Re: Shift from LEO-Assembly to Single-Vehicle Strategy for Lunar Mission

In article <pu06649db4rn6qs3bscf1vu6qd5rn36tp4@xxxxxxx>,
seagull@xxxxxxxxxxxxxxx wrote:

On Fri, 11 Apr 2008 10:02:40 -0700 (PDT), are <Proponent@xxxxxxx>
wrote:

I had long thought before Apollo it was widely agreed that the way to
get to the moon was through assembly or at least re-fueling in low
Earth orbit, and that it was Apollo's end-of-the-decade deadline that
resulted in the use of a single large launch vehicle (or, in EOR mode,
two large vehicles). For example, as late as 1959, the Army's Project
Horizon proposed the use of half a dozen Saturn IB-class launch
vehicles, with assembly or re-fueling.

Actually, though, the single-vehicle approach seems to have been
rising even before JFK imposed the 1970 deadline. NASA's long-range
plan of 1960 envisioned a manned lunar landing only after the
development of the Nova, which would have been in the Saturn V class.
The Air Force's Project Lunex, initiated in 1958 and completed in
1961, also went for a single large launch vehicle.

So, why the seeming shift in approach, even before the JFK deadline?
Did the fact that ICBM-sized rockets (e.g., Atlas and Titan) had come
on line by 1960 make engineers less conservative about large vehicles?
Did early space-operations experience make them more conservative
about complex orbital operations? Was there a political imperative to
make use of the F-1 engine? Was NASA, before it absorbed the von Braun
team in late 1960, trying to justify a large booster effort
independent of the Army's Saturn?

A related question; it's interesting that Lunex, despite being the Air
Force's baby, would not have utilized the F-1. So just what was the
Air Force thinking when it began the F-1 project in the mid-1950s? Did
it ever have a particular application in mind?

I would like to know the reason for the change in approach also, sorry
I don't have the answer. Unfortunately the other two posters are using
unreliable translation programs and had reply's that had nothing to do
with your questions.
JBL

The development of the F-1 and J-2 engines allowed a significantly
larger booster rocket assembly than those previously envisioned.

The Sat-V was actually a Nova, but was called a Saturn, to please the
budgeteers, implying that it was just an extension of the Saturn-I
series developed at MSFC. The Sat-I and Sat-IB were puny (2-stages, 1.5M
lbf thrust), compared to the Sat-V (7.5M lbf thrust, 3 stages).

Both Sat-IB and Sat-V had the S-IVB upper stage, but LOX/H2 Sat-V had
the LOX/H2 S-II second stage (1M lbf thrust), allowing a very heavy lift
capability.

Having the entire mission contained in one booster/spacecraft/lander
combo eliminated the uncertainties of multiple launches and rendezvous
in Earth orbit.

--
Remove _'s from email address to talk to me.
.

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