Apollo 1

Apollo 1 (initially designated Apollo Saturn-204 and AS-204) was scheduled to be the first manned mission of the U.S. Apollo manned lunar landing program, with a target launch date of February 21, 1967. A cabin fire during a launch pad test on January 27 at Launch Pad 34 at Cape Canaveral killed all three crew members—Command Pilot Virgil "Gus" Grissom, Senior Pilot Edward H. White and Pilot Roger B. Chaffee—and destroyed the Command Module. The name Apollo 1, chosen by the crew, was officially retired by NASA in commemoration of them on April 24, 1967.

Immediately after the fire, NASA convened the Apollo 204 Accident Review Board to determine the cause of the fire. Although the ignition source was never conclusively identified, the astronauts' deaths were attributed to a wide range of lethal design and construction flaws in the early Apollo Command Module. The manned phase of the project was delayed for 20 months while these problems were corrected.

The Saturn IB launch vehicle, SA-204, scheduled for use on this mission, was later used for the first unmanned Lunar Module test flight, Apollo 5. The first successful manned Apollo mission was flown by Apollo 1's backup crew on Apollo 7 in October 1968.