle on the side. It seems like aero load concerns
(and
> >other factors) would preclude this approach, but at the moment I can't
> >provide any backing to this.
>
> That was the basic configuration of Buran. It could be done, but it
> would be a different vehicle than the Shuttle.
Rand:
In 1979 NASA and the Air Force studied "enhancements" to the shuttle that
would add a package of liquid engines or SRMs to the bottom of the ET. The
problem facing NASA was the inability of the shuttle to satisfy the Air
Force's demand for 32,000 pounds of payload to a 100 n. mi. circular polar
orbit, launched from Vandenberg. Apparently, the structure of the ET can be
modified relatively easily to handle the trust loads from this arrangement.
The liquid engine package consisted of two Aerojet LR-87-AJ-11 engines
(Titan II engines, about 475,000 pounds average thrust each) and four
NTO/MMH tanks. The engines were started 5 seconds after launch and burned
for about 200 seconds. Adds about 12,000 pounds of payload capability,
according to NASA, Martin Marietta and Aerojet estimates.
The SRB package added 8,000-10,000 pounds of payload lift.
I don't know if the standard ET configuration could handle the thrust from
three SSMEs (1.5 million pounds) pushing on the bottom of the main hydrogen
tank. The structure there probably would have to be beefed up (see chapter
35 of my book).
Later.
Ray Schmitt
Author: "U.S. Manned Spaceflight in the 20th Century: The Successes. The
Failures. The Options."
http://www.amazon.com/exec/obidos/ASIN/0972101004/qid%3D1031152857/sr%3D11-1
/ref%3Dsr%5F11%5F1/002-2150999-9328856
"Rand Simberg" <simberg.i...@trash.org> wrote in message
news:3db71592....@nntp.ix.netcom.com...
Ian Woollard
> No, we're talking about the Soviets, who were close enough to the Nazis
> as to make no difference in this regard.
No.
How many thousands died under the Nazis? They were working
under concentration camp conditions on the V2.
The Russian conditions were not in any way comparable. They were paid,
fed, housed, educated. Under the NAZIs they were living in true slave
labour camps. To equate the two... that is both inaccurate and
insulting to both those peoples.
> The current modern Russian
> space program... spacecraft, launchers and infrastructure... were made
> largely be people who didn't have a lot of choice in the matter.
Saturn V. Did the Germans really have much choice?
Mike Atkinson
Jon Berndt wrote:
> "Mike Atkinson" <mi...@cre.canon.co.uk> wrote in message
>
>
>>2. there would need to be no fuel cross-link between the external tank
>> and shuttle, removing potential failure modes and I suspect reducing
>> mass as well [and reducing stacking time?].
>
>
> It sounds like you are putting expendable engines under the ET - removing
> them from the shuttle entirely? If true, I am not sure about the feasibility
> of mounting the shuttle on the side. It seems like aero load concerns (and
> other factors) would preclude this approach, but at the moment I can't
> provide any backing to this.
Yes, putting expendable SSME under the external tank makes sense, after
all the main reason they are on the orbiter is that it is recovered
while the external tank isn't. Proof of concept is Buran, which had a
similar configuration.
>
>
>>3. by making the external tank and SRB stack independent of the shuttle
>> for propulsion, it would be trivial to create a shuttle-C. This would
>> have reduced costs for the ISS by several *tens of billions*, by
>> enabling it to be launched already constructed in one flight.
>
>
> !? In one flight? Surely you jest.
>
No, a large space station equivalent to about where we are now in the
ISS build out could be launched in one go. I'm not saying its easy, but
then neither is the ISS build process. Integration on the ground and
better mass efficiency by having a larger pressure shell should make it
much cheaper to design and build as well as launch.
Mike Atkinson
forward now. Instead I am looking at what the effects of a decission in
the early 1970's to use expendable SSMEs would have been, while keeping
most of the other parameters of the shuttle design the same. I think
that with hindsight, expendable SSMEs placed on the external tank would
have lead to a better vehicle (even if the 50/year target flight rate
where achieved).
Edward Wright
> Regarding the SSMEs, through the first 100 shutttle flights, NASA spent
> about $3.7B operating the SSMEs, about $1.3B upgrading them (primarily the
> Pratt & Whitney turbopumps) for a total of $5B (all costs in $Y2K).
All this shows is that the SSME has poor economics. Not surprising,
since it was optimized for performance rather than low operating
costs.
