New technologies being developed at NASA will help spacecraft land safely and accurately on the surface of a celestial body deep in the solar system. The agency's Autonomous Landing Hazard Avoidance Technology (ALHAT), which gives a spacecraft the ability to land autonomously on surfaces full of hazards, recently completed a series of tether tests at NASA's Johnson Space Center in Houston, proving that components of the technology work together seamlessly.
The ALHAT system was integrated onto the Morpheus vertical test bed demonstrating new green propellant propulsion technologies, which flew while tethered to a crane for safety. The ALHAT system passed the tethered test on Morpheus with flying colors.
Led by engineers at Johnson and supported by NASA's Jet Propulsion Laboratory in Pasadena, Calif., and Langley Research Center in Hampton, Va., ALHAT uses laser sensors and high speed computing to locate and avoid obstacles on the landing surface in real time. Obstacles may include anything from steep slopes to craters and rocks. The technology provides spacecraft with landing site recommendations in order to provide an automated and accurate landing.
The flash lidar technology creates a three-dimensional elevation map of the landing terrain and provides distance to the landing site. The goal is to detect basketball-sized objects from a kilometer away. The Doppler lidar technology measures altitude and velocity relative to the ground. The laser altimeter provides range measurement data very early in the landing phase.
All of the components of the ALHAT technology were put to the test.
“Morpheus tether testing is the first chance the ALHAT team has gotten to operate our system on the new Morpheus vehicle during a flight, “said NASA engineer Kevin Kempton. “This test demonstrates that the ALHAT system can correctly communicate with avionics on the Morpheus vehicle and also that it can operate in the Morpheus flight environments. Successful testing provides a lot of confidence that we are ready for the free flight demonstrations over the hazard field at NASA's Kennedy Space Center in Florida this fall.”
The next step will be untethered testing at Kennedy.
“(Kennedy) provides a test field built out of rocks to simulate landing on Mars and is ideal for untethered testing of our ALHAT technology,” said NASA Langley systems engineer, Anna Noe.
Testing will continue to emphasize how ALHAT provides a wealth of technical advantages for future NASA missions.
“Historically, missions have limited their landing sites to really benign terrain so that they could improve the chances of a successful landing,” Kempton explained.
ALHAT may change that.
ALHAT technology can help human pilots by providing much better situational awareness when landing their vehicle. The team has high hopes and confidence that the upcoming testing at Kennedy will prove successful, changing ALHAT’s focus from ‘getting it ready’ to ‘boldly going.’
ALHAT and Morpheus are projects in NASA's Advanced Exploration Systems Program that is developing and demonstrating new capabilities to enable future human exploration missions. The agency is also using the smaller Mighty Eagle lander being tested at NASA's Marshall Space Flight Center in Huntsville, Ala., to mature the technology needed to develop and new generation of small, smart versatile robotic landers capable of achieving scientific and exploration goals on the surface of planetary bodies.
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