Apollo J mission LMs
KenworthyD
The weight problems with early Apollo LMs are well documented within this group
and elsewhere - the recent Apollo 10 LM landing thread springs to mind.
Given that the J missions carried rovers, returned more moon rocks than the
early landing missions, and presumably carried more consumables, what happened
to the weight issue?
Was the upgrading of the DPS sufficient to deal with this increase, or were
'trade-off' savings made elsewhere in the LM?
Also, were there issues to be addressed with the Saturn launch vehicle, or was
there sufficient excess payload capacity to handle this increase?
Thanks in anticipation, and apologies if there's a simple RTFM answer to this
one!
Dave Kenworthy
Cb61
The flight profile was changed so the entire stack - CSM + LM - went down to
50K feet for the start of powered descent, using the CSM engine instead of
the LM. The weight difference was made up for in fuel carried by the LM (less).
Later versions of the Saturn V made considerably more than the advertised first
stage 7.5M lbs thrust so more stuff could get lobbed into space. I don't
remember the exact numbers.
Henry Spencer
In article <199805221306...@ladder03.news.aol.com>,
KenworthyD <kenwo...@aol.com> wrote:
>Given that the J missions carried rovers, returned more moon rocks than the
>early landing missions, and presumably carried more consumables, what happened
>to the weight issue?
Many changes. The Saturn V itself was souped up slightly, by tweaking the
engines and deleting unnecessary bits of hardware, based on growing flight
experience. Flight experience also permitted thinning down fuel margins
in the Saturn V stages. The CSM did more maneuvering, including taking
the LM down to the point of Powered Descent Initiation, saving LM fuel.
LM fuel margins were reduced as confidence in landing guidance and site
selection grew. The performance of the LM descent engine was improved by
lengthening the nozzle (after it became clear that the LM had more ground
clearance than it needed, because landings were gentler than expected) and
making other small changes. The descent-stage fuel tanks were enlarged
slightly, to more fully use the space inside the descent stage.
--
Being the last man on the Moon | Henry Spencer
is a very dubious honor. -- Gene Cernan | he...@zoo.toronto.edu
Paul Michael Brown
Henry Spencer, informative as always, recently explained how the heavier
J-Series LMs were boosted:
: Many changes. The Saturn V itself was souped up slightly, by tweaking the
: engines and deleting unnecessary bits of hardware, based on growing flight
: experience. [Remainder of cogent post deleted.]
Here's a hypothetical for the "what-if" fans here. Suppose, for whatever
reason, the Saturn V has remained in production for the past 30 years.
Suppose further that during that time, lighter materials such as advanced
alloys, composite structures and miniaturized electronics had been
incorporated into the design. Finally, assume that the propulsion system
had remained the same. Anybody care to hazard a guess in respect of how
much the Saturn V's payload would have increased?
Dwayne Allen Day
Paul Michael Brown (pa...@mirror.his.com) wrote:
: Here's a hypothetical for the "what-if" fans here. Suppose, for whatever
: reason, the Saturn V has remained in production for the past 30 years.
: Suppose further that during that time, lighter materials such as advanced
: alloys, composite structures and miniaturized electronics had been
: incorporated into the design. Finally, assume that the propulsion system
: had remained the same. Anybody care to hazard a guess in respect of how
: much the Saturn V's payload would have increased?
Well, I doubt that this could be answered without a very careful analysis.
Just how much did the flight electronics weigh, for instance, and how much
could they have been reduced in weight by today? You'd have to go through
it piece by piece.
There were a LOT of back of the envelope calculations for enhanced Saturn
Vs. Most of these were total pie in the sky proposals (one has to ask how
serious a proposal is when it fills up only a couple of sheets of
paper--the devil is in the details).
However, one enhancement that would have had a very good chance of making
it into the flight vehicles was the upgrading of the engines from F-1 to
F-1A status. The F-1 had 1.5 million pounds of thrust, the F-1A had 1.8
and was tested successfully before the program was ended. Given that
first stage performance could have been increased by 1.5 million pounds of
thrust, what would this have meant for the payload that could be carried?
That's an easier and more legitimate question.
DDAY
Henry Spencer
In article <3568e...@news4.his.com>,
Paul Michael Brown <pa...@mirror.his.com> wrote:
>: Many changes. The Saturn V itself was souped up slightly, by tweaking the
>
>...Suppose further that during that time, lighter materials such as advanced
>alloys, composite structures and miniaturized electronics had been
>incorporated into the design. Finally, assume that the propulsion system
>had remained the same. Anybody care to hazard a guess in respect of how
>much the Saturn V's payload would have increased?