> If the SSME were manufactured as an expendable engine, its unit cost would be about
> $30M, instead of nearly $50M per copy for the reusable version
An expendable engine? What do you mean by that? Del Tischler said, "I
don't know how to build an expendable rocket engine." An engine has to
be reusable so engineers can afford to fire it during the test
program. I think astronauts would have some concerns about riding on
an expendable engine that had never been fired.
Buran discarded its main engines. (Although the engines themselves
were reusable, the booster was not.) That didn't make Buran cheap. In
fact, it died of sticker shock when the Russians found out what it
cost.
> And yes, NASA is using the shuttle as an ISS crew rotation vehicle (what
> other choice is there now other than Soyuz). Apparently I've generated
> confusion here by not being more precise. By "CRV" I was referring to a
> vehicle that functions both as a crew rotation vehicle and as a crew rescue
> vehicle.
NASA has considered using the Shuttle as a crew rescue vehicle, too.
It might not be a bad idea, all things considered. However, it would
not make the Shuttle any cheaper.
> I probably should have used the old term ACRV (Assured Crew Return
> Vehicle) when I'm talking about CRVs like the Soyuz which can perform both
> functions and can remained docked at the ISS for several months.
Apollo did that 30 years ago, but Apollo was not supercheap. There's
no reason to believe a new CRV will be, either. In fact, when you look
at the development cost and divide it by the flight rate, you can be
sure it won't be.
> The present 250,000-pound shuttle orbiter, with its huge payload bay and
> massive payload capacity, is far more than the dual-purpose CRV to which I
> am referring.
Irrelevant. The development costs for that 250,000-pound orbiter have
already been paid for, so when you compare the Shuttle and its
replacement options, they don't appear in the spreadsheet. A new CRV
would have to be paid for with new money.
You can think of the Space Shuttle as being like the NASA Guppies or
the DC-3s that still fly in places like Alaska. They may be old, the
technology may be dated, and they require a lot of maintenance
compared to more modern planes. Yet, no one replaces them, because
they still do the job and the investment to replace them is much too
high for the amount of work they do. It's the same with any Shuttle
replacement, including the CRV (X-38, RStar, or whatever NASA's
calling it this week). Think of Shuttle as the Space Guppy.
> That CRV is, by definition, a personnel transport system for
> at least 6 persons with wet weight in the 40,000-50,000-pound range and with
> a relatively small cargo capacity, 5000 pounds or less, up and down.
Well, that's one possible implementation of a CRV. That's one of
NASA's biggest problems. They like to specify solutions rather than
simply stating their actual requirements and allowing the market to
determine a solution. Until they start to do that, NASA's costs will
never come down appreciably.
> And, in fact, the shuttle orbiter is unable to function as a dual-purpose CRV
> since it cannot, for operational and economic reasons, remained docked to
> the ISS for 3-4 months like the Soyuz CRVs or like the old Apollo CSM in the
> case of Skylab in the early 1970s.
I think you've missed some recent studies. There's an astronaut (the
name eludes me) who's published a way of modifying the Shuttle to do
just that.
> My point is that the reusable part of the basic Earth-to-orbit (ETO) segment
> of the national space transportation system that supports our manned
> spaceflight effort should be limited to the relatively small, dual-purpose
> CRV that I mentioned previously. All of the other parts of the ETO segment
> should be expendable flight hardware. This is the only way to minimize
> development and operating cost simultaneouly (see chapter 56 of my book).
That begs the question. If that's try, why have previous ELVs been so
expensive to develop and operate? What would you do differently to
reduce costs, and how are you going to reduce costs enough to get a
decent return on the vehicle that's only going to fly four times a
year? (Don't say you don't need to worry about return because the
government is going to provide the money. You still need to consider
the cost of money if you want to do a proper accounting.)
> From what I can discern of the current SLI activity, some of those folks are
> coming to a similar conclusion. And I think that the Delta IV folks at
> Boeing, the Atlas V troops at Lockmart, the guys and gals at Ariane V, and,
> last but not least, the Proton folks at Energia and Khrunichev are tuning in
> to this way of handling the ETO segment of manned spaceflight.
It's hardly surprising that companies come to the conclusion that
their products are better than anybody else's. I seriously doubt NASA
will consider Ariane or Proton for SLI, however.
> All of these organizations have dual-use CRV designs on the drawing boards,
> designs sized for their individual ELVs.
