International space agencies want to maximise the scientific return of planetaryexploration missions with the minimum level of risk. This goal can be achievedby implementing the capability of landing spacecrafts with high precision andsafety nearby known surface targets of interest such as craters, boulders andhills. Innovative guidance, navigation and control technologies are needed toachieve that goal. It requires the capability to identify boulders and slopes on thesurface of the celestial body and react rapidly in order to guide the spacecraft towarda safe region. This capability is known in the literature as Hazard Detectionand Avoidance (HDA). In previous papers presented at various conferences, thedesign of a Lidar-based autonomous planetary landing system and its validationusing software simulators and scaled hardware-in-the-loop simulators were presented.This paper is a continuation of this work and presents the demonstrationat full scale of this technology using helicopter flight test experiments, withLidar measurements processing and HDA software functions operated in realtime using a flight representative Lidar instrument. The first flight test experimentsof this program were performed with success during the month of October2010 and additional flight test campaigns were conducted during September2011 using an upgraded and consolidated version of the design. This paper beginswith a description of the latest design version of the Lidar-based autonomousplanetary landing system. Then, the paper presents the methodologyadopted to validate the interfaces and the performance of the landing system in ascaled and repeatable environment using a robotic test bench, the so-calledLanding Dynamic Test Facility (LDTF). This laboratory environment enables theefficient, low-cost and low-risk validation of the complex landing system beforeproceeding to the more expensive and more risky flight experiments. The paperthen presents the flight test validation methodology using a helicopter on a steepdescent (Mars-like) and shallow descent (Moon-like) trajectory toward terrainswith representative slopes, rocks and boulders. The paper concludes with thepresentation of the flight experiment results and a detailed analysis of theachieved performance.
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