Flight testing a Real-Time Hazard Detection System for Safe Lunar Landing on the Rocket-Powered Morpheus Vehicle

Abstract

The Hazard Detection System (HDS) is a component of the ALHAT (Autonomous Landing and Hazard Avoidance Technology) sensor suite, which together provide a lander Guidance, Navigation and Control (GN&C) system with the relevant measurements necessary to enable safe precision landing under any lighting conditions. The HDS consists of a stand-alone compute element (CE), an Inertial Measurement Unit (IMU), and a gimbaled flash LIDAR sensor that are used, in real-time, to generate a Digital Elevation Map (DEM) of the landing terrain, detect candidate safe landing sites for the vehicle through Hazard Detection (HD), and generate hazard-relative navigation (HRN) measurements used for safe precision landing. Following an extensive ground and helicopter test campaign, ALHAT was integrated onto the Morpheus rocket-powered terrestrial test vehicle in March 2014. Morpheus and ALHAT then performed five successful free flights at the simulated lunar hazard field constructed at the Shuttle Landing Facility (SLF) at Kennedy Space Center, for the first time testing the full system on a lunar-like approach geometry in a relevant dynamic environment. During these flights, the HDS successfully generated DEMs, correctly identified safe landing sites and provided HRN measurements to the vehicle, marking the first autonomous landing of a NASA rocket-powered vehicle in hazardous terrain. This paper provides a brief overview of the HDS architecture and describes its in-flight performance.

Imaging flash LIDAR for safe landing on solar system bodies and spacecraft rendezvous and docking

“…First approach is scanning the lidar FOV over the target area to generate a mosaic of image frames that can be stitched together to produce a 1M pixels DEM. This approach was successfully implemented and demonstrated by ALHAT in Morpheus flight test using the current 16K pixels lidar 20 . The second approach is Super-Resolution (SR) technique for which the lidar FOV is enlarged to cover the whole area and then blend a sequence of image frames of the same scene to achieve the desired resolution.…”

COBALT: Development of a Platform to Flight Test Lander GN&C Technologies on Suborbital Rockets

“…Reconnaissance maps, however, are of finite resolution, and the resolutions are typically not fine enough to a priori detect small terrain features that would pose a hazard to a small, robotic lander. The addition of an onboard Hazard Detection and Avoidance (HDA) system 5,6 provides local, high-resolution knowledge of the landing terrain during final descent and can be used to implement a small avoidance divert to a safe landing site.…”

Flight testing of terrain-relative navigation and large-divert guidance on a VTVL rocket

“…Results from offline processing of helicopter field test data show position estimation accuracy of less than 90 m. 11 Finally, the ALHAT project has been developing and flight testing precision landing sensors and hazard detection and avoidance (HDA) technology. 12,13,14 Ongoing work is focusing on integrating the navigation Doppler LIDAR sensor developed by the NASA Langley Research Center under ALHAT 15 with the ADAPT payload. Adding HDA functionality, i.e., mapping and analyzing surface terrain during descent to avoid landing on rocks or craters, could be considered in the future.…”