The assumptions are somewhat unrealistic, given that major improvements to
the engines had already been tested (for example, the 20%-hotter F-1A).
Furthermore, changes like new materials would not have been introduced
straight into the existing design, but would have gone into new versions
with other design changes like stretched tanks. A Saturn V Mark 2 would
almost certainly have had uprated engines and some degree of tank stretch,
just for starters.
A more radical possibility was replacing LOX with liquid fluorine in the
second and third stages, and with a LOX/fluorine mixture in the first
stage. (Hydrocarbon fuels need some oxygen in the oxidizer, because
fluorine doesn't cope well with the carbon content.) NASA took this idea
quite seriously at the time, as a natural growth path. And, of course,
there was also the idea of nuclear engines for the third stage and maybe
even the second stage (!). (It wasn't an accident that the NERVA people
were aiming at a J-2-class engine.)
Other side issues include the possibility of a completely-redesigned and
larger third stage -- the S-IVB was too small to make a good third stage
for Earth-to-orbit, which is why it tended to be deleted from concepts
aimed at LEO heavylift work -- and strap-ons for the first stage.
Even a relatively conservative "continue existing programs but without
major new investments" plan -- the sort of thing that *just might* have
happened if the Agnew report hadn't been so totally out of touch with
political reality -- would probably have opted for engine uprating sooner
or later, since the added payload would be helpful and the new engines
were already in the pipeline. A bit of cautious tank stretching also
seems likely. Such a plan probably *wouldn't* have changed materials,
except in entirely new structural assemblies, which would have been few
and far between; the effort needed for redesign of existing assemblies
would not have been considered worthwhile.
All that being said, returning to the original question...
New materials and lighter subsystems in the first stage would not have
helped a lot, because the dry mass of that stage just wasn't all that
influential. The second stage had already seen severe mass-reduction
efforts, because it was caught between a nearly-finished third stage and a
not-very-influential first stage, and had to bear the brunt of the attack
when a performance shortfall loomed. I think the big impact would have
been in the third stage, where mass-reduction efforts hadn't been strong
due to schedule pressure, and where dead weight counted directly against
final payload.
I don't have good numbers handy for the late-model (J-mission) Saturn V
third stages, but knocking a little bit off the early ones to allow for
incremental improvements, the dry mass of the third stage was about 32klb,
and the instrument unit on top of it weighed about 4klb. Being wildly
optimistic, say we cut the dry mass of the stage in half, and since the
IU was basically electronics, shrink it to effectively zero (it had some
structure as well, but if we don't need that to support the electronics,
we can just put the payload directly on top of the S-IVB, which we're
probably redesigning fairly drastically anyway). That would add about
20klb to the translunar payload. As flown, translunar payload was in the
vicinity of 100klb. So we're talking about a substantial improvement,
but not a truly radical one.
Dwayne Allen Day
Henry Spencer (he...@zoo.toronto.edu) wrote:
: political reality -- would probably have opted for engine uprating sooner
: or later, since the added payload would be helpful and the new engines
: were already in the pipeline. A bit of cautious tank stretching also
: seems likely.
This seems reasonable. Unfortunately, any change in the tank length
requires extensive rework of the tower to support it. The sheer size of
the Saturn then works against you--there is no such thing as a minor
redesign of a 350+ foot tower.
DDAY
Jonathan Stone
"minor" in comparison to a stretch of the VAB, perhaps?
(Henry? how much of a stretch did you envision, and how much headroom
was there in the VAB?)
jjw...@tassie.net.au
In article <3568e...@news4.his.com>,
pa...@mirror.his.com (Paul Michael Brown) wrote:
> Here's a hypothetical for the "what-if" fans here. Suppose, for whatever
> reason, the Saturn V has remained in production for the past 30 years.
> Suppose further that during that time, lighter materials such as advanced
> alloys, composite structures and miniaturized electronics had been
> incorporated into the design. Finally, assume that the propulsion system
> had remained the same. Anybody care to hazard a guess in respect of how
> much the Saturn V's payload would have increased?
Mark Wade has some details on hypothetical Saturn V upgrades dating from the
1960's at http://solar.rtd.utk.edu/~mwade/lvfam/saturnv.htm
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Henry Spencer
In article <6kcvsb$i6p$2...@nntp.Stanford.EDU>,
Jonathan Stone <jona...@DSG.Stanford.EDU> wrote:
>|> This seems reasonable. Unfortunately, any change in the tank length
>|> requires extensive rework of the tower to support it. The sheer size of
>|> the Saturn then works against you--there is no such thing as a minor
>|> redesign of a 350+ foot tower.
