NASA Astronaut Group 3 experience was substituted. This applied to Aldrin, Anders, Cernan, Chaffee, Cunningham and Schweickart; all the others were test pilots. NASA Astronaut Group 3 Astronaut Group 3 was a group of fourteen astronauts selected by NASA. Their selection was announced in October 1963. Four died in training accidents before they could fly in space. All of the surviving ten flew in the Apollo program; five also flew Gemini missions. Aldrin, Bean, Cernan and Scott walked on the Moon. They are the only ones of the first 19 NASA astronaut groups to have no members at all fly on the Space Shuttle.
Space rendezvous maneuvering thrusters to adjust its orbit to match that of its twin. The initial separation distances were in the range of , and slowly diverged to thousands of kilometers (over a thousand miles) over the course of the missions. In 1963 Buzz Aldrin submitted his doctoral thesis titled, " Line-Of-Sight Guidance Techniques For Manned Orbital Rendezvous." As a NASA astronaut, Aldrin worked to "translate complex orbital mechanics into relatively simple flight plans for my colleagues." The first attempt at rendezvous was made on June 3, 1965, when US astronaut Jim McDivitt tried to maneuver his Gemini 4 craft to meet