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Masten’s Xombie Tests JPL’s G-FOLD Precision Landing Software

Masten Xombie flames during landing

With engineers and officials from NASA’s Jet Propulsion Laboratory watching, Masten Space Systems’ XA-0.1B “Xombie” took to the sky again in the fall of 2013. The flight on Sept. 20 was the conclusion of a test campaign to assess the performance of JPL’s Guidance for Fuel Optimal Large Diverts (G-FOLD) algorithm under mission conditions.

More ambitious than the previous flights, this test had the Xombie rocket initially travel diagonally away from the target landing site after launch. This simulated a worst-case spacecraft landing maneuver and forced the G-FOLD algorithm to calculate, in real time, a flight path that crossed over itself to reach the safe landing site, according to JPL’s Autonomous Descent and Ascent Powered-flight Testbed (ADAPT) team.

Crew wearing sunglasses works on Xombie from a ladder
A member of Masten Space Systems’ ground crew makes final adjustments to the firm’s technology demonstrator rocket before liftoff on the final test flight of JPL’s G-FOLD spacecraft landing flight control software.
NASA / Tom Tschida

“G-FOLD presents a dramatic improvement in our ability to execute large divert maneuvers with limited fuel,” said ADAPT team lead Martin Regehr.

According to team members, the accurately executed half-mile-long (0.8-kilometer), three-dimensional divert showed the potential of what G-FOLD could mean for future space missions. Compared to the software used to land NASA’s Mars Curiosity rover in August 2012, G-FOLD can provide six times more divert range for a lander of that class. Such a capability would be needed for landing on Europa or for human missions to Mars.
The ADAPT team believes that G-FOLD also might reduce the difficulty of future robotic missions to Mars, allowing rovers to land closer to features of interest instead of driving long distances to reach them. A future rover similar to Curiosity might be able to land right next to a target of scientific interest like Mount Sharp instead of driving for a year to get there.

Even though this is the culmination of the current round of testing, JPL’s ADAPT team still has far-reaching plans for G-FOLD and for further tests of other landing technologies.

To further enhance future mission capability, JPL plans to use ADAPT to demonstrate terrain-relative navigation using the Lander Vision System (LVS) together with G-FOLD in 2014.

This effort was performed by JPL, based in Pasadena, Calif., with participation from the University of Texas at Austin; Masten Space Systems, Inc., Mojave, Calif.; and was supported by NASA’s Flight Opportunities Program, managed by NASA’s Dryden Flight Research Center, Edwards, Calif.

Triptych of vehicle lifting off in barren landscape, titled slightly against blue sky, and landing vertically in a similar landscape but different location
From left, Masten Space Systems’ Xombie technology demonstrator lifts off during the final flight test of JPL’s G-FOLD precision flight control algorithm, autonomously diverts to an alternate landing site, and descends for landing at the alternate site.
NASA / Tom Tschida

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NASA Jet Propulsion Laboratory