Buzz Aldrin while Command Module Pilot Michael Collins remained in lunar orbit. A Presbyterian elder, Aldrin became the first person to hold a religious ceremony on the Moon when he privately took communion. Upon leaving NASA in 1971, he became Commandant of the U.S. Air Force Test Pilot School. He retired from the Air Force in 1972, after 21 years of service. His autobiographies "Return to Earth," (1973) and "Magnificent Desolation" (2009), recount his struggles with clinical depression and alcoholism in the years after leaving NASA. He continued to advocate for space exploration, particularly a manned mission to Mars, and developed the
Buzz Aldrin classroom work, and soon decided to pursue a doctorate instead. In January 1963, he earned a Sc.D. degree in astronautics. His doctoral thesis was "Line-of-Sight Guidance Techniques for Manned Orbital Rendezvous", the dedication of which read, "In the hopes that this work may in some way contribute to their exploration of space, this is dedicated to the crew members of this country's present and future manned space programs. If only I could join them in their exciting endeavors!" Aldrin chose his doctoral thesis in the hope that it would help him be selected as an astronaut, although it meant foregoing