Morehead Planetarium and Science Center Armstrong. Armstrong visited again only months before the 1969 launch of Apollo 11, spending a total of 20 days at Morehead over 11 training sessions, more than any other astronaut. Astronauts commented that the "large dome" was "highly realistic", calling the facility "superb". In all, the astronauts who trained at the planetarium were Buzz Aldrin, Joseph P. Allen, William Anders, Neil Armstrong, Charles Bassett, Alan Bean, Frank Borman, Vance D. Brand, John S. Bull, Scott Carpenter, Gerald P. Carr, Eugene Cernan, Roger B. Chaffee, Philip K. Chapman, Michael Collins, Pete Conrad, Gordon Cooper, Walter Cunningham, Charles Duke, Donn F. Eisele,
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