1969-10-11 USSR Soyuz 6

A Soyuz 6 First Day Cover from "KNIGA", postmarked in Moscow with a hand cancel on October 22, 1969, signed by Georgy Shonin and Valeri Kubasov.

Soyuz 6 was launched from Baikonur on October 11, 1969, carrying cosmonauts Georgi Shonin and Valeri Kubasov. It was the first of three Soviet crewed spacecraft launched in consecutive days as part of a complex group flight. One of its principal objectives was to test welding techniques in the vacuum of space. Kubasov operated the experimental Vulkan welding apparatus inside the spacecraft's depressurized orbital module, testing several methods that could eventually be useful for construction and repair work aboard future space stations.

Soyuz 6 was also intended to observe and photograph the planned rendezvous and docking of Soyuz 7 and Soyuz 8. However, problems with the rendezvous systems prevented the docking from taking place. The spacecraft nevertheless carried out various engineering, scientific, and biomedical experiments while operating alongside the other two Soyuz spacecraft. Soyuz 6 returned to Earth on October 16, 1969, after 4 days, 22 hours, and 42 minutes in orbit.