Buzz Aldrin on July 20, Aldrin and Armstrong entered "Eagle", and began the final preparations for lunar descent. At 17:44:00 "Eagle" separated from the "Columbia". Collins, alone aboard "Columbia", inspected "Eagle" as it pirouetted before him to ensure the craft was not damaged, and that the landing gear was correctly deployed. Throughout the descent, Aldrin called out navigation data to Armstrong, who was busy piloting the "Eagle". Five minutes into the descent burn, and above the surface of the Moon, the LM guidance computer (LGC) distracted the crew with the first of several unexpected alarms that indicated that it could not complete
Neutral buoyancy simulation as a training aid post-mission evaluation of problems that he encountered during his Gemini IX-A EVA. NASA then modified the contract to include pre-mission training of Gemini XII astronaut, Buzz Aldrin. Astronaut Cernan also participated in this pre-mission training, as he was in a backup role to Aldrin as pilot of Gemini XII. Aldrin trained for the original Gemini XII EVA version which was then revised to eliminate the task of using a manned maneuvering unit. Aldrin returned to the McDonogh facility and trained for the final version of his EVA. NASA considered the flight EVA to be a total success, and Aldrin again