>
>"minor" in comparison to a stretch of the VAB, perhaps?
>(Henry? how much of a stretch did you envision, and how much headroom
>was there in the VAB?)
There was lots of headroom in the VAB, because the basic specs for the VAB
had to be fixed quite early, so design and construction could start. In
fact, they had to be fixed before anybody knew exactly how big a rocket
would go in it! (And for that matter, it was seen as a piece of long-term
infrastructure that might well handle more than one type of rocket.) So
they left plenty of extra space. Even quite drastic Saturn V stretches
would fit.
Dwayne is right that the changes to the towers (and to the VAB work
platforms) would add to the expense of tank stretches. However, small
stretches might well be accommodated with relatively minor changes --
say, moving some arms slightly rather than rebuilding the tower -- as
was done for Skylab. (Also, if you make a determined effort to move
closer to the original Complex 39 concept -- where almost all work is
done in the VAB -- that reduces the need for the towers.)
Jens A. Lerch
jona...@Kowhai.Stanford.EDU (Jonathan Stone) wrote:
>In article <6kcr9m$d0...@fozzy.nit.gwu.edu>, wayn...@gwis2.circ.gwu.edu (Dwayne Allen Day) writes:
>|> Henry Spencer (he...@zoo.toronto.edu) wrote:
>|> : political reality -- would probably have opted for engine uprating sooner
>|> : or later, since the added payload would be helpful and the new engines
>|> : were already in the pipeline. A bit of cautious tank stretching also
>|> : seems likely.
>|>
>|> This seems reasonable. Unfortunately, any change in the tank length
>|> requires extensive rework of the tower to support it. The sheer size of
>|> the Saturn then works against you--there is no such thing as a minor
>|> redesign of a 350+ foot tower.
>"minor" in comparison to a stretch of the VAB, perhaps?
>(Henry? how much of a stretch did you envision, and how much headroom
>was there in the VAB?)
If the VAB is to low for the full stack of an upgraded Saturn V, the
CSM and LEM could be attached at the launch pad, like on all Ariane
missions. The tower needs to be modified for this operation, but it
needs to be modified anyway because it is currently configured for the
Space Shuttle.
/\ Jens A. Lerch
|| fxw...@rz.uni-frankfurt.de
|| Please take a look at my Space Statistics Page at
/||\ http://www.rz.uni-frankfurt.de/~fxws326/space.htm
|||| _________________________________________________
|||| NEW: Information on Angara and Rickshaw,
^^^^ two new Russian space launch systems
Graham Nelson
In article <EtKv57.4o0%spen...@zoo.toronto.edu>, Henry Spencer
<URL:mailto:he...@zoo.toronto.edu> wrote:
>
> There was lots of headroom in the VAB, because the basic specs for the VAB
> had to be fixed quite early, so design and construction could start. In
> fact, they had to be fixed before anybody knew exactly how big a rocket
> would go in it! (And for that matter, it was seen as a piece of long-term
> infrastructure that might well handle more than one type of rocket.) So
> they left plenty of extra space. Even quite drastic Saturn V stretches
> would fit.
I wonder what will happen to the VAB when the Shuttle programme
ends? It's already far larger than needed. I doubt if anything
like VentureStar will operate from KSC, even if it's ever built...
I suppose a Shuttle-derived heavy-lift vehicle -- if there ever
is one -- might use the VAB.
But presumably it will end up as a National Monument, a cathedral
of our times.
--
Graham Nelson | gra...@gnelson.demon.co.uk | Oxford, United Kingdom
Henry Spencer
In article <ant2707041cbM+4%@gnelson.demon.co.uk>,
Graham Nelson <gra...@gnelson.demon.co.uk> wrote:
>> There was lots of headroom in the VAB, because the basic specs for the VAB
>
>I wonder what will happen to the VAB when the Shuttle programme
>ends? It's already far larger than needed. I doubt if anything
>like VentureStar will operate from KSC, even if it's ever built...
LockMart's take on that, one or two Space Access conferences ago, was
that it's cheaper to build new pads than to pay LC39's overhead costs.
(That is almost a direct quote.) Given that NASA is most unlikely to
ever get funding for a big new launcher, the shuttle is probably the
last vehicle that will use the VAB.
>But presumably it will end up as a National Monument, a cathedral
>of our times.
Seems likely, yes.
