On board Apollo 1 were astronaut Virgil I. "Gus" Grissom, (the second American astronaut to fly into space) astronaut Edward H. White II, (the first American astronaut to "walk" in space) and astronaut Roger B. Chaffee, (a "rookie" astronaut on his first space mission).
At 1:00 PM the Apollo 1 crew entered the capsule. They had several problems throughout the afternoon, which caused a lot of delays. At 6:31 PM, a voice was heard on the communications link yell, Fire, I smell fire.
The fire spread quickly through the cabin because the oxygen level was so high, and oxygen burns rapidly. Rescuers had trouble getting in to help because the hatch was held closed by several clamps which took a lot of work to open.
All three men died in the fire. The Apollo program was stopped until the experts could decide what had gone wrong during the Apollo 1 test. Once they did, the program started again. The Apollo/Saturn 204 mission was officially named "Apollo 1" in honor of Grissom, White, and Chaffee. The first launch (unmanned) in November 1967 was called Apollo 4 (no missions were ever designated Apollo 2 or 3). On July 20, 1969, Neil Armstrong, on Apollo 11, became the first person to step on the moon.

