Altair

Mission Profile

Altair (Lunar Surface Access Module, LSAM) was NASA's proposed crewed lunar lander for the Constellation program, designed to carry four astronauts from lunar orbit to the surface and return two of them to the orbiting Orion spacecraft. Powered by hypergolic main descent engines and a cryogenic oxygen/methane ascent engine, Altair was designed for both sortie missions to any lunar location and crew rotation missions to a permanent lunar outpost near the south pole. Launched separately from the Orion crew vehicle atop an Ares V cargo rocket, it would have enabled surface stays of up to seven days for sortie missions. Altair's development was cancelled in 2010 when the Constellation program was terminated, though its design influenced subsequent lunar lander concepts including NASA's Human Landing System.