Well, Proton has some serious competition, since there's already a
Russian crew return vehicle called Soyuz. There may be some ideas on
the drawing board, but I doubt they'll go farther than that. No one in
Russia has the money for them right now, NASA doesn't want to fund
them, and if NASA does decide to go for a Russian option, they'll
almost certain choose Soyuz. It's cheaper, flight-ready, and while R&D
helps to create jobs, NASA doesn't earn any brownie points for
creating jobs in a foreign country.
> However, the primary problem here is that all
> four of these ELVs are marginal for cost effective manned ETO service
> because their payload capability is only 30,000 to 40,000 pounds to the ISS
> orbit.
Um, so? That's more than the gross weight of a DC-3, and that was the
primary American airlifter during the largest war of the 20th Century.
> What is needed is a cost-effective ELV with about 60,000 to 70,000
> pound capability to the ISS (see chapters 27 and 56 of my book).
Why? Once the last ISS module is in orbit, you don't need 60,000-pound
packages to deliver beans and bacon.
>> Minimize the number of production lines? More than we've done
>> already? Aerospace consolidation hasn't reduced the cost of jet
>> fighters. What leads you to believe it will reduce the cost of
space
>> transportation?
>
> This is a lengthy subject having to do with launch vehicle versatility,
> design flexibility, and budgetary survivability (see the reference cited
> above for details).
That doesn't answer the question. Can you give me examples to show
that defense consilidation has actually saved money?
Edward Wright
> Pop quiz, hotshot: Russian launch vehicles and their infrastructure were
> developed by:
> A) The European Union
> B) The Union of Concerned Scientists
> C) The Soviet Union
Scott, the Cold War is over. Put down your gun and come out of your
cave. Your family wants you to come home. :-)
Kim Keller
"Edward Wright" <edwrig...@hotmail.com> wrote in message
news:32b558f9.02090...@posting.google.com...
> days, the people who build them sometimes drive cabs at night so they
> can continue to build rockets during the day.
They drive cabs at night because their day job (building rockets) doesn't
pay enough for them to survive on.
rschmitt23
"Edward Wright" <edwrig...@hotmail.com> wrote in message
news:32b558f9.02090...@posting.google.com...
>
> An expendable engine? What do you mean by that? Del Tischler said, "I
> don't know how to build an expendable rocket engine." An engine has to
> be reusable so engineers can afford to fire it during the test
> program. I think astronauts would have some concerns about riding on
> an expendable engine that had never been fired.
>
> Buran discarded its main engines. (Although the engines themselves
> were reusable, the booster was not.) That didn't make Buran cheap. In
> fact, it died of sticker shock when the Russians found out what it
> cost.
>
All kidding aside. It's well known that the F-1 and J-2 engines used in the
Saturn V ELV were considered by NASA and the rest of the aerospace community
to be "expendable" engines, i.e. to be used for one flight only. And because
they were expendable, they were conservatively designed to be relatively
inexpensive to manufacture. The average manufacturing cost was about $10M
for the F-1 and $7.5M for the J-2 (in $Y2K). The chamber pressure was
relatively low (about 1000 psi for the F-1 and 763 psi for the J-2) as were
the turbopump speeds (5500 rpm for the F-1, 8,000 rpm for the J-2 LOX pump
and 26,000 rpm for the J-2 LH2 pump). Of course these engines had to be
capable of multiple firings in order to get through the ground test
certification wicket. In fact, these certification tests showed that the
F-1 and J-2 production engines were about as reusable as the SSME is today
(20 missions) (see chapter 12 of my book).
You may remember the Mercury/Redstone, Mercury/Atlas and Gemini/Titan (not
very many people do). The Mercury and Gemini astronauts did ride ELVs with
production engines that had not been fully test fired before, except
possibly for short 5 second burps on the pad. That's why they call it "The
Right Stuff." If and when Lance Bass gets his economic act together and
rides the Soyuz to the ISS, he will be riding an ELV with production engines
that have not been fired before.
The Apollo/Saturn managers were more conservative and test fired virtually
all of the ELV stages on the ground with a full load of propellant as part
of acceptance testing. NASA does essentially the same for the shuttle SSME
production units, which are extensively test fired on the ground. This was
the standard procedure before the Challenger disaster and remains so today.
According to Rocketdyne, by Dec 2000 the SSME program had accumulated about
800,000 seconds of operation (ground testing and flight operation). For
every second of SSME flight operation, the NASA has invested about 15
seconds on the SSME test stands.
>
> NASA has considered using the Shuttle as a crew rescue vehicle, too.
> It might not be a bad idea, all things considered. However, it would
> not make the Shuttle any cheaper.
