The Apollo space program sent twelve American astronauts to the moon, where no human being had been before or has been since. During the seven manned mission to the moon, only Apollo 13 failed to make a lunar landing when an accident en route to the Moon forced the crew to abandon the mission and return to Earth after reaching lunar orbit. The last flight, Apollo 17, occurred in December 1972.
Over the next three years after Apollo 11, the lunar missions conducted increasingly sophisticated studies of the Moon, yielding new scientific insights into the evolution of our celestial neighbor. Each mission explored new areas of the lunar surface and left behind nuclear-powered scientific instruments that continued to send data back to Earth years after the last astronaut left the Moon. And beginning with Apollo 15, astronauts conducted their explorations with the aid of a Moon car, a Lunar Roving Vehicle, that allowed them to travel and work miles away from their Lunar Module.
But despite these remarkable exploits of discovery and the drama of Apollo 13's near-disaster the nation gradually lost interest in a program of lunar exploration. With Apollo 11, we had fulfilled President Kennedy's 1961 challenge and beated the Soviet Union in achieving a historic feat of exploration. By the mid-1970s the marvels of Apollo—the Saturn V rockets and the spacecraft—were set aside and the national expertise that made them possible was redirected. A successful space program now had to find a new purpose in a new era.
After Apollo and a decade of concentrated national effort to meet President Kennedy's Moon challenge, the American human spaceflight program moved toward new, less ambitious goals. For many citizens landing on the Moon ended the space race and diminished support for expensive programs of human space exploration. Advocates of exploration expected the Apollo missions to be the beginning of an era in which humans would move out into space, to bases on the Moon and space stations in Earth orbit, perhaps on to Mars. Others questioned whether costly human spaceflight should continue at all, now that the race was won.
This shift in public and political sentiment resulted in a modest program of human space activity—compared to the hey-day of the lunar landings. As the last lunar mission, Apollo 17, was completed in 1972, the nation settled in for a quieter era of space exploration. Two programs, using leftover Apollo rockets and spacecraft no longer need for moon journeys, symbolized this new era: Skylab and the Apollo-Soyuz Test Project.
Skylab, an experimental habitat built from the third-stage of a Saturn V, was the first American space station. But in an era of lower space budgets and waning public interest, it was only intended as a temporary, not a permanent, home in space. Skylab was occupied by astronauts only three times over 1973 and 1974. The Apollo-Soyuz Test Project (ASTP) marked a real and symbolic end to Apollo and the space race of the 1960s. To highlight reduced international tensions the United States and Soviet Union undertook, after years of intense rivalry, their first cooperative mission in space. In 1975 an American and a Soviet spacecraft rendezvoused in space as a symbol of the two countries improved relations. The crews visited each other's spacecraft, shared meals, and worked on various tasks during several days together in space.
Skylab and ASTP, successful and significant undertakings, seemed a quiet conclusion to Apollo, arguably the boldest and most dramatic adventure in history.
Skylab was a manned space station launched into Earth orbit by the United States in May 1973. It was made from the third stage of a Saturn V launch vehicle. A crew of three astronauts occupied Skylab during each of three missions. The longest mission, which ended in February 1974, lasted almost three months.
This Apollo command module is identical to those used during the Apollo Program. It was used to ferry the crew of the last Skylab mission, astronauts Gerald P. Carr, Edward G. Gibson, and William R. Pogue, to the Skylab Orbital Workshop and back to Earth again. The Skylab 4 crew lived in the Skylab for 84 days, from Nov. 16, 1973 to Feb. 8, 1974. The crew performed numerous experiments and demonstrated that humans can live and work in space for long periods of time.
At the height of detente in the early 1970s, George Low, Deputy Administrator under Thomas Paine, began negotiating with Soviet space officials for a joint endeavor in space. After the appointment of James C. Fletcher as Administrator in April 1971, Low continued the negotiations until an agreement was reached and signed by President Richard Nixon and Soviet Premier Alexei Kosygin as part of the SALT accords of 1972.
The Apollo Soyuz Test Project flight took place in July 1975. Three U.S. astronauts and two Soviet cosmonauts exchanged these flags as a symbol of the first international manned space venture.