Twenty-Nine Second 'Hop' Tested Closed Loop Thrust Vector And Throttle Control
SpaceX's Grasshopper took a 12-story leap towards full and rapid rocket reusability in a test flight conducted December 17, 2012 at SpaceX’s rocket development facility in McGregor, Texas.
Grasshopper, SpaceX’s vertical takeoff and landing vehicle (VTVL), rose 131 feet, hovered and landed safely on the pad using closed loop thrust vector and throttle control. The total test duration was 29 seconds.
Grasshopper stands 10 stories tall and consists of a Falcon 9 rocket first stage, Merlin 1D engine, four steel landing legs with hydraulic dampers, and a steel support structure.
The 12-story flight marks a significant increase over the height and length of hover of Grasshopper’s previous test flights, which took place earlier this fall. In September, Grasshopper flew to 6 feet, and in November, it flew to 17.7 feet/2 stories including a brief hover.
Testing of Grasshopper will continue with successively more sophisticated flights expected over the next several months.
SpaceX is conducting the tests in three phases, with the first being these low-altitude short-duration flights. According to a draft FAA Environmental Impact Assessment published in 2011, in Phase 2, there would be slightly less propellant loaded, a different thrust profile, and the maximum altitude would be increased to 670 feet, still below Class E Airspace. The mission duration during Phase 2 is again approximately 45 seconds.
The goal of Phase 3 is to verify the Grasshopper RLV’s ability to perform a VTVL mission at higher altitudes and higher ascent speeds and descent speeds. To achieve this, the maximum mission altitude would be increased from 670 feet incrementally up to 11,500 feet. The altitude test sequence likely would be 1,200 feet; 2,500 feet; 5,000 feet; 7,500 feet; and 11,500 feet. The maximum test duration would be approximately 160 seconds. The Grasshopper RLV would land back on the launch pad.
(Image from SpaceX YouTube Video)