>
The operative word here is "assured" as in Assured Crew Rescue Vehicle
(ACRV). The shuttle pre-flight processing time averages about 115 days, far
to long to consider using it as a reliable crew rescue vehicle.
>
> Apollo did that 30 years ago, but Apollo was not supercheap. There's
> no reason to believe a new CRV will be, either. In fact, when you look
> at the development cost and divide it by the flight rate, you can be
> sure it won't be.
>
> > The present 250,000-pound shuttle orbiter, with its huge payload bay and
> > massive payload capacity, is far more than the dual-purpose CRV to which
I
> > am referring.
>
> Irrelevant. The development costs for that 250,000-pound orbiter have
> already been paid for, so when you compare the Shuttle and its
> replacement options, they don't appear in the spreadsheet. A new CRV
> would have to be paid for with new money.
According to the X-38/CRV folks, they can develop a full-size version
carrying 6 persons and some small amount of cargo for about $500M and
produce a fleet of 3 or 4 production vehicles for under $1.5B in today's
dollars. A few numbers to put that into perspective (all in $Y2K, see my
book for details):
F-1 engine development: $769M
J-2 engine development: $389M
S-IC development (1st stage of Saturn V): $1.36B
S-II development (2nd stage of Saturn V): $1.0B
S-IVB development (3rd stage of Saturn V): $800M
CSM development: $5.3B
LM development: $2.9B
Shuttle orbiter development: $14B
SSME development: $3B
Shuttle SRB development: $1.3B
Shuttle ET development: $1.3B
Assuming that we can believe John Muratore's people who made the X-38/CRV
cost estimates, it appears that their little X-38/CRV vehicle is a bargain
compared to the $14B that NASA paid to develop the orbiter and the ~ $20B
spent to develop the original shuttle.
>
> > That CRV is, by definition, a personnel transport system for
> > at least 6 persons with wet weight in the 40,000-50,000-pound range and
with
> > a relatively small cargo capacity, 5000 pounds or less, up and down.
>
> Well, that's one possible implementation of a CRV. That's one of
> NASA's biggest problems. They like to specify solutions rather than
> simply stating their actual requirements and allowing the market to
> determine a solution. Until they start to do that, NASA's costs will
> never come down appreciably.
>
Re: costs. See above for the numbers.
> > And, in fact, the shuttle orbiter is unable to function as a
dual-purpose CRV
> > since it cannot, for operational and economic reasons, remained docked
to
> > the ISS for 3-4 months like the Soyuz CRVs or like the old Apollo CSM in
the
> > case of Skylab in the early 1970s.
>
> I think you've missed some recent studies. There's an astronaut (the
> name eludes me) who's published a way of modifying the Shuttle to do
> just that.
Maybe, maybe not. NASA has had a long-cherished dream to use extended
mission kits in the payload bay to support 30-day shuttle missions. No
reason why 60 or 90 days can't be done. Rockwell was able to increase the
endurance of the CSM to 90 days for use with Skylab, so I don't doubt that
NASA could do the same for the orbiter, assuming that it makes economic
sense and that NASA's non-ISS flight plans for the shuttle can be handled
with a 3-orbiter fleet.
>
> > My point is that the reusable part of the basic Earth-to-orbit (ETO)
segment
> > of the national space transportation system that supports our manned
> > spaceflight effort should be limited to the relatively small,
dual-purpose
> > CRV that I mentioned previously. All of the other parts of the ETO
segment
> > should be expendable flight hardware. This is the only way to minimize
> > development and operating cost simultaneouly (see chapter 56 of my
book).
>
> That begs the question. If that's try, why have previous ELVs been so
> expensive to develop and operate? What would you do differently to
> reduce costs, and how are you going to reduce costs enough to get a
> decent return on the vehicle that's only going to fly four times a
> year? (Don't say you don't need to worry about return because the
> government is going to provide the money. You still need to consider
> the cost of money if you want to do a proper accounting.)
Re: cost. See the numbers cited above.
>
> > From what I can discern of the current SLI activity, some of those folks
are
> > coming to a similar conclusion. And I think that the Delta IV folks at
> > Boeing, the Atlas V troops at Lockmart, the guys and gals at Ariane V,
and,
> > last but not least, the Proton folks at Energia and Khrunichev are
tuning in
> > to this way of handling the ETO segment of manned spaceflight.
>
> It's hardly surprising that companies come to the conclusion that
> their products are better than anybody else's. I seriously doubt NASA
> will consider Ariane or Proton for SLI, however.
