Concept drawing of Altair (NASA)
UPDATE: 11 October 2010. In a major policy speech, Barack Obama formally ended the Constellation Program. He instructed NASA to begin work on a rocket for deep space exploration. He also directed that commercially based means be used to launch ISS crew members.
Altair is the brightest star in the Aquila constellation and the twelfth brightest star in the nighttime sky. For the sci-fi buff, Altair IV was the planet featured in the film Forbidden Planet.
The lunar surface access module was to consist of a descent stage and an ascent stage. It wwould carry a crew of four, leaving the Orion crew exploration vehicle in unmanned lunar orbit.
The latest concept drawing shown above differs from earlier concept drawings, shown below.