HERA Mission LIDAR Mechanical and Optical Design

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.

Analysis on the Isostatic Bipod Mounts for the HERA Mission LIDAR

“…The Planetary ALTimeter (PALT) mechanical design has been optimized on different aspects to meet the requirements established for the HERA mission. In [6][7][8], the HELENA LIDAR's performance was evaluated regarding weaker requirement of shock, static simulation of 5G in two different directions, and thermal conductive simulations between −40 C. The main objective was to study the secondary mirror deformation towards the base of the telescope, and maximum stresses. Two different materials (aluminum and titanium) were assessed for the upper part of the LIDAR telescope.…”

Breadboard of Microchip Laser and Avalanche Photodiode in Geiger and Linear Mode for LiDAR Applications

“…In addition to performance requirements, payload design must also address limited spacecraft resources, such as power and total mass. In this context, the design of a space instrument, such as a LiDAR (Light Detection and Ranging) [1][2][3][4][5], entails specific experimental research.…”

Breadboard of Microchip and Avalanche Photodiode in Linear and Geiger Mode for LiDAR Applications

“…The selection of the payloads besides taking in consideration instrument performance also considers the spacecraft available resources (i.e., power consumption and mass of the instruments). For landing missions or spacecraft autonomous navigation near asteroids, to avoid collisions and assist operations, a LiDAR is important [1][2][3][4][5]. A LiDAR is an electromagnetic radiation-based instrument that can use time of flight technic [1][2][3][4][5].…”

“…For landing missions or spacecraft autonomous navigation near asteroids, to avoid collisions and assist operations, a LiDAR is important [1][2][3][4][5]. A LiDAR is an electromagnetic radiation-based instrument that can use time of flight technic [1][2][3][4][5]. The emitted photons, i.e., laser pulse, travel from the instrument to the object surface e.g., landing target and the back reflected photons, are received by the instrument's detector.…”