Critical Design Review of the Apollo CM Block II Program: Apollo. Spacecraft: Apollo CSM.
Part I of the Critical Design Review of the crew compartment and the docking system in the Block II CM was held at North American. Systems Engineering (SED) and Structures and Mechanics (SMD) divisions, respectively, evaluated the two areas.
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- Crew compartment:
- The restraint harness, acceptable in the Block I vehicle, interfered with attachments for the suit umbilicals. These attachments were critical for suit ventilation and mobility; the harness location was likewise critical for crew impact tolerances. Evaluation of alternate locations for the harness and umbilical fittings - or both - awaited the availability of a couch mockup. Manned sled tests might be needed to verify any harness changes.
- Restraints at the sleep station must be redesigned. At present, they did not allow sufficient room for a crewman in his pressure suit.
- To save weight, North American planned to strap crew equipment to shelves and bulkheads (rather than stowing such gear in compartments, as was done on the Block I vehicle).
- Most serious, in an earth landing, when the attenuator struts compressed, the couches would strike a portable life support system (PLSS). "No analysis has been made," SED reported, "to show that this is acceptable." For in such an occurrence, the crew could be injured or killed, the oxygen tank in the PLSS (under about 409 kg (900 lbs) of pressure) could explode, and the aft bulkhead might be ruptured. North American was scheduled to report on this problem on April 27.
- Docking system:
- SMD approved the probe and drogue concept, but recommended that fittings be standardized throughout (so that only one tool was needed).
- The division also approved North American's design for the outer side hatch (i.e., limiting its deployment to 90 degrees), pending MSC's final word on deployment requirements.
- The division recommended that the forward hatch mechanism be simplified. (North American warned of schedule delays.)