Armstrong cut his teeth flying jets for the Navy before joining NASA, seeing action over Korea in 1951 and 1952. He was assigned to VF-51 onboard the USS Essex, where he flew the F9F-2 Panther. Pictured: F9F-2 Panthers taking off from the Essex sometime in 1951. Credit: U.S. Navy.

After leaving the Navy, Armstrong became a test pilot for NASA's X-15 program, a high-speed, high-altitude rocket plane. He flew a total of seven flights, reaching an altitude of nearly 63 km and a speed of well over 6,000 km/h. Here, he poses with his aircraft on New Year's Day, 1960.

Astronauts during tropical survival training at Albrook Air Force Base in Panama, 1963. Left to right: Unidentified trainer, Armstrong, John Glenn, Gordon Cooper, and Charles "Pete" Conrad.

Armstrong suiting up for his Gemini 8 flight with Dave Scott, March 3, 1966.

Armstrong (foreground) and Dave Scott prepare to enter their Gemini 8 capsule.

Armstrong during Gemini 8 pre-launch countdown.

Gemini 8's mission was to rendezvous and dock with an Agena satellite, proving the feasibility of the techniques for future moon flights. Pictured: The Agena satellite.

The prime and backup crews of Gemini 11 at the Gemini Mission Simulator at Cape Kennedy. Left to right: William A. Anders, Richard F. Gordon, Charles "Pete" Conrad, and Armstrong.

Portrait of Apollo 11 crew. Left to right: Lunar module pilot Buzz Aldrin, commander Armstrong, and command module pilot Michael Collins.

Armstrong strums on a ukelele in the Mobile Quarantine Facility several months before the Apollo 11 mission.

Liftoff of Apollo 11 on July 16, 1969.

The Apollo 11 lunar module Eagle beginning its descent to the surface of the moon.

Earthrise in lunar orbit, July 20, 1969. This phenomenon is not generally visible on the moon's surface.

Aldrin poses with the American flag.

Buzz Aldrin on the surface of the moon -- Armstrong is visible in the reflection on Aldrin's visor.

Armstrong on the surface of the moon.

Armstrong after returning to the lunar module.

President Nixon greets the Apollo 11 astronauts while still in quaratine, July 24, 1969.

The Apollo 11 astronauts enjoy a tickertape parade in New York City, August 13, 1969.

Armstrong's space suit during the Apollo 11 mission.

Armstrong at Apollo 11 twentieth anniversary picnic, 1989. Credit: Johnson Space Center.