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From: dil@mace.cc.purdue.edu (Perry G Ramsey)
Newsgroups: sci.space.shuttle
Subject: Re: For All Mankind [was Re: center engine out]
Summary: You can look it up
Message-ID: <5653@mace.cc.purdue.edu>
Date: 29 Sep 90 19:42:51 GMT
References: <15953@wpi.WPI.EDU> <1096@tsdiag.ccur.com> <5633@mace.cc.purdue.edu> <1990Sep28.151756.3973@infonode.ingr.com>
Distribution: sci.
Organization: Department of Earth and Atmospheric Sciences
Lines: 59

In article <1990Sep28.151756.3973@infonode.ingr.com>, drudetb@infonode.ingr.com (Ted B. Drude) writes:
> In article <5633@mace.cc.purdue.edu> dil@mace.cc.purdue.edu (Perry G Ramsey) writes:
> >RP-1 is the booster fuel in the Delta and Atlas, which are still the
>                                            ^^^^^
> Ahem.  I beg to differ.  The Atlas DOES use LH2 for its booster fuel.
> In fact,  it was the use of hydrogen fuel that made it possible for the Atlas
> to have such high payload weights for its day (late 50's-early 60's).

GARBAGE!  Go look in any reference.  The Atlas is RP-1 and LOX. 
The Centaur upper stage used along with the Atlas now is LH2, but
the basic booster uses RP-1.


> >Hydrogen makes sense for upper stages, but using it to boost from
> >the ground is not so great.
> 
> Until Energia (which also uses hydrogen) the Soviets had used nothing
> but kerosene/LOX for fuel.  They've  had huge boosters,  but relatively
> small payloads for their size.

Because the structures are so heavy.  Besides, as I said before,
hydrogen does make sense in the upper stages, where weight is
at a great premium.  For the first stage, though, the volume of
fuel consumed tends to override the weight savings.  I had my
Saturn V flight manual (AS-507) out last night, and I don't remember
all the details, but the SII had a fuel tank 50% larger than the 
S-IC, even though its total impulse was about 1/3 that of the S-IC
(410 million pound force-seconds vs. 1440 )  Now, it's true that
if LH2 had been used for the booster stage, all that impulse
wouldn't have been necessary, due to the lower fuel weight, but the
added size of the tankage would have made the stage heavier,
and making a clear comparison takes a lot more time than I have.
Everything is a trade off.  For the upper stages, hydrogen is
the clear winner, but for the booster, it isn't so certain.


 
> BTW,  when NASA  started to put Mercury capsules on Atlases

[etc.... based on the incorrect assertion that the
Atlas was LH2]i

> [von Braun's] reply was "He ought to get a  medal just for sitting on it!"

Up to that time, there had been a lot of problems with Atlases blowing
up or otherwise not making it to orbit.  It doesn't change the fact
that it was an RP-1 fueled vehicle.


(was it Glenn?)

Yes, John Glenn was the first American to orbit the earth.
(You mean you know all about boosters, but you don't know
what every six year old space buff knows?  Interesting.)
-- 
Perry G. Ramsey           Department of Earth and Atmospheric Sciences
perryr@vm.cc.purdue.edu   Purdue University, W. Lafayette, IN USA
dil@mace.cc.purdue.edu    We've looked at clouds from ten sides now, 
			  And we REALLY don't know clouds, at all.