Multiple choice general knowledge science & technology What is the name of the sub-scale version of the Venturestar? X-33 X-34 X-38 X-40 Reveal answer Fill a bubble to check yourself A Correct answer Explanation The Lockheed Martin X-33 was an unmanned, sub-scale technology demonstrator for the VentureStar, a proposed reusable launch vehicle. The project was intended to test the 'single-stage-to-orbit' concept before being canceled in 2001.