First U.S.-Soviet Joint Issue Stamps
On July 15, 1975, the US and Soviet Union each issued stamps honoring the launch of their Apollo-Soyuz Test Project, their first joint space venture.
After several years of tension and a Space Race to the Moon, the United States and Soviet Union began to adopt a détente policy. This was an easing of strained relations. Out of this policy came the Apollo-Soyuz Test Project.