Apollo 1, initially designated AS-204, was planned to be the first crewed mission of the Apollo program, the American undertaking to land the first man on the Moon. It was planned to launch on February 21, 1967, as the first low Earth orbital test of the Apollo command and service module. The mission never flew; a cabin fire during a launch rehearsal test at Cape Kennedy Air Force Station Launch Complex 34 on January 27 killed all three crew members—Command Pilot Gus Grissom, Senior Pilot Ed White, and Pilot Roger B. Chaffee—and destroyed the command module (CM). The name Apollo 1, chosen by the crew, was made official by NASA in their honor after the fire.
Immediately after the fire, NASA convened an Accident Review Board to determine the cause of the fire, and both chambers of the United States Congress conducted their own committee inquiries to oversee NASA's investigation. The ignition source of the fire was determined to be electrical, and the fire spread rapidly due to combustible nylon material and the high-pressure pure oxygen cabin atmosphere. Rescue was prevented by the plug door hatch, which could not be opened against the internal pressure of the cabin. Because the rocket was unfueled, the test had not been considered hazardous, and emergency preparedness for it was poor.

During the Congressional investigation, Senator Walter Mondale publicly revealed a NASA internal document citing problems with prime Apollo contractor North American Aviation, which became known as the Phillips Report. This disclosure embarrassed NASA Administrator James E. Webb, who was unaware of the document's existence, and attracted controversy to the Apollo program. Despite congressional displeasure at NASA's lack of openness, both congressional committees ruled that the issues raised in the report had no bearing on the accident.

Crewed Apollo flights were suspended for twenty months while the command module's hazards were addressed. However, the development and uncrewed testing of the lunar module (LM) and Saturn V rocket continued. The Saturn IB launch vehicle for Apollo1, SA-204, was used for the first LM test flight, Apollo 5. The first successful crewed Apollo mission was flown by Apollo1's backup crew on Apollo 7 in October 1968.

Crew
First backup crew (April–December 1966)
Second backup crew (December 1966 – January 1967)
Apollo crewed test flight plans
AS-204 was to be the first crewed test flight of the Apollo command and service module (CSM) to Earth orbit, launched on a Saturn IB rocket. AS-204 was to test launch operations, ground tracking and control facilities and the performance of the Apollo-Saturn launch assembly and would have lasted up to two weeks, depending on how the spacecraft performed.
The CSM for this flight, number 012 built by North American Aviation (NAA), was a Block I version designed before the lunar orbit rendezvous landing strategy was chosen; therefore it lacked the capability of docking with the lunar module. This was incorporated into the Block II CSM design, along with lessons learned in Block I. Block II would be test-flown with the LM when the latter was ready.
Director of Flight Crew Operations Deke Slayton selected the first Apollo crew in January 1966, with Grissom as Command Pilot, White as Senior Pilot, and rookie Donn F. Eisele as Pilot. But Eisele dislocated his shoulder twice aboard the KC-135 weightlessness training aircraft, and had to undergo surgery on January 27. Slayton replaced him with Chaffee, and NASA announced the crew selection on March 21, 1966. James McDivitt, David Scott and Russell Schweickart were named as the backup crew.
On September 29, Walter Schirra, Eisele, and Walter Cunningham were named as the prime crew for a second Block I CSM flight, AS-205. NASA planned to follow this with an uncrewed test flight of the LM (AS-206), then the third crewed mission would be a dual flight designated AS-278 (or AS-207/208), in which AS-207 would launch the first crewed Block II CSM, which would then rendezvous and dock with the LM launched uncrewed on AS-208.
In March, NASA was studying the possibility of flying the first Apollo mission as a joint space rendezvous with the final Project Gemini mission, Gemini 12 in November 1966. But by May, delays in making Apollo ready for flight just by itself, and the extra time needed to incorporate compatibility with the Gemini, made that impractical. This became moot when slippage in readiness of the AS-204 spacecraft caused the last-quarter 1966 target date to be missed, and the mission was rescheduled for February 21, 1967.





