Multi-purpose laser communication system for the asteroid impact mission (AIM)

By the end of 2022 the binary Asteroid Didymos will pass the Earth at a distance of 15 Mio km at its closest approach. Didymos consists of a larger body (Didymain) and a small companion (Didymoon). ESA, together with NASA, DLR, APL and the Observatoire de la Cote d'Azur, are studying a mission called AIDA to test our ability to perform a spacecraft impact on a potentially hazardous near-Earth asteroid and to measure and characterize the deflection caused by the impact. In particular, ESA is preparing a mission to be launched by end of 2020 to study Didymoon's properties necessary to fully characterize the impact, also by means of a micro-lander on its surface. NASA intends to contribute with DART, a small impactor spacecraft, and to measure the deflection from ground by monitoring the binarýs orbital period change through light-curves. Measurements of scientific and technical parameters are intended to be performed allowing to interpret the deflection and extrapolate results to future missions or other asteroid targets. The AIM spacecraft will carry a multi-purpose laser communication terminal which will utilize individual components of the laser communication system to additionally perform imaging of the asteroid (at thermal infrared wavelengths) and to measure the Asteroid's surface topography using a pseudo random modulation LIDAR. The laser communication system will utilize technologies and components that have been developed by European industry over the last decade and from recent communication equipment developments for the Lunar Atmospheric and Dust Environmental Explorer (LADEE) performed in 2013/14 in collaboration with NASA. The link distance that need to be covered will range from 0.1 AU to 0.5 AU (15 Mio km to 75 Mio km).