The Space Shuttle is a manned vehicle, constructed to go from Earth's surface to Earth's orbit and vice versa. Five Space Shuttles have been built: Columbia, Challenger, Discovery, Atlantis and Endeavour. While two of them (Columbia and Challenger) had fatal accidents, three of them are still in use. The first flight was in 1981, and it is planned to use them until 2010.
Eric Knight, founder of UP Aerospace and president of Remarkable Technologies, suggests sending the shuttles on a last journey towards Mars, instead of retiring them in a terrestrial museum. It would be a manned one-way mission. Landing the shuttles on Mars's surface requires additional huge parachutes, for the atmosphere is too thin to support the shuttle's wings.