The three astronauts scheduled to make the first Apollo space flight were killed when a fire swept through the command module.
Astronauts Virgil Grissom, Edward White and Roger Chaffee were all killed. They were the first American astronauts to die in a spacecraft.
The exhaustive investigation of the fire and extensive reworking of the Apollo command modules postponed crewed launches until NASA officials cleared them for flight.
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In the spring of 1967, NASA's Associate Administrator for Manned Space Flight, Dr. George E. Mueller, announced that the mission originally scheduled for Grissom, White and Chaffee would be known as Apollo 1.
NASA honors the Apollo 1 astronauts, and all other fallen astronauts on January 28th, which is also the anniversary of the Challenger disaster.