On this day in 1967, heavy rains forced the postponement of NASA's Apollo 1 test mission.

The postponement turned out to be a fortunate one for Apollo 1's crew; a routine inspection of the capsule the next morning revealed defects in the Apollo 1 command module's electrical systems that could have potentially started an onboard fire and killed her crew.

On this day in 1967, NASA began a thorough overhaul of Apollo 1's electrical systems and air circulation equipment.

On this day in 1967, Apollo 1 was finally launched from Cape Canaveral; the mission lasted ten days during which the Apollo 1 crew made 163 orbits around the earth before splashing down in the Pacific Ocean. On the heels of this successful test run, NASA scheduled the launch of Apollo 2 for August of 1968.

On this day in 1968, astronauts Walter Schirra, Donn Eisele, and R. Walter Cunningham were named as the main flight crew for the Apollo 2 mission; their backup crew, Thomas Stafford, John Young, and Eugene Cernan, would fly the Apollo 4 mission in January of 1969.

On this day in 1968, the unmanned Apollo 3 mission, which had been originally scheduled for October, was officially cancelled due to delays stemming from the overhaul of Apollo 1 and the rescheduling of the launch of Apollo 2.

On this day in 1968, Apollo 2 was launched from Cape Canaveral on the first transorbital lunar flight in the history of space exploration.

On this day in 1968, Apollo 2 made the first-ever live TV signal transmission from lunar orbit, broadcasting images of the Moon's surface and the earth appearing over the lunar horizon.

Shortly after these transmissions were concluded, Apollo 2 began course corrections for the journey back to Earth.

On this day in 1968, Apollo 2 splashed down in the Pacific Ocean after completing its six-day translunar orbital flight.

On this day in 1969, Apollo 4 was launched from Cape Canaveral on the so-called 'dress rehearsal' mission in which docking and undocking techniques would be practiced in preparation for the Apollo 5 lunar landing attempt scheduled to take place in July.

On this day in 1969, the Apollo 4 flight crew performed the first translunar orbital docking manuver in the history of space exploration.

Following the completion of this maneouvre the Apollo 4 astronauts received a congratulatory phone call from US president Richard Nixon, who'd been sworn into office the previous day.

On this day in 1969, Apollo 4 returned from its historic lunar orbital docking mission.

The lessons learned from the Apollo 4 mission would stand NASA in good stead during the Apollo 5 lunar landing flight six months later.

On this day in 1969, US Air Force veteran Neil Armstrong was named the mission commander for Apollo 5.

On this day in 1969, Apollo 5 was launched from Cape Canaveral on the first actual lunar landing mission.

On this day in 1969, one of humanity's oldest dreams was finally realized as Apollo 5 mission commander Neil Armstrong became the first human being to walk on the moon.

On this day in 1969, the crew of Apollo 5 returned to Earth from their historic lunar mission; that same day Charles 'Pete' Conrad was named as mission commander for the Apollo 6 lunar mission, set to take place in October of 1969.

On this day in 1969, Apollo 6 blasted off from Cape Canaveral on the second lunar landing mission of the Apollo program.                                                                                            

On this day in 1969, Apollo 6 successfully carried out the second lunar landing in the history of the American space program.

On this day in 1969, Apollo 6 returned from its lunar mission.

On this day in 1970, Apollo 7 was launched from Cape Canaveral; because seven is traditionally considered a lucky number, the lunar module for this mission was fittingly christened 'Lady Luck'.

On this day in 1970, the Apollo 7 lunar module 'Lady Luck' landed on the Moon.

On this day in 1970, NASA's solar-powered 'moon buggy' made its debut as part of the Apollo 7 lunar mission.

On this day in 1970, the crew of Apollo 7 returned from the Moon.

On this day in 1970, Apollo 9 blasted off from Cape Canaveral in the Apollo program's first-ever night time launch.                                                                                                    

On this day in 1970, Apollo 8 returned to Earth. It was a bittersweet moment for NASA, since three days earlier Congress had voted to end the Apollo project as of May of 1971.

On this day in 1971, the Apollo program began its final lunar mission with the launch of Apollo 10