Apollo 1 failed to leave the launch pad after a fire consumed the Command Module. The accident occurred on Jan. 27, 1967 and claimed the lives of Virgil Grissom, Roger Chaffee and Edward White, who were astronauts aboard Apollo 1. No Apollo mission actually exploded upon launch.
The Apollo 1 fire occurred on a pre-flight test for what was scheduled to be the first manned Apollo mission. Following this disaster, the next five Apollo missions were unmanned. Manned missions resumed on Oct. 11, 1968, when Apollo 7 was the first successful mission, orbiting the earth 163 times.
The next several missions were successful. Apollo 13 had an explosion during the mission, but the spacecraft eventually landed safely. Apollo 17, the last mission and the last time men landed on the moon, concluded on Dec. 19, 1972.