It was the final flight of the Apollo program that broke new ground in 1975, when two Cold War superpowers came together in an unprecedented cooperative mission in July of that year.
It was the first flight in which spacecraft from different nations docked with each other, bringing a U.S. Apollo spacecraft carrying a crew of three together with a Russian Soyuz spacecraft and its crew of two. The Cold War rivals met in Earth's orbit 35 years ago, on July 17, 1975.
Historic photos and video provided by NASA show the docking and handshake as NASA astronauts Tom Stafford, Vance Brand, and Deke Slayton meet Russian cosmonauts Aleksey Leonov and Valeriy Kubasov.
Pictured is the joint crew for the 1975 Apollo-Soyuz Test Project, with astronaut Thomas P. Stafford (left), commander of the American crew; cosmonaut Aleksey A. Leonov (standing on right), commander of the Soviet crew; astronaut Donald K. Slayton (seated on left), docking module pilot of the American crew; astronaut Vance D. Brand (seated in center), command module pilot of the American crew; and cosmonaut Valeriy N. Kubasov (seated on right), engineer on the Soviet crew.
The Saturn IB rocket lifted off from NASA's Kennedy Space Center in Florida on July 15, 1975, a half hour after the Soyuz launch from Kazakhstan. The Saturn carried Stafford, Brand, and Slayton in an Apollo capsule 7 for their momentous rendezvous with the Soviet crew.
Apollo carried with it into orbit a newly designed interface called the Docking Module, a 3-meter-long, 1.5-meter-wide cylinder that enabled compatibility between the vastly different spacecraft designs. This interface laid the foundation for a standard international docking system.
Once in orbit, according to NASA records, the final maneuvers occurred at 8:51 a.m. EDT July 17 and put the Apollo spacecraft in a 229.4-kilometer circular orbit matching the orbit of the Soviet Soyuz 19.
A few minutes later, command-module pilot Vance D. Brand reported, "We've got Soyuz in the sextant." Voice contact was made soon after. "Hello. Soyuz, Apollo," Apollo commander Thomas P. Stafford said in Russian. Valery Kubasov replied in English, "Hello everybody. Hi to you, Tom and Deke. Hello there, Vance."
This view of the American Apollo spacecraft in orbit was taken from the Soviet Soyuz spacecraft prior to docking.
On the left is the special docking module attached to the Apollo capsule, specifically designed for this mission, that enabled the two spacecraft to join together in orbit.
A commemorative plaque was assembled in orbit by the astronauts and cosmonauts as a symbol of international cooperation in space exploration during a period in history in which the two nations were rarely on friendly political terms.
The American side of the plaque is blue, with English text, while the Soviet side is red, with Russian text.