How it began
The E. O. Paton Electric Welding Institute in Kyiv began investigations on welding in space in 1963. Under the leadership of Borys Paton it designed an apparatus called Vulkan to test welding outside the atmosphere. In October 1969, during the joint flights of Soyuz 6, 7 and 8, flight engineer Valery Kubasov operated the unit aboard Soyuz 6. The apparatus was designed and built in Kyiv, while the experiment itself took place in orbit on a Soviet spacecraft.
How it works
Vulkan was a cylinder housed in the unpressurized orbital module of the spacecraft, which was open to the vacuum of space. It welded samples of stainless steel and titanium alloys under vacuum and zero gravity. Those two conditions together cannot be reproduced fully in a laboratory on the ground, which is why the test had to be flown.
What changed first
The welds were made successfully, and their quality was reported to be in no way inferior to that of welds made on Earth. The experiment showed that metal could be joined in orbit, a requirement for repairing spacecraft or assembling large structures in space.
What lasted
The Kyiv institute continued the work. In 1979 its Isparitel device was tested aboard the Salyut 6 orbital station to study the evaporation and condensation of materials and the depositing of thin coatings in orbit. In 1984 welding, cutting and coating were carried out in open space with a versatile electron-beam tool, and in the 1980s the institute developed welded structures that could be deployed in space.
