SAE 2009-01-2477 : 2009

NASA is working to develop a new lunar lander to support lunar exploration. The development process that the Altair project is using for this vehicle is unlike most others. In “Lander Design Analysis Cycle 1” (LDAC-1), a single-string, minimum functionality design concept was developed, including life support systems for different vehicle configuration concepts. The first configuration included an ascent vehicle and a habitat with integral airlocks. The second concept analyzed was a combined ascent vehicle-habitat with a detachable airlock. In LDAC-2, the Altair team took the ascent vehicle-habitat with detachable airlock and analyzed the design for the components that were the largest contributors to the risk of loss of crew (LOC). For life support, the largest drivers were related to oxygen supply and carbon dioxide control. Integrated abort options were developed at the vehicle level. Many life support failures were not considered to result in LOC because the effects take long enough to develop that the mission can be ended safely before the situation becomes life threatening. These failures were then classified as LOM failures. Many different options to reduce each LOC risk were considered, and mass efficient solutions to the LOC problems were added to the vehicle design at the end of LDAC-2. In LDAC-3, the new design was analyzed for large contributors to the risk of LOM. To avoid ending the mission early or being unable to accomplish primary objectives like performing all planned extravehicular activities (EVAs), various options were assessed for risk reduction achieved and mass and power cost. This paper outlines the major assumptions, design features, and decisions related to the development of the life support system for the Altair project through LDAC-3.

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