Didn't mean to imply that NASA would do that. But there's no doubt that,
with the Hermes experience under their belt, the Ariane folks still have a
gleam in their eye to do manned Ariane V launches.
>
> > All of these organizations have dual-use CRV designs on the drawing
boards,
> > designs sized for their individual ELVs.
>
> Well, Proton has some serious competition, since there's already a
> Russian crew return vehicle called Soyuz. There may be some ideas on
> the drawing board, but I doubt they'll go farther than that. No one in
> Russia has the money for them right now, NASA doesn't want to fund
> them, and if NASA does decide to go for a Russian option, they'll
> almost certain choose Soyuz. It's cheaper, flight-ready, and while R&D
> helps to create jobs, NASA doesn't earn any brownie points for
> creating jobs in a foreign country.
>
> > However, the primary problem here is that all
> > four of these ELVs are marginal for cost effective manned ETO service
> > because their payload capability is only 30,000 to 40,000 pounds to the
ISS
> > orbit.
>
> Um, so? That's more than the gross weight of a DC-3, and that was the
> primary American airlifter during the largest war of the 20th Century.
>
> > What is needed is a cost-effective ELV with about 60,000 to 70,000
> > pound capability to the ISS (see chapters 27 and 56 of my book).
>
> Why? Once the last ISS module is in orbit, you don't need 60,000-pound
> packages to deliver beans and bacon.
ISS is not the Final Goal of human spaceflight. You need to broaden your
perspective, to extend your time horizon, and to think more ambitiously.
>
> >> Minimize the number of production lines? More than we've done
> >> already? Aerospace consolidation hasn't reduced the cost of jet
> >> fighters. What leads you to believe it will reduce the cost of
> space
> >> transportation?
> >
> > This is a lengthy subject having to do with launch vehicle versatility,
> > design flexibility, and budgetary survivability (see the reference cited
> > above for details).
>
> That doesn't answer the question. Can you give me examples to show
> that defense consilidation has actually saved money?
Not talking about defense consolidation. I'm referring to synergism,
modularity and multi-use flight hardware to support a concept for a space
transportation infrastructure, the idea for which dates back to the start of
the manned spaceflight era and is associated with visionaries like Wernher
von Braun and George Mueller (see chapters 27 and 56 in my book) .
Later
Ray Schmitt
Author: "U.S. Manned Spaceflight in the 20th Century: The Successes. The
Failures. The Options."
http://www.amazon.com/exec/obidos/ASIN/0972101004/qid%3D1031192226/sr%3D11-1
/ref%3Dsr%5F11%5F1/002-2150999-9328856
Scott Lowther
>
> Scott Lowther <lex...@ix.netcom.com> wrote in message news:<3D760A...@ix.netcom.com>...
> > No, we're talking about the Soviets, who were close enough to the Nazis
> > as to make no difference in this regard.
>
> No.
>
> How many thousands died under the Nazis? They were working
> under concentration camp conditions on the V2.
>
> The Russian conditions were not in any way comparable. They were paid,
> fed, housed, educated.
And millions were marched off into the hinterlands and never heard from
again. It was, what, abotu 3,000,000 German POWs that simply
disappeared? How many millions of Georgians and Ukranians did Stalin do
away with? Kruschev was better, but still a red commie dictator. Those
who were needed for the rocket programs were not exactly allowed to
choose another path.
> > The current modern Russian
> > space program... spacecraft, launchers and infrastructure... were made
> > largely be people who didn't have a lot of choice in the matter.
>
> Saturn V.
> Did the Germans really have much choice?
The Germans in Huntsville? Damned straight they did. They chose to
follow their dreams and get paid for it. They all could ahve easily
walked away, after 1950 or so.
--
Scott Lowther, Engineer
Scott Lowther
Sigh. Another classic Ed Wright "Avoid the point at all costs" non
sequitur.
Again: WHO DEVELOPED THE RUSSIAN SPACE INFRASTRUCTURE??????
--
Scott Lowther, Engineer
Pat Flannery
Edward Wright wrote:
On the other hand...there is this charming photo from the days when the
R-7 was first under construction...here, the base of the core stage
undergoes structural testing as two icons look on:
http://www.tsniimash.ru/Vved/Images/05bs.jpg
The individual whose painting is on the right was not noted for a
liberal approach to workers (or anyone else, for that matter.)
Pat
>
George William Herbert
>> [...]
>On the other hand...there is this charming photo from the days when the
>R-7 was first under construction...here, the base of the core stage
That's a R-7 core??
