Prior to 2013, successful water landings of launch vehicles were not attempted, while periodic water landings of space capsules have been accomplished since 1961. The vast majority of space launch vehicles take off vertically and are destroyed on falling back to earth. Exceptions include suborbital vertical-landing vehicles (e.g., Masten Xoie or the Armadillo Aerospace' Lunar Lander Challenge vehicle), and the spaceplanes that use the vertical takeoff, horizontal landing (VTHL) approach (e.g., the Space Shuttle, or the USAF X-37) which have landing gear to enable runway landings.[50] Each vertical-takeoff spaceflight system to date has relied on expendable boosters to begin each ascent to orbital velocity.