From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Saturn history
Date: Tue, 15 Dec 1992 20:28:21 GMT
Organization: U of Toronto Zoology

In article <12DEC199216245144@judy.uh.edu> wingo%cspara.decnet@Fedex.Msfc.Nasa.Gov writes:
>>     Centaur on the Saturn? I think I remember that it was considered
>>     as a fourth stage for Saturn 5 (with early Voyager planning?) but
>>     I believe you're confusing the RL-10 and the Centaur. RL-10
>>     powered the S-IV (predecessor to the J-2 powered S-IVB)...
>
>The Saturn I/Centaur configuration is the original Saturn I multistage vehicle.
>I confirmed this when re-reading General Medaris's book. He specifically
>names the Centaur as the Saturn I upper stage.

Methinks Medaris is confused, or is giving a some early design study
too much weight.  (It would not be unprecedented; Michael Collins, in one
of his books, described an important aspect of the Apollo LM wrong.)

The original Saturn I development effort had no upper stage at all.
Many, many different configurations were studied -- literally dozens --
with particular emphasis on putting an entire Titan or Atlas on top
to minimize development effort.  The confusion about upper-stage choice
lasted long enough to be a serious obstacle to progress.  Stages To Saturn
contains considerable detail on this.

As far as I know, none of those configurations used a Centaur as a
second stage.  It was too small to exploit the first stage properly.
It did show up as a third stage on Saturn-Atlas and Saturn-Titan concepts.

The Saturn I, as built, had two stages, the second being (as Brian noted)
the S-IV.  This was an oddball, never used for anything else.  It was sort
of Centaur's big brother, with six RL10s instead of Centaur's two, but was
not a Centaur derivative in any significant way.  Saturn I never flew with
any other upper stage(s).

>The Centaur was considered as the upper stage (4th) for the Saturn V...
>to support the Grand Tour by the original Voyagers. This little beastie had
>the Nerva as the Third stage with the Centaur as the 4th! Man Talk about 
>Delta V or lift capability! I saw this scenario carefully laid out in one of
>the Marshall books on what was called the "Apollo Applications Program". This
>little configuration could lift two Voyager class full up ground tours...

Okay, now here we do have serious confusion.  The original Voyager had
nothing at all to do with the Grand Tour mission.  The first program named
Voyager was Viking's big brother, aiming to send large unmanned orbiters
and landers to Mars in the 1970s.  (Its objectives had originally included
Venus too, before it became clear just how unappetizing a place Venus is.)
It died completely in late-1960s cutbacks, as did the Grand Tour project
a bit later.  The name was re-used for a project originally dubbed
Mariner Jupiter-Saturn, a drastically shrunken reincarnation of Grand Tour
that managed to add Uranus and Neptune on the end as secondary objectives.

Voyager's original launch vehicle was the Saturn IB/Centaur, which was
never built.  It got hit by a double whammy in the mid-1960s:  first,
better data on Mars's atmosphere showed it was much thinner than formerly
thought, which meant major weight growth in Voyager's heatshield/parachute
system, driving Voyager beyond Saturn IB/Centaur's lift limit; and second,
NASA had its first budget squeeze, wanted to reduce the number of launch
vehicles it was involved in, and saw that Voyager was Saturn IB/Centaur's
only customer.

Voyager ended up planned for launch two at a time on a standard Saturn V,
which contributed to its demise by running up its costs.  (The Pasadena
Party Line blames NASA HQ for the launcher switch, but it's hard to see
what else could have been done after the weight growth, especially given
a desire not to get involved in yet more new launcher configurations.)
There wasn't any need for further stages or nuclear stages; the Saturn V
as it stood was really over-large for Voyager.

I haven't been able to find any detail on what launcher was planned for
the original Grand Tour project.  Note, though, that it was not part
of Apollo Applications, which was entirely a manned program.
-- 
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  henry@zoo.toronto.edu  utzoo!henry