In article ,
Derek Lyons wrote:
There is nothing modular about
the Apollo spacecraft. The CSM is a matched pair always and forever.
Wasn't there some non-trivial thoughts about a light-weight mini-SM for
use with Earth-orbit missions like Skylab?

There was. But substituting a SM late in the game isn't the same as
designing a modular system.

And likewise, designing a modular system which ends up only existing in
one version isn't the same as designing a non-modular system. Note that
Owen Maynard, who Kieran was quoting, was there, and you weren't.

Hint: think of what the M stands for in CM, SM, LM.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |