NASA will next year field-test the laser altimeter, camera and flash light detection and ranging (lidar) technology that its Altair Lunar Lander could use to make a soft landing on the Moon's surface in 2020.

The testing is part of NASA's Autonomous Landing and Hazard Avoidance Technology (ALHAT) project. ALHAT is developing a precision landing and hazard avoidance system for both robotic and crewed versions of Altair. A flash lidar field test using helicopter flights in Death Valley, California was performed in May.

ALHAT has to enable precision landing - touching down within 30m (98.3ft) of a target - be able to detect a vertical height change in the terrain of 300mm (11.8in) and slopes of more than 5°. While operating automatically ALHAT will also accept supervisory control from crew.

NASA Johnson Space Center-based ALHAT project manager Chirold Epp presented its progress at the American Institute of Aeronautics and Astronautics' Space 2008 conference in San Diego in September. In his presentation he said that ALHAT must develop to a technology readiness level of six an autonomous lunar landing guidance, navigation and control and sensing system. He said this must be capable of identifying and avoiding surface hazards to enable a safe precision landing to within tens of metres of designated landing sites under any lighting conditions.

A technology readiness level of six is a successful demonstration in a "relative environment". Leaving the Orion crew exploration vehicle in its 100km (62 miles) lunar orbit, Altair's powered descent is expected to take up to 10min and start at 15km - the same as in the Apollo programme. Previous ALHAT documents have shown an 18km altitude decision point for powered descent.

Source: Flight International