The Excellence of the Shuttle System
Ken S. Tucker
The orbiter part of the shuttle is a great machine
and has never failed (big time). The two catastophes
are from the SRB and the HO tank, and these appear
to be because of mismanaging risk, and ignoring
problems that are bound to show up in high
performance vehicles rather than any major flaw.
The basics physics of the shuttle system is ingenius.
The 2 stage craft consists of big dumb SRB's +
the 2nd stage engines useful in the first stage, and
then followed by a high ISP smart 2nd HO stage.
(A small 3rd impulse from the orbiter internal
propellant may be called a 3rd stage).
Suppose this system was scaled down to
one third size, so only one main HO engine
was on a Mini Orbiter, (or multiple smaller
engines). And this *man-rated* vehicle
(1/1000 failure rate) is used for shuttling
mainly crew (with some supply load) to LEO.
The scaled down cargo bay area would be
replaced by a crew/cargo compartment,
with the cargo bay doors replaced by a
docking airlock. I'm thinking something the
size of a business jet or so.(for some missions,
this compartment would contain extra propellant
- possibly permitting the craft to go to geosynch
or beyond if necessary, unmanned or lightly
manned, possibly for rescue).
This craft would be able to service the Hubble
and other space based scopes.
The 2 main SRB's, might be replaced by
six or eight mini SRB's on the HO tank.
Mini-SRB's are much easier to mass produce.
Reusablity economics might permit recovery
of SRB's and then refueling with a single grain each,
eliminating the tedium of "O" rings and segments,
something that does not scale safely or cheaply.
If economical, it may be possible to make the
HO tank recoverable, that's bean counting.
It would be practical to use a similiar system to
get big dumb payloads (like the space-ships)
that will ferry personel from Earth to the Moon
into orbit, although not necessarily man-rated,
(1/50 failure rate).
In this case, using the current shuttle components,
replace the orbiter with the payload, but make
the 3 main engines detach and re-enter (protected
by a heat shield) for re-use - unless mass production
makes it cheaper to make these disposable - again
a bean counting decision - but the bean counting
may ultimately permit or kill the program, so it
must be respected = need to watch the bottom line.
This respects the failure rate profiles vs economics.
It's not easy to fly heavy dumb payloads in man-rated
vehicles as the Shuttle system was expected to do.
It's safer to rely on the SOP of Earth Orbit rendevous,
to transfer crew to Moon bound Space-ships.
This plan broadly supports the Bush Space Initative,
in accord with NASA's experential profile, in away
that is probably palatable to the taxpayer's pleasure.
Regards
Ken S. Tucker
dave schneider
[...]
> Suppose this system was scaled down to
> one third size
[...]
Some of the OSP ideas were broadly similar, but OSP was to take
advantage of a "mass-produced" booster (D4, A5 -- or more properly,
DIV, A5 -- the ultimate Delta machine and the Ultimate Atlas machine).
I expect CEV will also do this.
One disadvantage to a smaller winged orbiter, btw, is one that Henry
and others have pointed out: the larger orbiter has a better
energy/surface figure because you're supporting the mass with more
area (scaling laws), and this means the smaller vehicle has tougher
TPS requirements for vulnerable areas like leading edges.
Capsules dodge the leading edge thing, so the scaling laws don't hurt
as much for them.
/dps
Zoltan Szakaly
> The excellence of the shuttle system.
>
> The orbiter part of the shuttle is a great machine
> and has never failed (big time). The two catastophes
> are from the SRB and the HO tank, and these appear
> Regards
> Ken S. Tucker
The shuttle is an excellent and reliable system. Two failures of about
100 flights is pretty good reliability. There are two problems with
the shuttle.
1. The lack of plan B in case of failure. During launch there should
be an apollo style LET system to remove the cabin from the fireball.
During reentry there should be ejection seats as a safety backup.
These are not hard to implement.
2. The utter stupidity of shuttling a heavy vehicle up and down when
the cost of launch is so high. The only thing the shuttle is good for
is bringing something back from orbit. This is not something we need.
