[it] will likely consist of a pressurized section, an unpressurized equipment section, and an experiments module. The pressurized module should include an operating compartment with about 500 cubic feet [of] volume, and a separate living-working compartment large enough to accommodate needs for 30 days' flight, probably some 500 to 700 feet ... Payload capacity should be as large as possible. Estimates of a meaningful test program have included about 3,000 to 5,000 pounds of discretionary test equipment ... [The personnel module] will operate in a quiescent mode for the on-orbit duration, and then have the ability to loiter, manned, for about 12 hours, re-enter safely for water recovery ...