In article ,
Derek Lyons wrote:
That's where the modular concept for Apollo came from...

The problem with this statement is... There is nothing modular about
the Apollo spacecraft. The CSM is a matched pair always and forever.

Uh, no, not really. The CM needs *some sort* of SM, but it doesn't have
to be the lunar-mission SM. Many of the proto-Skylab concept drawings,
for example, show Apollos with what are clearly *not* lunar SMs. The SM
provided a few well-defined services via well-defined interfaces, and
doing alternate versions wouldn't have been a big trick. A station ferry,
for example, could have a much smaller main engine with much smaller
tanks, no high-gain antenna, batteries instead of fuel cells, and
compressed GOX rather than LOX for breathing.

In fact, it would have made sense to build a revised SM even for later
lunar missions, with a smaller but more sophisticated main engine, giving
lower thrust but higher Isp. The SPS was sized for a lunar takeoff, to
get development going before the EOR/LOR war was over.

Somewhat odder are the "mission modules" that some early concepts showed.
Some just had instruments operated from the CM, but others seemed to be
manned, with pressurized internal volume... but it wasn't clear how you
would *get there* from the CM.

In hindsight, Apollo would have been more versatile if built like the TKS,
with a heatshield hatch and a pressurized SM.

The impression that Owen gave me was basically that these three files
(space station, Lunar mission and Mars mission) were developed to
similar levels by the engineering team, and used as lures by Gilruth
et al. to tempt Kennedy's administration into agreeing to some sort of
post-Mercury program.

So how does all this square with the known fact that the STG and NASA
senior management were caught utterly blindsided by Kennedy's
announcement of the lunar mission?

They weren't envisioning anything like that *schedule*. Their idea of a
lunar-mission focus was LEO flights in the mid-60s, and high-orbit and
then circumlunar flights in the late 60s, followed by development of
second-generation hardware to attempt a lunar landing in the mid-late 70s.
The original specs for what became the CSM called for missions in Earth
orbit and lunar orbit... but not a landing.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |