The Europa Lidar Sensor Assembly
The Europa Lidar Sensor Assembly (ELSA) is a multi-function lidar for landing on objects in our solar system of which we have limited topographic knowledge. Europa is an example object of high interest due to the hypothesis that a water ocean hides beneath its icy surface and possibly containing evidence of life; however, existing images of its surface we have are low-resolution, making it difficult or impossible to plan a safe landing. The ELSA system being presented is designed to provide altimetry from 10 kilometers to 10 meters, a coarse Digital Elevation Model (DEM) generated at a 5-kilometer elevation for site selection, and fine DEM generated at a 500-meter elevation for hazard avoidance. ELSA utilizes a radiation hardened single photon sensitive Geiger-mode Avalanche Photodiode (GmAPD) array of detectors, dual green lasers with sub-nanosecond pulsewidth, and real-time Field-programmable Gate Array (FPGA) processing. Progress on the brassboard design and build, scheduled for field testing next year, will be presented.