-george william herbert
gher...@retro.com
Pat Flannery
George William Herbert wrote:
>
>That's a R-7 core??
>
Yes indeedy- you hardly ever see them with the boosters off; the core
stage is very long, and quite slender over the bottom half of it's
length- the bulges toward the right hand side of the picture are the
housings for the four swiveling vernier motors of the central RD108 core
motor- the upper one is in place and swiveled to one side....the
indented band around the stage in about the middle of the picture is
where the lower struts attach to the four strap-on boosters.
There is a nice bottom shot showing the geometry of how everything
attaches together here:
http://www.astronautix.com/lvs/r7a8k74.htm
Pat
Michael Walsh
rschmitt23 wrote:
I believe you are missing a point. The F-1 and J-2 engines were not designed to
be inexpensive to manufacture. They were representative of the highest
technology
available at the time. The F-1 had quite a few glitches during its development,
especially in the area of combustion instability. In those days there was a lot
of "cut and try" in injector development.
Mike Walsh
Edward Wright
> All kidding aside. It's well known that the F-1 and J-2 engines used in the
> Saturn V ELV were considered by NASA and the rest of the aerospace community
> to be "expendable" engines, i.e. to be used for one flight only.
That is not realy true. NASA considered using the F-1 engine on the
Shuttle flyback booster stage, Phil Bono and others proposed using J-2
engines for various reusable vehicles, and J-2 engine components were
used in the linear aerospike engine built by Rocketdyne for the X-33.
> And because they were expendable, they were conservatively designed to be relatively
> inexpensive to manufacture. The average manufacturing cost was about $10M
> for the F-1 and $7.5M for the J-2 (in $Y2K). The chamber pressure was
> relatively low (about 1000 psi for the F-1 and 763 psi for the J-2) as were
> the turbopump speeds (5500 rpm for the F-1, 8,000 rpm for the J-2 LOX pump
> and 26,000 rpm for the J-2 LH2 pump).
Why do you assume low chamber pressure and turbopump speeds make an
engine non-reusable?
> Of course these engines had to be
> capable of multiple firings in order to get through the ground test
> certification wicket. In fact, these certification tests showed that the
> F-1 and J-2 production engines were about as reusable as the SSME is today
> (20 missions)
Exactly. So, whatever made these engines cheaper to manufacture, it
obviously was not non-reusability.
> You may remember the Mercury/Redstone, Mercury/Atlas and Gemini/Titan (not
> very many people do). The Mercury and Gemini astronauts did ride ELVs with
> production engines that had not been fully test fired before, except
> possibly for short 5 second burps on the pad. That's why they call it "The
> Right Stuff." If and when Lance Bass gets his economic act together and
> rides the Soyuz to the ISS, he will be riding an ELV with production engines
> that have not been fired before.
Why do you say that? According to my sources, the Russians do at least
five acceptance test firings before they use an engine on an ELV.
>> NASA has considered using the Shuttle as a crew rescue vehicle,
too.
>> It might not be a bad idea, all things considered. However, it
would
>> not make the Shuttle any cheaper.
>
> The operative word here is "assured" as in Assured Crew Rescue Vehicle
> (ACRV). The shuttle pre-flight processing time averages about 115 days, far
> to long to consider using it as a reliable crew rescue vehicle.
I fail to see your point. X-38 might 115 days of processing time.
Given the expected flight rate, however, that is not a real concern.
It's not as if NASA plans to wait until there's an emergency, then
prep the CRV for launch.
> According to the X-38/CRV folks, they can develop a full-size version
> carrying 6 persons and some small amount of cargo for about $500M and
> produce a fleet of 3 or 4 production vehicles for under $1.5B in today's
> dollars.
And you believe them?
The X-38 team has already spent $460 million and says it needs another
$50 million to get the unmanned X-38 ready for orbital flight test.
(http://www.chron.com/cs/CDA/story.hts/space/1444688)
As recently as March of 2000, the NASA Inspector General was saying
that the budget was only "$124.3 million for the X‑38 segment
and $952 million for the CRV segment."
(http://www.fas.org/spp/civil/congress/2000_h/000316-gross_031600.htm)
The CRV segment of the program hasn't even started yet. These figures
mean that X-38 is already way over budget.
> A few numbers to put that into perspective (all in $Y2K, see my
> book for details):
>
> F-1 engine development: $769M
> J-2 engine development: $389M
How do these figures put X-38 into perspective? The only way to put
the program into perspective is to compare the cost of X-38 with the
benefits. The fact that past programs cost more does not make X-38
worth more.
