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
Buzz Aldrin (CMP) and Aldrin as Lunar Module Pilot (LMP). Their assignment as the backup crew of Apollo 9 was officially announced on November 20, 1967. Due to design and manufacturing delays in the lunar module (LM), Apollo 8 and Apollo 9 swapped prime and backup crews, and Armstrong's crew became the backup for Apollo 8. Under the normal crew rotation scheme, Armstrong was then expected to command Apollo 11. Michael Collins, the CMP on the Apollo 8 prime crew, experienced trouble with his legs that doctors diagnosed as a requiring surgery. Lovell took his place on the Apollo 8 crew. When