We should use the existing shuttles to continue launching payloads
while we develop a vehicle like Buran where we could replace the
orbiter with some other payload. After all we do have a heavy launch
vehicle. The shuttle system without the shuttle.
Zoltan
Gordon D. Pusch
> The shuttle is an excellent and reliable system. Two failures of about
> 100 flights is pretty good reliability.
Would you tolerate a car or a computer system that failed catastrophically
and killed you after an average of 100 trips or 100 reboots ???
> There are two problems with the shuttle.
>
> 1. The lack of plan B in case of failure. During launch there should
> be an apollo style LET system to remove the cabin from the fireball.
> During reentry there should be ejection seats as a safety backup.
> These are not hard to implement.
...However, the additional mass will cut into your payload, and the
additional expense will cut into your budget. You pays your money,
and you takes your engineering trade-offs.
BTW, when was the last time you saw either an ejection system
or an escape capsule on _any_ type of cargo aircraft ???
-- Gordon D. Pusch
perl -e '$_ = "gdpusch\@NO.xnet.SPAM.com\n"; s/NO\.//; s/SPAM\.//; print;'
Greg D. Moore (Strider)
"Gordon D. Pusch" <g_d_pusch_remo...@xnet.com> wrote in message
news:giu12k2...@pusch.xnet.com...
>
> BTW, when was the last time you saw either an ejection system
> or an escape capsule on _any_ type of cargo aircraft ???
To be fair, I think C-130s have some sort of escape system. :-)
Karl Hallowell
If I understand the original poster, he suggests scaling the entire
orbiter down rather than just the wings. In that case, the surface
area per mass should increase. And if I understand you, that means the
energy (dissipation?) per surface area should decrease.
Karl Hallowell
kha...@hotmail.com
Joann Evans
>
> dyna...@vianet.on.ca (Ken S. Tucker) wrote in message news:<2202379a.04011...@posting.google.com>...
> > The excellence of the shuttle system.
> >
> > The orbiter part of the shuttle is a great machine
> > and has never failed (big time). The two catastophes
> > are from the SRB and the HO tank, and these appear
> ...
> > Regards
> > Ken S. Tucker
>
> The shuttle is an excellent and reliable system. Two failures of about
> 100 flights is pretty good reliability. There are two problems with
> the shuttle.
Don't you ever consider designing commercial/military aircraft,
please!
And the argument that 'it's a spaceship' doesn't change mine.
> 1. The lack of plan B in case of failure. During launch there should
> be an apollo style LET system to remove the cabin from the fireball.
So you now need to redesign the cabin to come away by design...how
much does this weigh? Are parachutes pratical? And you also must now be
able to survive coming down on land or water...
> During reentry there should be ejection seats as a safety backup.
Unless you have re-entry worthy enclosures similar to the bailout
system of the B-70, what does ejection get you during re-entry? You just
toast seperately from the ship.
> These are not hard to implement.
That's very easy to say...
> 2. The utter stupidity of shuttling a heavy vehicle up and down when
> the cost of launch is so high.
It's not the weight of the vehicle that causes that. What does a
fully fueled 747 weigh?
> The only thing the shuttle is good for
> is bringing something back from orbit. This is not something we need.
>
> We should use the existing shuttles to continue launching payloads
> while we develop a vehicle like Buran where we could replace the
> orbiter with some other payload.
The idea's not new, we call it Shuttle-C. Some like it, some don't.
and it isn't necessairily cheap, either.
> After all we do have a heavy launch
> vehicle. The shuttle system without the shuttle.
>
> Zoltan
--
You know what to remove, to reply....
Joann Evans
>
> "Gordon D. Pusch" <g_d_pusch_remo...@xnet.com> wrote in message
> news:giu12k2...@pusch.xnet.com...
> >
> > BTW, when was the last time you saw either an ejection system
> > or an escape capsule on _any_ type of cargo aircraft ???