Henry Spencer
In article <6kgbs9$q5k$3...@grapool30.rz.uni-frankfurt.de>,
Jens A. Lerch <fxw...@uni-frankfurt.de> wrote:
>If the VAB is to low for the full stack of an upgraded Saturn V, the
>CSM and LEM could be attached at the launch pad, like on all Ariane
>missions. The tower needs to be modified for this operation, but it
>needs to be modified anyway because it is currently configured for the
>Space Shuttle.
Well, we were talking about alternate pasts -- continued growth of the
Saturn V, rather than a revival of same, which is unlikely -- so the
changes that have been made for the shuttle are irrelevant. To make a
Saturn revival work, you'd almost certainly have to build a new pad and
new launch platforms anyway.
Incidentally, what Jens says is correct (I think) for the earlier Arianes
but is not right for Ariane 5. Ariane 5 has two assembly buildings and a
mobile launch platform. The first building does basic assembly of the
rocket. The second puts the payload on top, inserts the pyros, fuels the
second stage, and generally does almost everything except cryo fueling and
actual launch. Rollout to the pad is only hours before launch. Once the
rollout starts, there is no access to the payload and only very limited
access to the rocket. The pad has no tower in the traditional sense, only
a low umbilical mast. This is partly a matter of efficiency -- doing all
the delicate work in better-controlled conditions -- and partly a matter
of launch safety -- minimizing the cost and complexity of the ground
systems which are located on or near the pad and hence are exposed to
damage in a launch failure.
That's also, by the way, much the way the VAB was intended to operate.
The original notion was that only the most basic final procedures would
be done on the pad. NASA psyched itself up to actually doing things that
way only once -- for Skylab, when severe cost and schedule constraints
forced the issue -- and found that it worked very well.
Graham Nelson
In article <EtMK7K.EBv%spen...@zoo.toronto.edu>, Henry Spencer
<URL:mailto:he...@zoo.toronto.edu> wrote:
>
> That's also, by the way, much the way the VAB was intended to operate.
> The original notion was that only the most basic final procedures would
> be done on the pad. NASA psyched itself up to actually doing things that
> way only once -- for Skylab, when severe cost and schedule constraints
> forced the issue -- and found that it worked very well.
Why do any work at the pad at all, other than final fuelling?
Doesn't it just increase the nuisance factor, increase the time
when the rocket is open to the weather and force you to load the
payload vertically rather than horizontally?
I suppose if the VAB were too small for two Shuttles at once,
I could see some point in getting the Shuttle out of the VAB as
fast as possible, but surely it's big enough for all four if
need be.
Michael Morton
Graham Nelson <gra...@gnelson.demon.co.uk> wrote in article
<ant272040868M+4%@gnelson.demon.co.uk>...
>
>
> Why do any work at the pad at all, other than final fuelling?
> Doesn't it just increase the nuisance factor, increase the time
> when the rocket is open to the weather and force you to load the
> payload vertically rather than horizontally?
>
>
It's interesting that ESA has gone over to the 'bare pad' idea
for Ariane 5, unlike Ariane 4 which had payload integration on
the pad. I'm guessing, but I suppose that would have been
excessively combersome when the A5 was manifested for 3 payloads.
Another (pessamistic) advantage I read was that the pad would
be more quickly and cheaply replaced if the worst happened.
--
Michael Morton
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Henry Spencer
In article <ant272040868M+4%@gnelson.demon.co.uk>,
Graham Nelson <gra...@gnelson.demon.co.uk> wrote:
>> That's also, by the way, much the way the VAB was intended to operate.
>> The original notion was that only the most basic final procedures would
>
>Why do any work at the pad at all, other than final fuelling?
>Doesn't it just increase the nuisance factor, increase the time
>when the rocket is open to the weather and force you to load the
>payload vertically rather than horizontally?
Well, basically, yes. Given that you've got infrastructure like the VAB,
it would make a whole lot of sense to roll the bird out to the pad only
when you're actually ready to launch. There are a few things that really
have to be done at the last minute, like adding the crew, the cryo fuels,
and any experimental animals, but that should be it.
One source of complications in this is the Cape safety fascists. For
example, do you install pyro devices -- e.g., the detonators for the
hold-downs -- in the VAB? The shuttle was designed to do things that way,
with the consent of the safety people, but they then had second thoughts,
and it has never been allowed in practice -- pyros must be installed on
the pad. (Kourou lets you install pyros earlier, and I think most of the
other non-US launch sites do too, but that means nothing at the Cape.)
