Henry Vanderbilt wrote:


Another possibility: For longer missions, launch two four-man CEV's
with three aboard each, dock them to each other in orbit, then operate
them as a dual-redundant unit with a bit of extra elbow room.

Which eliminates the need to fly a six-man CEV with attendant new
larger-than-EELV-heavy booster every time you rotate Station crew.
(Might as well still be flying Shuttle; it'll end up costing about
as much per flight.)

Henry

Sounds easy, simple and efficient, but ignores some practicalities of
CEV design. IF you go with a standard capsule shape, that means the
docking mechanism is going to end up at the bow of the capsule, as
every 'docking' capsule so far launched has done. Have you heard of a
design that does not do a bow-forward docking? with the exception of a
winged shape like lockheed's that would clearly not be intebded for
lunar or other than LEO travel, I just don't see it.

Now you have two small capsules docked end-to-end, with heatshields on
either end. There's no reasonable way to dock to anything else that
allows personnel access, like a space station, a lunar orbiter, an L-1
station, or, most importantly for the near term, a lunar lander. You've
created a dead-end system, useful for transport of 4 or 8 personnel.
And not much else, unless you're willing to go to ISS-type gigantic
modular vehicle assembly.

Perhaps that's possible if you're willing to ignore the architecture of
the 'Constellation' program that's been put forward to this point, or
if you're willing to limit yourself to 4 people. I just don't see that
happening, and obviously now neither does Mike Griffen.

Tom