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Autonomous Landing Hazard Avoidance Technology (ALHAT) is technology NASA is developing to autonomously land spacecraft on the Moon, Mars or even an asteroid.〔〔 (【引用サイトリンク】accessdate=February 8, 2013 )〕 According to the NASA web page on the project, it will provide state-of-the-art automated descent and landing system for planetary lander craft. A surface-tracking sensor suite with real-time hazard avoidance capabilities will assess altitude and velocity of the descending vehicle and the topography of the landing site to permit precision landing. The descending craft will use the ALHAT algorithms combined with sensor data to navigate to the "pre-mission landing aim point," where it will autonomously identify safe landing areas and guide the craft to touchdown. The technology will work in any lighting conditions, from the harsh glare of an unshielded Sun to the cloudy, gaseous murk of a distant Solar System body.〔abridged quotation from: 〕 A landing craft equipped with ALHAT will have the ability to detect and avoid obstacles such as craters, rocks and slopes and land safely and precisely on a surface. The project is led by Johnson Space Center (JSC) and supported by Jet Propulsion Laboratory (JPL) and Langley Research Center.〔 Some of the sensors may also be used to help spacecraft dock.〔 〕 The ALHAT technologies include a Hazard Detection System, a lidar Doppler velocimeter, a laser altimeter, software, sensor algorithms and path-to-space computer processors. These technologies integrate with the lander’s onboard navigation instrumentation.〔 The equipment has a mass of .〔 The instrumentation has been tested by operating from moving vehicles - a truck, NASA's Huey helicopter and the Project Morpheus lander. At the end of testing the project is aiming for the ALHAT equipment to have reached Technology Readiness Level (TRL) 6.〔〔 == Technology == Resources needed by future expeditions will frequently be situated in potentially hazardous terrain, consequently robotic and human explorers need to land safely near to these resources. This requires a new generation of planetary landers with the ability to automatically recognize their desired landing site, assess potential landing hazards and adjust as they descend to the surface.〔 〕 NASA Langley created three lidar (light radar) sensors: the flash lidar, Doppler lidar and high-altitude laser altimeter for the ALHAT project.〔 〕 The flash lidar uses imagery technology to detect objects larger than the size of a basketball on a planetary surface under all lighting conditions. If there is an obstacle, the System will divert the vehicle to a safer landing spot.〔 The three-dimensional camera sensor engine also forms part of the DragonEye space camera used by the Dragon spacecraft to dock with the International Space Station.〔 (【引用サイトリンク】accessdate= February 15, 2013 )〕 The flash lidar flashes a laser and acts like a flash camera permitting the generation of lidar maps and images.〔 The Doppler lidar measures the vehicle's altitude and velocity to precisely land on the surface, and the high-altitude laser altimeter provides data enabling the vehicle to land in the chosen area.〔 The lidar laser technology scans an area for hazards like craters or rocks before the lander touches down. The onboard system uses the data to build a terrain and elevation map of potential landing sites in real time. ALHAT first scans from a high altitude giving the spacecraft sufficient to respond to obstacles or craters at the landing site. Safe sites are designated based on factors including the tilt angle of the surface, the distance and fuel cost to get to a site and the position of the lander’s footpads.〔 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Autonomous Landing Hazard Avoidance Technology」の詳細全文を読む スポンサード リンク
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