The ESA Hera Mission: Investigating binary asteroid (65803) Didymos and the DART crater

IntroductionOn 26 September 2022 NASA's Double Asteroid Redirection Test (DART) spacecraft will impact Dimorphos, the satellite of asteroid (65803) Didymos. The impact will change Dimorphos' orbital period around Didymos. As Didymos is an eclipsing binary, and on a close flyby of Earth on this date, the period change can be detected by Earth-based observer