page_title: Autonomous Landing Hazard Avoidance Technology
section_title: Testing
hierarchical_section_title: Autonomous Landing Hazard Avoidance Technology / Testing
caption_attribution_description: English: The ALHAT LIDAR imaging system detected and identified the target as a hazard whilst flying as part of a Morpheus lander
context_page_description: Autonomous Landing Hazard Avoidance Technology is technology NASA is developing to autonomously land spacecraft on the Moon, Mars or even an asteroid.
  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.
  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 and supported by Jet Propulsion Laboratory and Langley Research Center.
context_section_description: A variety of field tests have been performed on the ALHAT equipment.  The tests have been designed to demonstrate that the ALHAT equipment has reached TRL 6.
  The ALHAT's ability to detect items larger than a baseball from a distance of 2,500 feet (760 m) whilst moving was tested by placing the system on a truck.  The ALHAT was able to image and navigate while the team were driving.
   
  The larger version of ALHAT was tested using helicopter flights at NASA's Dryden Flight Research Center, Edwards, California in 2010.
  A lunar terrain field was constructed at Kennedy Space Centre (KSC) for ALHAT on Morpheus lander testing. The field has an array of different terrain features to test ALHAT's ability to detect hazards.  Initial testing used the lightweight ALHAT on a helicopter.
  A helicopter test of the integrated ALHAT System with the Morpheus avionics was performed over the ALHAT planetary hazard field at KSC. The KSC helicopter tests included flight profiles approximating planetary approaches, with the entire ALHAT system interfaced with all appropriate Morpheus subsystems and operated in real-time. During these helicopter flights, the ALHAT system imaged the simulated lunar terrain. Use of a helicopter permitted most but not all of the testing to be performed. Good data was obtained from all of the sensors. All of the problems detected have been identified and fixed to support future testing on the Morpheus Lander.
  In July 2013 the integration of ALHAT with the Project Morpheus lander version 1.5 hardware resumed.  Tests included placing the lander on blocks to verify that the ALHAT Inertial Measurement Unit (IMU) worked when tilted.  Tilting tests were performed at several different heights and directions.
  On July 23, 2013 the Morpheus/ALHAT team successfully completed Tethered Test #26 with the ALHAT integrated into Morpheus' Bravo vehicle.   All test objectives were met including ALHAT tracking & imaging.  Imaging was performed at several heights.  An example of the imaging produced by the LIDAR can be seen in the picture.
  On July 27, 2013 Bravo and ALHAT flew again in TT27.  The ALHAT's tracking & imaging meeting all of the test objectives.
  During the rest of 2013 and early 2014 the ALHAT was removed from Bravo whilst various enhancements were made to the lander and flight tested.  In March 2014 the ALHAT was installed back into the lander.  On March 27, 2014 the assembly successfully performed a tethered test hovering at a variety of heights.  The ALHAT's laser head can be seen scanning the area in the box during TT34 at the top right of this video.  Morpheus Free Flight 10 took place on April 2, 2014.  The ALHAT was in open loop mode.  As well as the flight this video includes shots from a witness camera mounted and carefully aligned to the laser scanning head showing what the laser saw, but in the visible spectrum.  Confirming that the hazard field was scanned.
  On April 24, 2014 Free Flight 11 (FF11) was successfully completed at the KSC Shuttle Landing Facility (SLF). In FF11, as in FF10, ALHAT operated in open-loop mode, imaging the Hazard Field and calculating navigation solutions in real time during the flight. The equipment was 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.
  A swing test was performed on April 28, 2014 to obtain accurate data on ALHAT's 3-beam Navigation Doppler Lidar to calibrate and confirm its range and velocity measurements.  Free Flight 12 on April 30, 2014 was a repeat of the previous flight except the Lander was targeting the HDS identified landing site.
  Free Flight 13 on May 22, 2014.  First flight of ALHAT and Morpheus Lander with the ALHAT having closed loop control of the lander.  The correct landing location was identified and flown to.  There was a disagreement between the ALHAT and the Morpheus's guidance, navigation, and control over the lander's current location.
  Free Flight 14 on May 28, 2014 took place at night.  The ALHA
caption: The ALHAT LIDAR imaging system detected and identified the target as a hazard whilst flying as part of a Morpheus lander
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