September 21, 2004

wrote:

Put a capsule on the Delta IV Medium, and lunar circumnavigation is
possible, using the upper stage as your service module. In LEO, you
could retrofit the upper stage into space station modules. You get
three Delta IV Mediums for the price of a single heavy.


Only if your service module, and all of the life support and
guidance propulsion requirements, have a mass that is less
than 4 metric tons for Delta IV-M or no more than about
6 metric tons for Delta IV-M+(5,4).

My group is not interested in SRB propulsion, so we are focusing on a 3
ton limit for manned lunar circumnavigation.

The Apollo Command Module mass was about 6 metric tons, but
its 24.5 metric ton Service Module carried 1.2 metric tons
of equipment and fuel to produce electricity, water, and
oxygen. It also carried a ton or more of RCS fuel and
hardware needed to keep the vehicle under control. The
latter masses would have to be added to the Delta IV second
stage, which would directly reduce payload capability.

As I stated, we are focusing on a manned lunar circumnavigation for the
purposes of space advocacy and IMAX and film production, solar power and
hydrogen energy conversion technology promotion, hydrogen propulsion
promotion, and of course, Boeing Delta IV Medium promotion. The mass
fractions are tight for this mission, but should be doable with modern
design criteria, techniques and equipment. To us, it makes very little
sense to actually orbit and land on the moon at this point in the
process.

For LEO it's a bit better, because you get the hydrogen tank for habitat
retrofit, and the oxygen tank for ... oxygen. Here it goal is retrofit
demonstration, and in addition to the above, hydrogen powered SSTO
advocacy and promotion.

CELSS comes later, but we are working with that on the ground.

Thomas Lee Elifritz
http://elifritz.members.atlantic.net