> Assuming that we can believe John Muratore's people who made the X-38/CRV
> cost estimates,
I don't.
> it appears that their little X-38/CRV vehicle is a bargain
> compared to the $14B that NASA paid to develop the orbiter and the ~ $20B
> spent to develop the original shuttle.
No, it simply means that none of those vehicles were bargains.
>> Well, that's one possible implementation of a CRV. That's one of
>> NASA's biggest problems. They like to specify solutions rather than
>> simply stating their actual requirements and allowing the market to
>> determine a solution. Until they start to do that, NASA's costs
will
>> never come down appreciably.
>
> Re: costs. See above for the numbers.
I've seen the numbers. Billions to develop X-38/CRV and modify the
EELV to carry it. Hundreds of millions per flight to launch it. Just
to replace a few Soyuz flights that cost tens of millions of dollars
apiece. No, Ray, this is no bargain.
>> That begs the question. If that's try, why have previous ELVs been
so
>> expensive to develop and operate? What would you do differently to
>> reduce costs, and how are you going to reduce costs enough to get a
>> decent return on the vehicle that's only going to fly four times a
>> year? (Don't say you don't need to worry about return because the
>> government is going to provide the money. You still need to
consider
>> the cost of money if you want to do a proper accounting.)
>
> Re: cost. See the numbers cited above.
Non sequitar. I asked you why previous ELVs have been so expensive and
why you think a new one will be cheaper. You told me to look at the
numbers, which merely show that previous ELVs were expensive.
>>> From what I can discern of the current SLI activity, some of those
folks are
>>> coming to a similar conclusion. And I think that the Delta IV
folks at
>>> Boeing, the Atlas V troops at Lockmart, the guys and gals at
Ariane V, and,
>>> last but not least, the Proton folks at Energia and Khrunichev are
tuning in
>>> to this way of handling the ETO segment of manned spaceflight.
>> It's hardly surprising that companies come to the conclusion that
>> their products are better than anybody else's. I seriously doubt
NASA
>> will consider Ariane or Proton for SLI, however.
>
> Didn't mean to imply that NASA would do that. But there's no doubt that,
> with the Hermes experience under their belt, the Ariane folks still have a
> gleam in their eye to do manned Ariane V launches.
So? Since when have the Europeans been known for making sound economic
decisions? You are using the "Johnny does it" argument. Just because
Johnny does it doesn't mean it's right.
>> Um, so? That's more than the gross weight of a DC-3, and that was
the
>> primary American airlifter during the largest war of the 20th
Century.
>>
>>> What is needed is a cost-effective ELV with about 60,000 to 70,000
>>> pound capability to the ISS (see chapters 27 and 56 of my book).
>>
>> Why? Once the last ISS module is in orbit, you don't need
60,000-pound
>> packages to deliver beans and bacon.
> ISS is not the Final Goal of human spaceflight. You need to broaden your
> perspective, to extend your time horizon, and to think more ambitiously.
Huh? Where did that come from? You said "60,000 to 70,000 pound
capability to ISS." To me, that indicates you were talking about ISS.
The only way to do projects that are more ambitious than ISS is to
concentrate on bringing costs down, not building bigger rockets. World
War II was a great deal more ambitious than ISS (all hype about "the
biggest space construction project" notwithstanding), and as I said,
that was supported by a fleet of tiny airlifters (by modern standards)
making frequent flights.
>>>> Minimize the number of production lines? More than we've done
>>>> already? Aerospace consolidation hasn't reduced the cost of jet
>>>> fighters. What leads you to believe it will reduce the cost of
> space
>>>> transportation?
>>>
>>> This is a lengthy subject having to do with launch vehicle
versatility,
>>> design flexibility, and budgetary survivability (see the reference
cited
>>> above for details).
>>
>> That doesn't answer the question. Can you give me examples to show
>> that defense consilidation has actually saved money?
>
> Not talking about defense consolidation. I'm referring to synergism,
> modularity and multi-use flight hardware to support a concept for a space
> transportation infrastructure, the idea for which dates back to the start of
> the manned spaceflight era and is associated with visionaries like Wernher
> von Braun and George Mueller (see chapters 27 and 56 in my book) .
I assume you know that George Mueller has spent the past few years
working on a medium-sized RLV. I also assume you know von Braun
originally planned for his moon rocket to be completely reusable, and
it was only time pressure that forced him to compromise.
