Nine Skylab crewmen manned the Nation's first space station for a total of 171 days during 1973 and 1974. They wore simplified versions of the Apollo spacesuit while doing the historic repair of the Skylab and changing film canisters in the solar observatory cameras. Jammed solar panels and the loss of a micrometeoroid shield during the launch of the Skylab orbital workshop necessitated several spacewalks for freeing the solar panels and for erecting a substitute shield.
The spacesuit changes from Apollo to Skylab included a less expensive to manufacture and lightweight thermal micro-meteoroid over-garment, elimination of the lunar boots, and a simplified and less expensive extravehicular visor assembly over the helmet.
The liquidcooling garment was retained from Apollo, but umbilicals and astronaut life support assembly (ALSA) replaced backpacks for life support during spacewalks.
Apollo-type spacesuits were used again in July 1975 when American astronauts and Soviet cosmonauts rendezvoused and docked in Earth orbit in the joint Apollo-Soyuz Test Project (ASTP) flight. Because no spacewalks were planned, U.S. crewmen were equipped with modified A7LB intra- vehicular Apollo spacesuits fitted with a simple cover layer replacing the thermal micrometeoroid layer.