The Soviet Union and USA made a plan to do a joint manned mission to Mars during the cold war, but Reagan backed out!

Early in his presidency, John F. Kennedy made repeated attempts to engage the Soviet Union in space cooperation. Khrushchev, still persuaded of the eternal supremacy of Soviet rocketry, was not moved. Less than three months after Kennedy’s inauguration, on April 12, 1961, Soviet cosmonaut Yuri Gagarin became the first human to escape Earth’s gravity. In the aftermath of his brief flight, the piloted component of the Soviet space program rapidly grew to become indisputably dominant over any other type of space activity.

Official Soviet propaganda was obsessed with everything that happened in orbit, including elaborate descriptions of the cosmonauts’ menu at their last breakfast and all of the details of their physical exercise program. Every launch produced several more “Heroes of the Soviet Union,” and more photographs of space superstars embraced by Khrushchev. At the same time, the Soviets were left far behind in other key areas of space technology.

Despite the continued space competition between the United States and U.S.S.R., Khrushchev sent Kennedy a letter raising the possibility of space cooperation on a modest level after John Glenn became the first American to orbit Earth on Feb. 20, 1962. That led to two rounds of discussions between NASA’s Deputy Administrator Hugh Dryden and Soviet academician Blagonravov. Eventually the Soviet Union agreed to a joint manned mission to Mars. Ronald Reagan became president, though and he refused to sign off on the deal.