With only cosmonaut Vladimir Shatalov aboard, the Soviet Union launches Soyuz 4 into Earth orbit. Another manned vehicle, Soyuz 5, is launched the next day, and the two vehicles dock in orbit, the first docking of two manned spacecraft. Alexei Yeliseyev and Yevgeny Khrunov perform a spacewalk to leave Soyuz 5 and board Soyuz 4 for the return home (though the two capsules have primitive docking hardware, they do not have a docking tunnel or airlocks). Soyuz 4 makes a safe landing after two days in orbit – which is more than can be said for its sister ship.