>
> To be fair, I think C-130s have some sort of escape system. :-)
But military C-130 crews also have to consider that someone may be
out to actively shoot them down one day.
Even with recent events, except for possibly adding some
countermeasures for shoulder-fired terrorist weapons, this isn't a
normal concern for most cargo aircraft...or even the shuttle.
ed kyle
>
> The orbiter part of the shuttle is a great machine
> and has never failed (big time). The two catastophes
> are from the SRB and the HO tank, and these appear
> to be because of mismanaging risk, and ignoring
> problems that are bound to show up in high
> performance vehicles rather than any major flaw.
>
The shuttle design, including the design of the
orbiter itself, has a fundamental flaw. There is
no escape option for the crew in the event of a
catastrophic failure during the first couple of
minutes of flight (the SRB phase). This design
was anything but excellent. Arrogant, foolish,
or stupid are better descriptive terms. The
shuttle designers had access to years of solid
and liquid propulsion system flight history.
They should have full well known that even the
most successful launch systems (like Minuteman)
failed 1-2% of the time - and that the failures
often occurred during the first few minutes of
flight.
- Ed Kyle
Sander Vesik
> But military C-130 crews also have to consider that someone may be
> out to actively shoot them down one day.
space debris does that for space vehicles - esp ones with wings.
>
> Even with recent events, except for possibly adding some
> countermeasures for shoulder-fired terrorist weapons, this isn't a
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The weapons are not in any particular way exclusive or specific to
terrorists so its dishonest to call them "shoulder-fired terrorist
weapons". How do you classify stringers, btw? They have used by
terrorists to down far more aircarft than the ones in use in Iraq.
> normal concern for most cargo aircraft...or even the shuttle.
It appears to be a concern for normal passenger aircraft occasionaly.
--
Sander
+++ Out of cheese error +++
James Graves
>> During reentry there should be ejection seats as a safety backup.
>
> Unless you have re-entry worthy enclosures similar to the bailout
>system of the B-70, what does ejection get you during re-entry? You just
>toast seperately from the ship.
That's pretty much the problem. You're way up high, going way too fast,
for any effective bailout system.
You'd have to design a completely separate re-entry system.
In case you haven't seen it yet, Newsday had a gripping account of the
final few minutes of Columbia:
http://www.newsday.com/news/health/ny-hscov0127,0,442476.story
[... deleted ...]
> The idea's not new, we call it Shuttle-C. Some like it, some don't.
>and it isn't necessairily cheap, either.
>
>> After all we do have a heavy launch
>> vehicle. The shuttle system without the shuttle.
There are many routes to cheaper and safer access to LEO. None of those
paths, however, start with the Shuttle program.
James Graves
Eric Fenby
"James Graves" <ans...@typhoon.xnet.com> wrote in message
news:bva5vn$680$1...@flood.xnet.com...
Aluminium is a very cheap material but has to be inappropriate for building
the Shuttle's wings etc.
If the Shuttle had been constructed out of titanium, which has a 2000c
degree melting point instead of the 400-C of aluminium, how much lower would
it have been before breakup?
Perhaps a titanium wing structure with the interior box sections filled in
with a lightweight refractory foam to exclude the superheated gasses?
Titanium's STW ratio is favourable enough for fighter aircraft so why not?
Henry Spencer
Eric Fenby <ericfenby...@btopenworld.com> wrote:
>Aluminium is a very cheap material but has to be inappropriate for building
>the Shuttle's wings etc.
Aerospace aluminum alloys are not all that cheap, actually...
>If the Shuttle had been constructed out of titanium, which has a 2000c
>degree melting point instead of the 400-C of aluminium, how much lower would
>it have been before breakup?
Possibly not any lower at all.
First, let's get the numbers right. Aluminum melts at 659degC, and
titanium at 1670degC. Moreover, those may not be the relevant numbers:
the highest *usable* temperature for a structural material is typically
rather lower, because most metals are quite weak by the time they're about
to melt. Aluminum alloys are generally considered structurally useful up
to 250-300degC, titanium alloys up to 500-600degC. The number we care
about is probably somewhere in between the usable temperature and the
melting point.
