NASA demonstrates successful unmanned lander under onboard computer guidance
By Steven Siceloff, NASA’s Kennedy Space Center, Fla. A test flight of new guidance system on Morpheus was successful on April 24, 2014. A set of sensors to mapped out a 65-yard square of boulder-sized hazards and pick out a safe place to land.
Mounted to an uncrewed prototype lander called Morpheus that flies autonomously several hundred feet above the ground, the sensor system will had 10 seconds to do its work: six seconds really, as it will take four seconds to map the area before choosing a landing site.
The Morpheus lander ignites its methane and oxygen-powered engine and lifts off to begin a free flight test at NASA’s Kennedy Space Center in Florida. The Johnson Space Center-based project is testing new technologies in propulsion and guidance systems in the unique testbed.
The Morpheus/ALHAT team successfully completed Free Flight 11 at the KSC Shuttle Landing Facility (SLF) on Thursday, 24-Apr-2014, the Bravo vehicle’s 9th and the ALHAT system’s 2nd free flight test.
In FF11, ALHAT operated in open-loop mode, imaging the Hazard Field and calculating navigation solutions in real-time during flight, though not yet navigating the vehicle, meaning Bravo autonomously flew a pre-programmed trajectory as before.
ALHAT engineers will use this flight data to continue tuning and improving their system performance. Successful open-loop ALHAT flights, including FF12 next week, will lead to closed-loop ALHAT free flights planned for late May, in which ALHAT will “take the stick”, diverting Bravo from an initial “unsafe” landing point and navigating to a safe landing site within the Hazard Field.
A free-flight test of the Morpheus prototype lander conducted April 24 at the Shuttle Landing Facility at NASA’s Kennedy Space Center in Florida. The 98-second test began with the Morpheus lander launching from the ground over a flame trench and ascending more than 800 feet at a peak speed of 36 mph.
The sensor system is a 400-pound set of computers and three instruments called ALHAT, short for Autonomous Landing and Hazard Avoidance Technology.
AHALT guidance system on Morpheus
The sensor package and a host of technologies introduced by the lander may find themselves instrumental in the success of future missions to other worlds – perhaps propelling a descent stage on a spacecraft landing people on Mars.
That’s a big dream for the two small projects called Morpheus and ALHAT.
Morpheus is the lander – a 10-foot-diameter, 2,400-pound four-legged metal frame holding four spheres of propellant that feed into a single, 5,300-pound-thrust engine. They were developed in the Advanced Exploration Systems Division of the agency’s Human Exploration and Operations Mission Directorate. The branch pioneers new approaches for rapidly developing prototype systems, demonstrating key capabilities and validating operational concepts for future human missions beyond Earth’s orbit.
“I generally don’t sleep much the night before a flight,” said Jon Olansen, project manager for Morpheus, which is based at NASA’s Johnson Space Center in Houston. “But the team has really done a fantastic job of trying to tease out potential issues and mitigate them. I have tremendous faith in the team.”
Just as during a spaceflight, the lander controls itself once it’s launched.
“The only thing we do in the control center is push the go button and watch the data,” Olansen said.
Morpheus is filled with innovations, including an engine that burns methane mixed with oxygen, which has also, for the first time, been coupled with smaller roll control jets using the same propellants. Methane is considered an earth-friendly fuel and its importance in spaceflight is that it can be stored in space without boiling off like hydrogen. It’s also a chemical that has been seen by robot scouts surveying the moon and Mars.
Morpheus on landing approach
“We know these technologies have a place in the future of spaceflight,” Olansen said.
Bolted to different parts of the lander, the suite of sensors surveys the target landing area, identifies safe landing sites, and then uses three methods to tell the lander where it needs to go to avoid rocks or slopes or other hazards.
“We’ve been working a long time, eight years, to prove we can do autonomous, precision landing and hazard avoidance and guidance,” said Chirold Epp, project manager for ALHAT. “We really need to show the world that everything we’ve been advertising for eight years works.”
The technological advancements have come with the work of a team that comprises people from seven NASA field centers.
“The opportunity to take people from seven different centers and get them to work together on what is a relatively small project really is phenomenal,” Olansen said.
Thursday’s free flight is an open-loop test, which means Morpheus’ own flight computer flew the lander above 800 feet before heading several hundred feet away to the landing field and landing softly on a predetermined pad. While this is happening, the ALHAT system employed its flash Lidar system, a laser altimeter and a Doppler velocimeter – think of it as a super-accurate speedometer for spacecraft – to scan the field and pick out the best place to land.
The benefit of the hazard avoidance system is that it gives spacecraft far more flexibility to land accurately and to land on worlds that are not as well-studied as Mars and the moon. The ALHAT team is shooting for a system that can land within 10 feet of a given spot, a big improvement on the current best of about 270 feet.
Morpheus during flight April 24, 2014
The precision isn’t academic – it could be the difference between setting down on a stable plateau or tipping over into a ravine.
A successful flight Thursday clears the way for the next important step in this development: closed-loop flights that turn over control of the lander to the ALHAT system, letting it tell the lander where it needs to park.
“We’ve done airplane tests, helicopter tests, but this is the first time we’ve been in this environment,” Epp said. “Free flight 10 gave us tremendous information. Some things didn’t work quite right and other things worked quite well. Everything worked to some degree. So we go back and we fix it and we test it again.”
“We’ve already achieved an awful lot with this project,” Olansen said. “We just need to wrap up well and get the closed-loop flights accomplished.”
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