The primary feature of the memorial is the Space Mirror, a large mirror of black granite, divided into 90 smaller panels. The names of the 24 astronauts who have died are scattered over the mirror, with names of astronauts who died in the same incident grouped on the same panel, or pairs of adjacent panels. The names are cut completely through the surface, exposing a translucent backing, and filled with translucent acrylic, which is then backlit with a combination of reflected sunlight (when available) and floodlights, causing the names to glow, and appear to float in a reflection of the sky.

Theodore Freeman, one of the "Astronaut Group 3" recruits from 1963, died in a T-38 training accident on October 31, 1964.

Elliot See and Charles Bassett were killed in a T-38 accident on February 28, 1966 when their aircraft crashed into McDonnell Building 101 on a foggy day. They were originally slated to be the crew of Gemini 9. Bassett was another Group 3 recruit, whereas See was an Astronaut Group 2 recruit from 1962.

Virgil Grissom, Edward White and Roger Chaffee were in the Apollo 1 capsule for plugs-out test on January 27, 1967 when a short circuit ignited flammable materials in the pressurized pure-oxygen atmosphere. The astronauts died of carbon monoxide poisoning before ground crews could reach them. Grissom, one of the "Mercury Seven" astronauts, had flown twice before. White conducted the first US spacewalk on Gemini 4. Chaffee, a rookie, was a Group 3 recruit.

Clifton "C.C." Williams died in a T-38 training crash on October 5, 1967. Another Group 3 recruit, he was in the Apollo astronaut rotation, and would have been on the crew of Apollo 12. He was also memorialized by a fourth star on the official Apollo 12 mission badge.

Michael J. Adams died in an X-15 crash on November 15, 1967. He was not a NASA astronaut recruit, but made the memorial by virtue of having earned the Astronaut Badge according to the USAF standard by reaching just over 50 miles in altitude on his fatal flight. He was also in the United States Air Force's Manned Orbiting Laboratory program.

Robert H. Lawrence, Jr. died on December 8, 1967, when the F-104 he was testing crashed and his ejection seat parachute failed to open. He was in the Manned Orbiting Laboratory program at the time, and could have become among the first African-American astronauts had he survived to take NASA's offer for all under-35 MOL candidates to join their space program when MOL was scrapped in 1969.

On January 28, 1986, the Space Shuttle Challenger broke apart 73 seconds after liftoff on mission STS-51-L. All seven crew members — Francis "Dick" Scobee, Michael J. Smith, Ronald McNair, Gregory Jarvis, Judith Resnik, Ellison Onizuka, and Christa McAuliffe — died. Scobee, McNair, Resnik and Onizuka had flown before. McAuliffe was participating via the Teacher in Space Project.

M. L. "Sonny" Carter died on April 5, 1991, in the crash of Atlantic Southeast Airlines Flight 2311. Carter was a passenger traveling on NASA business. He had flown on STS-33 and was in training for STS-42 at the time.

On February 1, 2003, the Space Shuttle Columbia disintegrated on re-entry at the end of mission STS-107 due to damage during ascent. The crew was Rick D. Husband, William C. McCool, David M. Brown, Kalpana Chawla, Michael P. Anderson, Laurel Clark and Ilan Ramon. Husband, Chawla and Anderson were veterans. Ilan Ramon was a pilot in the Israeli Air Force.