Twelve of those astronauts landed on the Moon and walked on its surface, and six of those drove a Lunar rover on the Moon. While three astronauts had flown to the Moon twice, none of them landed on the Moon more than once. The nine Apollo missions to the moon all occurred between December 1968 and December 1972.
Apart from those twenty-four people who visited the moon, no human being has ever left low Earth orbit. They have, therefore, been further from the Earth than anyone else. They are also the only people to have seen the far side of the Moon directly. The twelve who walked on the moon are the only people ever to have set foot on an astronomical object other than the Earth.
Apollo 1 Crew (L-R: Gus Grissom, Ed White, Roger Chaffee)
Although there were no in-flight fatalities in the Apollo program, three astronauts died in a training accident that was later called Apollo 1.
They were stuck in a capsule on the launch pad when a fire broke out. The 100 percent oxygen atmosphere and flammable materials were cited as factors worsening the wiring-short sparked fire, while the hatch design precluded any hope of a timely escape. Numerous redesigns were incorporated into the spacecraft before manned flights resumed.
Virgil "Gus" Grissom - rumors claim he would have been the first man on the Moon if he had not died[1]
Duke was the youngest, at age 36 (+6mo); Shepard was the oldest, at age 47 (+2mo).
James A. Lovell, Young, and Cernan are the only three astronauts to fly more than one lunar mission (two each). Of these three, only Lovell did not walk on the lunar surface. Lovell and Fred Haise were prevented from walking on the Moon by the malfunction on Apollo 13 that resulted in the mission being aborted.
Joe Engle had also trained to explore the Moon with Eugene Cernan as the backup crew for Apollo 14, but Engle was later replaced by geologist Harrison Schmitt when the primary crew for Apollo 17 was selected. Schmitt had been crewed with Dick Gordon in anticipation for Apollo 18. But when Apollo 18 was canceled, Schmitt bumped Engle, leaving Gordon as the last Apollo astronaut who had trained extensively for lunar exploration without ever getting a chance to fly a lunar landing.
People who flew around the Moon without landing
On each of the missions listed above one astronaut orbited the Moon while the other two landed. In addition each of the Apollo 8, Apollo 10, and Apollo 13 missions had a three-man crew and closely encountered the Moon (entering orbit in the case of the former two missions, while Apollo 13 only passed around it). Thus twelve more people have been within a few hundred kilometers of the Moon (along with Young and Cernan who flew out to the Moon and back without landing, but landed on subsequent missions):
Apollo 8 was the first manned mission to reach the Moon (Frank Borman, center)
Backup crewmembers who never flew an Apollo flight
Each Apollo flight had a backup crew who trained to carry out the mission if the original crew was unable to fly. Only one backup crew member was ever used: Jack Swigert switched places with Ken Mattingly after Mattingly had been exposed to German measles a few days prior to the launch of Apollo 13. (Mattingly later flew aboard Apollo 16). However, shortly before the launch of Apollo 17, Eugene Cernan badly injured his leg playing softball and only just recovered in time for the mission. Had he been unable to fly he would have been replaced by back-up commander John Young, who would have become the only man to walk on the moon twice and would have done so on consecutive missions.
Gordon Cooper - backup commander for Apollo 10 - lost the primary commander slot on Apollo 13 to Alan Shepard, and resigned from NASA in 1970.
Don Lind - backup command module pilot for Skylab 3 and Skylab 4 (he also may have been slated to land on the moon with Apollo 21 if missions beyond Apollo 20 had been planned). He and Vance Brand were slated for the Skylab Rescue mission which was cancelled in late 1973 after the Apollo CSM aboard Skylab 3 had its thruster issue resolved. Lind later flew on the space shuttle mission STS-51-B.
Astronauts who flew on Apollo, listed by class
A chart showing astronaut assignments leading up to and during the Apollo era.
^Detailed Biographies of Apollo I Crew - Gus Grissom[1], Mary C. Zornio, NASA, accessed July 19, 2006.
^ This date is based on GMT. Americans alive at the time remember it as the night of July 20, 1969 (Armstrong set foot on the Moon at 10:56 p.m. Eastern Daylight Time), but the official NASA chronology was kept in GMT, so the first step was 2:56 a.m. on the 21st: [2]
^ abApollo 18 through 20 - The Cancelled Missions[3], Dr. David R. Williams, NASA, accessed July 19, 2006.