However, you said "minimize the number of production lines." I don't
see what that has to do with synergism, modularity, or multi-use
flight hardware. We have all of those things in aviation, yet we have
many more production lines than we do in the space industry. We had
even more in the past, during the period when aviation was making its
greatest progress. I'm not sure when von Braun and Mueller said we
should minimize the number of production lines, but if they did, what
makes you assume they were right?
Michael Walsh
Edward Wright wrote:
> "
>
> > You may remember the Mercury/Redstone, Mercury/Atlas and Gemini/Titan (not
> > very many people do). The Mercury and Gemini astronauts did ride ELVs with
> > production engines that had not been fully test fired before, except
> > possibly for short 5 second burps on the pad. That's why they call it "The
> > Right Stuff." If and when Lance Bass gets his economic act together and
> > rides the Soyuz to the ISS, he will be riding an ELV with production engines
> > that have not been fired before.
>
> Why do you say that? According to my sources, the Russians do at least
> five acceptance test firings before they use an engine on an ELV.
You better supply a source for those five acceptance firings that you
claim the Russians do on every engine on an ELV.
Otherwise I don't believe it. It just doesn't sound reasonable to me.
Of course, I could be wrong.
Mike Walsh
Edward Wright
> You better supply a source for those five acceptance firings that you
> claim the Russians do on every engine on an ELV.
I would refer you to G. Harry Stine, but....
> Otherwise I don't believe it. It just doesn't sound reasonable to me.
You think it's reasonable to put passengers on a vehicle whose engine
has never been run? Remind me not to ride in any plane you built. :-)
It's amazing what passes for reasonable in the space business.
Edward Wright
> I believe you are missing a point. The F-1 and J-2 engines were not designed to
>
> be inexpensive to manufacture. They were representative of the highest
> technology
> available at the time. The F-1 had quite a few glitches during its development,
>
> especially in the area of combustion instability. In those days there was a lot
>
> of "cut and try" in injector development.
Maybe I missed the point, too, but I thought Ray was commenting on how
*in*expensive the F-1 and J-2 were, not how expensive. $10 million in
FY2000 dollars does not seem exhorbitant for an engine the size of the
F-1. Unless, of course, you're silly enough to use it once and throw
it away. :-)
Michael Walsh
Edward Wright wrote:
My point was that for that time period the F-1 and J-2 engines were
not only high technology for the time period but not particularly inexpensive
to develop and build.
Whether or not things deteriorated in the capability to produce
cost effective engines was not my point. I suspect that part of the
"low cost" of the F-1 and J-2 engines is produced by a bit
of creative accounting.
Things like that happen with government projects and since it
is normally not something used to defraud investors it gets
over-looked. It is usually a way to make something look
better than it really is.
Mike Walsh
Michael Walsh
Edward Wright wrote:
> Michael Walsh <mp1w...@Adelphia.net> wrote in message news:<3D77FF8D...@Adelphia.net>...
>
> > You better supply a source for those five acceptance firings that you
> > claim the Russians do on every engine on an ELV.
>
> I would refer you to G. Harry Stine, but....
I don't believe he was your source.
> > Otherwise I don't believe it. It just doesn't sound reasonable to me.
>
> You think it's reasonable to put passengers on a vehicle whose engine
> has never been run? Remind me not to ride in any plane you built. :-)
>
> It's amazing what passes for reasonable in the space business.
I have not built any planes, so don't worry. Stay off of old
Atlas missiles.
I would believe that a test firing is a good thing to do before a test
flight, but five acceptance firings on a single engine sounds like over-kill.
If I remember correctly, you said in post some months ago that the
Russians fired each engine for greater than the operational design
time of engine operation. That doesn't make sense to me.
I am not doubting that you have a reasonably good source, but I
can't help wondering if you aren't confusing the firing time on each
individual engine with the amount of test time on a new engine
configuration.
I note that "not making sense to me" doesn't necessarily mean
it didn't happen and since I am working from memory I may have
not correctly stated your earlier posts.
Mike Walsh
Earl Colby Pottinger
> An SSTO designed for low ops costs could easily achieve dramatic savings
> over shuttle, which was designed in response to an interconnected web of
> bizarre and contradictory requirements, many having nothing to do with
> spaceflight, and the most important ones (related to pork) never written
> down or publicly expressed. Ed Wright likes to say that the primary
> mission of shuttle is to employ some 30,000 people, and he's got a good
> point.
>
> .......Andrew
And in as many states as possible at the same time.
Earl Colby Pottinger
--
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