The biggest obstacle, though, is just tradition. NASA is used to doing
lots of fiddling on the pad; all their standard practices are built around
that assumption. The Air Force people farther south on the Cape are no
different. Changing this to a system where the bird never sits overnight
on the pad unless it's launching first thing in the morning would require
either compelling need or determined management, and neither is present.
Jens A. Lerch
"Michael Morton" <m...@sys.tuna> wrote:
>Graham Nelson <gra...@gnelson.demon.co.uk> wrote:
>> Why do any work at the pad at all, other than final fuelling?
>> Doesn't it just increase the nuisance factor, increase the time
>> when the rocket is open to the weather and force you to load the
>> payload vertically rather than horizontally?
>It's interesting that ESA has gone over to the 'bare pad' idea
>for Ariane 5, unlike Ariane 4 which had payload integration on
>the pad. I'm guessing, but I suppose that would have been
>excessively combersome when the A5 was manifested for 3 payloads.
The payload of Ariane 4s is integrated into the fairing in the
controled enviroment of a special payload integration facility. The
entire fairing is placed on top of the launcher on the pad. Very
little work is done on the pad.
/\ Jens A. Lerch
|| jle...@geocities.com
|| My Astronautics page has moved to
/||\ http://www.geocities.com/CapeCanaveral/2221
Kelly McDonald
>>"minor" in comparison to a stretch of the VAB, perhaps?
>>(Henry? how much of a stretch did you envision, and how much headroom
>>was there in the VAB?)
I believe that the largest vehicle that the VAB could support was 410
feet. The maximum overhead crane height. So there should have been
quite a bit of room left for stretches. Some studies planned for up to
a 498 inch stretch on the first stage.
Kelly McDonald
Tim Johnson
Henry Spencer wrote:
>
> In article <ant272040868M+4%@gnelson.demon.co.uk>,
> Graham Nelson <gra...@gnelson.demon.co.uk> wrote:
> >> That's also, by the way, much the way the VAB was intended to operate.
> >> The original notion was that only the most basic final procedures would
> >> be done on the pad...
> >
> One source of complications in this is the Cape safety fascists. For
> example, do you install pyro devices -- e.g., the detonators for the
> hold-downs -- in the VAB? The shuttle was designed to do things that way,
> with the consent of the safety people, but they then had second thoughts,
> and it has never been allowed in practice -- pyros must be installed on
> the pad. (Kourou lets you install pyros earlier, and I think most of the
> other non-US launch sites do too, but that means nothing at the Cape.)
When I worked at KSC during the mid-1980s, I was amazed to discover how
much
wasted space existed in the VAB. The building once housed four vertical
assembly bays (only three were ever fully used, and only two are used
now).
Between the bays are what amount to several 400-foot tall office
towers.
During the days of Project Apollo, these were filled with the offices of
stage contractors. Boeing used the lower floors, nearest their Saturn V
first stage, then came North American and Douglas. When Shuttle
arrived,
these offices could no longer be used. Saturn V had been inert when in
the VAB. STS, with its big solid rockets, is not. As a result, the
taxpayers had to ante up for a whole new set of office buildings outside
the VAB for Rockwell, etc.
I enjoyed wandering the halls of the abandoned VAB offices. There were
still newspapers, etc, from the 1970s scattered about...
Tim Johnson
ti...@interaccess.com
bothered
me was the way
Damon Hill
>When I worked at KSC during the mid-1980s, I was amazed to discover how
>much
>wasted space existed in the VAB. The building once housed four vertical
>assembly bays (only three were ever fully used, and only two are used
>now).
>Between the bays are what amount to several 400-foot tall office
>towers.
>During the days of Project Apollo, these were filled with the offices of
>stage contractors. Boeing used the lower floors, nearest their Saturn V
>first stage, then came North American and Douglas. When Shuttle
>arrived,
>these offices could no longer be used. Saturn V had been inert when in
>the VAB. STS, with its big solid rockets, is not. As a result, the
>taxpayers had to ante up for a whole new set of office buildings outside
>the VAB for Rockwell, etc.
>
>I enjoyed wandering the halls of the abandoned VAB offices. There were
>still newspapers, etc, from the 1970s scattered about...
My ever-annoying bother-in-law works at the Cape and makes frequent
trips into the VAB. He says some of those offices are used to store
old odds and ends; while assisting him on a project last December, he
had to run over there to rummage for some equipment rack parts. No
budget for new stuff, or very little, so he had to make do with what he
could scrounge. It's an art, you know.
Then there are the buzzards, wild pigs, alligators and other fauna
he has to occasionally contend with too. The whole location is at
times a bit surreal.
--Damon