Apollo astronaut Ronald E. Evans in an inner pressure suit. This is the inside layer of the space suit which will later be used by Evans on Apollo 17, the last manned mission to the Moon, in December 1972. The space suit is designed to protect an astronaut by creating an artificial environment which limits radiation and the effects of vacuum and temperature. The pressure suit was used to stabilise the pressure, which could be kept lower than atmospheric pressure because the spacesuit does not need to carry nitrogen. Evans is testing the pressure suit at NASA's space suit contractor in Delaware, USA.