JPL tested its G-FOLD landing system Sept. 20, 2013 at Mojave Air and Space Port, with UT Austin; Masten Space; and NASA's Flight Opportunities Program at NASA Dryden.
Transcript:G-FOLD Diversion Test
January 17, 2014
Sound: Unintelligible radio chatter.
Kyle Nyberg: As the Masten engineering team performs the final system checks on Xombie, JPL's new Fuel-Optimal Large Divert Guidance Algorithm, known as G-FOLD, is about to get its largest demonstration to date. With support from NASA's Flight Opportunities Program, this ground-breaking project enables JPL to validate robust landing technology. This Google Earth visualization is created from the actual trajectory data recorded by Xombie in flight. The trajectory may look simple, but this flight represented an unprecedented achievement in autonomous rocket technology. The half-mile translation across the desert was, in fact, a spontaneous landing diversion in which the rocket was commanded to abort its initial nearby landing spot during final approach, aggressively change direction and begin following a new trajectory that was first calculated only one second earlier. The G-FOLD computer calculated this new trajectory in mid-air in real time, choosing a new landing site in the distance and optimizing the path through the sky to burn the least amount of fuel possible. Although the engineering teams knew the intended landing diversion before launch, the vehicle's systems received the updated instructions mid-flight, with no advance warning. Once commanded to change direction, the system instantly throttled up the engine and aimed the vehicle hard over to meet the new objective. This flight was yet another expansion of Xombie's vehicle flight dynamics, reaching a maximum altitude of 1200 feet while flying out-of-plane with the landing pads, then traversing downrange nearly a half mile over the desert floor at more than 50 miles an hour before gently touching down within 9 inches of its target.
Sound: Rocket ignites.
Sound: Rocket flying.
Sound: Fire sounds as rocket shuts down.