A spacesuit is a complex system of garments, equipment, and environmental systems designed to keep a person alive and comfortable in the harsh environment of outer space. Related preceding technologies include the gas mask used in WWII, the oxygen mask used by pilots of high flying bombers in WWII, the high altitude or vacuum suit required by pilots of the Lockheed U-2 and SR-71 Blackbird, the diving suit, rebreather and scuba diving gear.Photo credit: Jawed Karim