Now, as for a titanium Columbia...
For one thing, the outer thermal protection would have been different --
generally thinner -- since the interior could run hotter. (The big
advantage cited for titanium structure, when NASA was considering what
material to use, was that the development of the tiles etc. would be
easier.) So the hole might well have been bigger. Also, the structure
inside would have been hotter to begin with, since the whole point of
using titanium would have been to permit that.
Then too, the titanium would have been considerably thinner, since it's a
stronger (and denser) material.
Also, the combination of thinner material and titanium's *much* lower
thermal conductivity makes a titanium structure much more vulnerable to
localized overheating, since it's not nearly as good at conducting heat
away from a hot spot.
Put all this together, and it's not clear that you get much advantage,
especially given the horrendous conditions involved. This wasn't a case
of aluminum being almost good enough.
Finally, even holding together a little bit longer confers no real
advantage in such a situation. There would still be no realistic chance
of the wing holding together all the way to the ground (which is what it
takes to do a successful bailout from an orbiter -- the last man out
leaves at quite low altitude).
>Perhaps a titanium wing structure with the interior box sections filled in
>with a lightweight refractory foam to exclude the superheated gasses?
If you want to spend considerable weight on improving tolerance to faults
in the thermal protection, probably much the most effective way would be
to forget screwing around with the structure, and put a layer of ablator
behind the leading edge.
Although I'm not up on everything that's done in advanced materials, I'm
not aware of any "lightweight refractory foams". Certainly not ones that
were available in the early 1970s.
>Titanium's STW ratio is favourable enough for fighter aircraft...
Fighter aircraft are invariably mostly aluminum. The only exceptions are
the MiG-25 and MiG-31, which are steel (heat-resistant but very heavy).
The only operational titanium aircraft have been a few specialized
high-speed types, notably the Blackbirds.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. | he...@spsystems.net
Joann Evans
>
> Joann Evans <bon...@frontiernet.net> wrote:
>
> > But military C-130 crews also have to consider that someone may be
> > out to actively shoot them down one day.
>
> space debris does that for space vehicles - esp ones with wings.
>
> >
> > Even with recent events, except for possibly adding some
> > countermeasures for shoulder-fired terrorist weapons, this isn't a
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> The weapons are not in any particular way exclusive or specific to
> terrorists so its dishonest to call them "shoulder-fired terrorist
> weapons".
Correct. But they are starting to be increasingly used by
terroriists. Thus the prospect of countermeasures on civil aircraft.
> How do you classify stringers, btw? They have used by
> terrorists to down far more aircarft than the ones in use in Iraq.
It's a 'terrorist weapon' if a terrorist uses it. This is exactly why
I did not simply say 'shoulder fired weapons.'
> > normal concern for most cargo aircraft...or even the shuttle.
>
> It appears to be a concern for normal passenger aircraft occasionaly.
Right, but we still don't equip them with ejection systems. Greg's
point was that the C-130 is an example of a cargo plane that has this
feature. *My* point was that it's still a military aircraft whose
designers and operators know is mre likely to be operated in situations
where it may come under fire, as opposed to ejection primairily
motivated by catastrophic failure.
> --
> Sander
>
> +++ Out of cheese error +++
Joann Evans
[snip]
> > The idea's not new, we call it Shuttle-C. Some like it, some don't.
> >and it isn't necessairily cheap, either.
> >
> >> After all we do have a heavy launch
> >> vehicle. The shuttle system without the shuttle.
>
> There are many routes to cheaper and safer access to LEO. None of those
> paths, however, start with the Shuttle program.
Those that don't like the Shuttle-C concept seem to agree with you.
James Graves
>Aluminium is a very cheap material but has to be inappropriate for building
>the Shuttle's wings etc.
Given the design choices, it was fine. The shuttle was never designed
to survive a significant breach in its TPS. Wether or not that was a
good design decision is a discussion for another day.
