VentureStar was a singlestagetoorbit (SSTO) reusable launch system proposed by Lockheed Martin and funded by the U.S. government. The goal was to replace the Space Shuttle by developing a reusable spaceplane that could launch satellites into orbit at a fraction of the cost. Design specifications called for the use of linear aerospike engines that maintain thrust efficiency at all altitudes. VentureStar was essentially a bigger version of the X33 but was not produced after failures with the X33 subscale technology demonstrator test vehicle, funding was cancelled in 2001.


aerospike engine By NASA Marshall Space Flight Center (NASAMSFC) [1], Papa Lima Whiskey (restoration credit) http://nix.ksc.nasa.gov/info;jsession..., CC BYSA 3.0, https://commons.wikimedia.org/w/index...