HERA Mission LIDAR Mechanical and Optical Design. Issue 1 (1st February 2022) - Dias, Nicole G.
Abstract: Near-Earth Objects (NEO) are the topic of several research studies, with objects smaller than 1km in size posing the most threats and being the less understood of this scientific domain. The Asteroid Impact and Deflection Assessment (AIDA) mission involves NASA and ESA with the main mission goal to perform and analyze the asteroid deflection using the Kinetic Impactor technique. The mission target is Didymos-B, a moon of a binary asteroid called Didymos. NASA oversees the Double Asteroid Redirection Test (DART probe), and ESA is responsible for HERA probe, that will measure the Dydimos-B deflection caused by the impact. The Light Detection and Ranging (LIDAR), the Radar, the Satellite-to-Satellite Doppler tracking, the Seismometer, and the Gravimeter are instruments integrated into HERA spacecraft. Information synergy between the instruments allows the detailed characterization of the asteroid including internal structure. This experiment allows further understanding and will provide important information to improve the current NEO understanding and modelling. In this paper, scientific advances related to the LIDAR instrument are reported, including the innovative optomechanical design resulting from thermal and mechanical optimizations. The LIDAR has a compact design and needs to withstand extreme conditions, such as radiative and thermal conditions, without compromise its high accuracy measurements. The LIDAR is a time-of-flight altimeter instrument that will measure the distances from the HERA spacecraft to the target. It provides information for a 3D topographic mapping and calculates the asteroid reflectivity. The measurements are to be performed at a distance from 500 m to 14 km while operations such as fly byes or landings remain a possibility.