>If the Shuttle had been constructed out of titanium, which has a 2000c
>degree melting point instead of the 400-C of aluminium, how much lower would
>it have been before breakup?
Answer: Not much lower. From the Newsday article:
"But with the boundary layer disrupted, the temperature of the
atoms and molecules blasting into the wing probably exceeded
8,000 degrees near the leading edge breach itself."
>Perhaps a titanium wing structure with the interior box sections filled in
>with a lightweight refractory foam to exclude the superheated gasses?
The foam would be blown away shortly before the wing melted and broke
off. They were still at hypersonic when big chunks of the shuttle were
breaking off.
>Titanium's STW ratio is favourable enough for fighter aircraft so why not?
Titanium is a fantasically great material, from an aircraft designer's
perspective.
>From an aircraft _builder's_ perspective, it isn't so nice.
For an example of this, check the TV show Nova, which recently aired a
program on the JSF competition. Boeing had lots of "fun" with a
specially machined titanium bulkhead that tied together the whole
aircraft. The material is very, very difficult to work with.
And then there's the question of how much it costs...
James Graves
Zoltan Szakaly
I quote from the above referenced article:
>>>>>>
But investigators were struck by the way the crew modules of both
Challenger and Columbia broke away relatively intact. The
survivability study concluded relatively modest design changes might
enable future crews to survive long enough to bail out.
<<<<<<
A properly designed and built crew module could separate from the
orbiter at the bulkheads (perhaps primacord or other explosive
separation system). It could subsequently decelerate by airdrag or fly
under rocket power then land using parachutes.
Zoltan
Mike Miller
> That's pretty much the problem. You're way up high, going way too fast,
> for any effective bailout system.
Actually, quite a few bailout systems have been proposed. A derivative
of the XB-70 ejection seat was among them.
http://www.astronautix.com/craft/egress.htm
> You'd have to design a completely separate re-entry system.
And that was exactly what the bailout systems included.
A list of systems:
http://www.astronautix.com/craft/mancraft.htm
Specific re-entry capable examples that might fit into an ejection
seat-sized package:
http://www.astronautix.com/craft/encap.htm
http://www.astronautix.com/craft/geleraft.htm
http://www.astronautix.com/craft/moose.htm
http://www.astronautix.com/craft/paracone.htm
http://www.astronautix.com/craft/saver.htm
There's quite a number of capsule concepts, too, but those don't
retrofit as well into the shuttle.
Mike Miller, Materials Engineer
Ken S. Tucker
If you look at the Columbia ascent problem, the left
wing became the hazard by yawing and rolling the
orbiter beyond safe conditions. At that point it would
be better to discard both wings (explosive bolts) and
return within the remaining capsule. I would think the
wingless orbiter would extend it's flight to well beyond
KSFC, giving the crew a bailout option over the
Atlantic, possibly including some light-weight para-
chute breaking on the orbiter.
It might be possible to bring a wingless orbiter down
into the Atlantic by modest parachute without
significant trauma to the crew, as the X-B70 and
later the proposed B1-A was initially to incorporate.
((IIRC this was scrapped on the B1-A because it
added ~5,000 lbs)).
Regards Ken S. Tucker
PS: Thank you all for responding to my OP.
Henry Spencer
Ken S. Tucker <dyna...@vianet.on.ca> wrote:
>If you look at the Columbia ascent problem, the left
>wing became the hazard by yawing and rolling the
>orbiter beyond safe conditions. At that point it would
>be better to discard both wings (explosive bolts) and
>return within the remaining capsule. I would think the
>wingless orbiter would extend it's flight to well beyond
Uh, no, without lift it would have gone down much earlier. And the
wingless body would probably have broken up due to excessive G-loads and
heating; the major role of the wings during reentry is to keep the orbiter
up at high altitudes, in thin air, for gentler deceleration and lower
temperatures.
> It might be possible to bring a wingless orbiter down
>into the Atlantic by modest parachute without
>significant trauma to the crew...
