On 12 Aug 2003 11:17:40 -0400, jeff findley
wrote:

The propulsion and power systems to get the racks to and from the
Space Station. Even if this requires only half the mass of the Apollo
SM (and I think that's a realistic ballpark figure), we're still
talking two or three times the mass of the CM alone. All in a capsule
only a couple of feet greater in diameter than Apollo.

You're being grossly mislead by a system designed for lunar travel.

No, I'm not. Apollo was not designed for lunar travel, it was designed
as NASA's all-purpose manned spacecraft to succeed Mercury. The moon
mission came later.

That said, I am grossly overestimating its mass. Empty, the SM weighed
about 20,000 lbs., far less than I had thought. And that's about twice
as much as is needed for the LEO mission.

Remember that one of OSP's requirements is for greater maneuverability
than Shuttle. That's going to drive prop requirements significantly
higher.

I have no objection to a large capsule used for crew and cargo
transport. It's the proposal that the crew (or cargo) AND the
service systems (propulsion, life support -- more than a few hours
worth -- and electrical power) can be all compressed into a 15-ft
diameter capsule that I have difficulty accepting. My argument is
that if we want to reuse the service systems in addition to the crew
cabin, then the capsule is less suited for it than a winged or
lifting-body shape.

Where did you get 15 feet?

Lifeboat mode, to be launched aboard Shuttle. Unless we decide on two
variants (driving up costs) were stuck with 15 feet max.

Brian