VentureStar

VentureStar was a single-stage-to-orbit reusable launch system proposed by Lockheed Martin and funded by the U.S. government to replace the Space Shuttle. It was meant to be an uncrewed spaceplane that would launch vertically and return to Earth as an airplane, putting satellites into orbit for about 2,000 dollars a kilogram, a tenth of the Shuttle's cost, with a wingspan of 68 feet, a length of 127 feet and a weight of roughly 1,000 tonnes. It would have burned only liquid hydrogen and liquid oxygen in linear aerospike engines and carried a metallic thermal protection system instead of ceramic tiles. VentureStar was essentially a bigger version of the X-33 demonstrator and was never produced: the X-33 failed in testing, chiefly over its composite hydrogen tank, and funding was cancelled in 2001.