Apollo CSM

In 1967 it was planned that Saturn IB-launched Orbital Workshops would be supplied by Apollo CSM spacecraft and Resupply Modules (RM) with up to three metric tons of supplies and instruments.

Following launch by a Saturn IB, the Apollo would back away, transpose, and dock with the RM, just as with the Lunar Module for the lunar missions. These modules could be left docked to the Workshop docking module. Later the Orbital Workshop became Skylab, launched by a Saturn V, and the RM's were not needed. However a descendent of the RM flew in the form of the Apollo-Soyuz Test Project Docking Module.

An even earlier iteration of the concept was in 1963. In 1962 NASA funded studies with several contractors on Operations and Logistics for Space Stations. North American's study was dated 18 March 1963 and proposed two alternatives, the first of which was an 'Apollo-I' derivative of Apollo, with a cargo resupply module.

Crew Size: 3. Orbital Storage: 90 days. Maximum Diameter: 3.90 m (12.70 ft). Habitable Volume: 6.20 m3. Mass: 18,600 kg (41,000 lb). Payload: 3,000 kg (6,600 lb). RCS Impulse: 3,530 kgf-sec. Main Engine: AJ10-137. Main Engine Thrust: 97.860 kN (22,000 lbf). Main Engine Propellants: N2O4/UDMH. Main Engine Propellants: 1,200 kg (2,600 lb). Main Engine Isp: 314 sec. Spacecraft delta v: 200 m/s (650 ft/sec). Electrical System: Fuel cells. Electric System: 6.30 average kW. Electric System: 670.00 kWh. Associated Launch Vehicle: Saturn IB.

• Big G, Briefing, McDonnell Douglas, 20 December 1967. Thanks to Mike Macowski for discovering and providing this material.