I don't think you have any grasp of how much the orbiter, even without its
wings, *weighs*. No. Not with any parachute ever built.
Gordon D. Pusch
> If you look at the Columbia ascent problem, the left
> wing became the hazard by yawing and rolling the
> orbiter beyond safe conditions. At that point it would
> be better to discard both wings (explosive bolts) and
> return within the remaining capsule. I would think the
> wingless orbiter would extend it's flight to well beyond
> KSFC, giving the crew a bailout option over the
> Atlantic,
...Except that without wings, the bare orbiter fuselage would be unstable,
and the re-entry plasma would be eating through the unprotected scars left
by the wing roots. Cutting loose the crew cabin would result in similar
stability and thermal protection problems...
dave schneider
> d_sch...@emulex.com (dave schneider) wrote:
[...]
> > One disadvantage to a smaller winged orbiter, btw, is one that Henry
> > and others have pointed out: the larger orbiter has a better
> > energy/surface figure because you're supporting the mass with more
> > area (scaling laws), and this means the smaller vehicle has tougher
> > TPS requirements for vulnerable areas like leading edges.
> >
> > Capsules dodge the leading edge thing, so the scaling laws don't hurt
> > as much for them.
>
> If I understand the original poster, he suggests scaling the entire
> orbiter down rather than just the wings. In that case, the surface
> area per mass should increase. And if I understand you, that means the
> energy (dissipation?) per surface area should decrease.
>
I would hope he was scaling the whole thing down, as the orbiter is
much too heavy for any smaller wings! And because of various volume
considerations, a scaled down orbiter doesn't get light enough to
maintain the current area/mass ratio -- or else I'm way off in
remembering Henry's comments from 6-10 months ago!
/dps
Kelly St
The hell it is!!! Thats good for a X plane (well almost - the X-15 I know had
twice that rate) but for a frieghter its rediculas!!
Shuttle was to be a safe relyable low cost system to get poeople and cargo to
and from space. Its none of the above, even compared to expendables of the
day.
Kelly Starks
Kel...@aol.com
"Humans are a race of compassionate predators."
Kelly St
>> or an escape capsule on _any_ type of cargo aircraft ???
>
>To be fair, I think C-130s have some sort of escape system. :-)
not that I ever saw or heard of?
Kelly St
>> The shuttle is an excellent and reliable system. Two failures of about
>> 100 flights is pretty good reliability. There are two problems with
>> the shuttle.
>
> Don't you ever consider designing commercial/military aircraft,
>please!
I think airliners are designed to have a crash per few million flights, not
every few dozen.
After all their are thousands of flights per day, and few crashes per year.
> And the argument that 'it's a spaceship' doesn't change mine.
>
>> 1. The lack of plan B in case of failure. During launch there should
>> be an apollo style LET system to remove the cabin from the fireball.
>
> So you now need to redesign the cabin to come away by design...how
>much does this weigh? Are parachutes pratical? And you also must now be
>able to survive coming down on land or water...
At least a few tons I imagin.
>=====
>
>> 2. The utter stupidity of shuttling a heavy vehicle up and down when
>> the cost of launch is so high.
>
> It's not the weight of the vehicle that causes that. What does a
>fully fueled 747 weigh?
True. Shuttle costs are largely due to the high labor costs needed to prep the
shuttle for launch. These are due to design shortcomings, not weight.
>> The only thing the shuttle is good for
>> is bringing something back from orbit. This is not something we need.
>>
>> We should use the existing shuttles to continue launching payloads
>> while we develop a vehicle like Buran where we could replace the
>> orbiter with some other payload.
>
> The idea's not new, we call it Shuttle-C. Some like it, some don't.
>and it isn't necessairily cheap, either.
It could be if It eliminates the bulk of the systems that require the high
labor hours per flight.
>> After all we do have a heavy launch
>> vehicle. The shuttle system without the shuttle.
>>
>> Zoltan
>
>