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Autonomous Landing Hazard Avoidance Technology (ALHAT)
"It is the business of the future to be dangerous; and it is among the merits of science that it equips the future for its duties."
-- Alfred North Whitehead, 20th century British mathematician

Future expeditions to destinations across the solar system will require robotic and human explorers to land near specific resources -- many of them situated in potentially hazardous terrain. To that end, NASA researchers and their partners are working to equip a new generation of hardy planetary landers with the ability to automatically recognize their desired landing site, assess any and all potential landing hazards and adjust accordingly as they descend to the surface. Once proven, this technology could dramatically improve the safety and versatility of future robotic, cargo and crewed planetary descent vehicles -- opening up a host of new destinations and making it easier for human explorers to reach them.

The Autonomous Landing and Hazard Avoidance Technology (ALHAT) project is developing advanced technologies vital to achieving this real-time capability. These technologies include surface-tracking sensors which very precisely measure spacecraft altitude and velocity relative to the planetary surface and actively measure the topography or roughness of the landing area. High-speed, high-volume processors combine ALHAT algorithms with this sensor data to navigate to what's known as the "pre-mission landing aim point," where the technology will determine safe landing areas close to this point. The spacecraft is then navigated to a safe area close to the landing aim point for touchdown. This entire process is done autonomously with automated guidance, navigation and control software onboard the spacecraft.

Led by NASA's Johnson Space Center in Houston, the ALHAT team developed these technologies, and in fall 2011 will integrate and ground-test them at NASA's Langley Research Center in Hampton, Va. Following successful integration and ground testing, the systems will be shipped to the Johnson Center to be integrated with NASA's Morpheus Vertical Test Bed robotic lander prototype to conduct ground and hop flight tests. Integration and ground testing will include some short hop flights.

After successful completion of this activity, the Morpheus vehicle and the ALHAT system will be shipped to NASA's Kennedy Space Center, Fla., in summer 2012. There, the test article will undertake autonomous flights from altitudes of approximately 1,640 feet and slant range to a surface hazard field of approximately 3,280 feet. The ALHAT system will autonomously determine the safe landing areas in the field and navigate Morpheus to a controlled safe landing.

ALHAT: Key Mission Facts
  • The Autonomous Landing and Hazard Avoidance Technology project will provide a state-of-the-art automated descent and landing system for planetary lander craft.
  • Precision landing will be based on a sophisticated, surface-tracking sensor suite with real-time hazard avoidance capabilities -- assessing altitude and velocity of the descending vehicle and the topography of the landing site.
  • ALHAT algorithms combined with sensor date will navigate the descending craft to the "pre-mission landing aim point," where it will quickly and autonomously identify safe landing areas and help guide the craft to touchdown.
  • The technology provides an unprecedented procedure for safe planetary landing procedures -- for future crewed as well as robotic missions.
  • The technology works in any lighting conditions -- from the harsh glare of an unshielded sun to the cloudy, gaseous murk of a distant solar system body.