A Soviet spacesuit introduced in 1978 for cosmonauts about to return from 126 days on the Salyut 6 space station mission. It was a low-pressure suit that forced the body's blood into the legs, an effect similar to that of Earth's gravity. This caused the cardiovascular system, slowed by weightlessness, to work harder and strengthen the heart in preparation for a return to gravity. Similar units were worn regularly by crews on the Mir space station.