white EVA visor assembly. Specifications Name: Apollo 15-17 EMU Manufacturer: ILC Dover (Pressure Suit Assembly) Hamilton Standard (Primary Life Support System) Missions: Apollo 15-17 Function: Intra-vehicular activity (IVA), orbital Extra-vehicular activity and terrestrial Extra-vehicular activity (EVA) Operating Pressure: 3.7 psi (25.5 kPa) IVA Suit Mass: 64.6 lb (29.3 kg) EVA Suit Mass: 78 lb (35.4 kg) Total EVA Suit Mass: 212 lb (96.2 kg) Primary Life Support: 7 hours (420 minutes) Backup Life Support: 30 minutes Skylab EMU The American space station Skylab had three crewed flights. To minimize program costs, NASA elected to fund ILC Dover for modifications to the mid-entry Apollo A7LB EV PSA design to reduce costs and use an umbilical system named the Astronaut Life Support Assembly (ALSA) to allow extra-vehicular activities. AiResearch won the competition for the ALSA. The result was the Skylab EMU. During launch, the space station was damaged. The Skylab EMUs enabled emergency repair and outfitting tasks that permitted the program to conduct its long duration crewed missions and experiments. Skylab returned to all the crew members having the same configuration suits. With the exception of the Orbital Workshop (OWS) repairs carried out by Skylab 2 and Skylab 3, all of the Skylab EVAs were conducted in connection to the routine maintenance carried out on the Apollo Telescope Mount, which housed the station's solar telescopes. Because of the short duration of those EVAs, and as a need to protect the delicate instruments, the Apollo lunar EVA backpack was replaced with an umbilical assembly designed to incorporate both breathing air (Skylab's atmosphere was 74% oxygen and 26% nitrogen at 5 psi) and liquid water for cooling. The assembly was worn on the astronaut's waist and served as the interface between the umbilical and the suit. An emergency oxygen pack was strapped to the wearer's right thigh and was able to supply a 30-minute emergency supply of pure oxygen in the case of umbilical failure. Another unique feature of the Skylab EMU was its simplified EVA visor assembly that did not include an insulated thermal cover over the outer visor shell. There were three crewed Skylab flights. All three missions included "space walks." Specifications Name: Skylab EMU Manufacturer: ILC Dover (Pressure Suit Assembly) and AiResearch (bought by AlliedSignal Corporation)(Astronaut Life Support Assembly) Missions: Skylab 2-4 Function: Intra-vehicular activity (IVA) and orbital Extra-vehicular activity (EVA) Operating Pressure: 3.7 psi (25.5 kPa) IVA Suit Mass: 64.6