To this retired commander, the ISS was the last good bond between the U.S. and Russia

A Soyuz spacecraft docked to the International Space Station in April 2014. (Terry Virts/NASA)

In 1975, a handshake in space heralded an era of cooperation between unlikely partners.

The Apollo-Soyuz mission was the first joint space mission between the U.S. and Soviet space agencies. Spacecraft from each country docked in orbit, and the world watched as Soviet cosmonauts and American astronauts embraced more than 100 miles from Earth. The mission was a powerful symbol of de-escalation after years of Cold War geopolitical tensions.