The MASCOT lander aboard Hayabusa2: The in-situ exploration of NEA (162173) Ryugu

Abstract After 3.5 years of cruise, and about 3 months in the vicinity of its target, the MASCOT lander was deployed successfully on 3rd October 2018 by the Hayabusa2 spacecraft onto the C-type near-Earth asteroid (162173) Ryugu. After a free-fall of 5 min 51 sec from an altitude of 41 m MASCOT experienced its first contact with the asteroid hitting a big boulder. The lander bounced for ∼ 11 min 3 sec before it came to rest. MASCOT was able to perform science measurements with its payload suite at 3 different locations on the surface of Ryugu. It investigated the fine-scale structure, multispectral reflectance, thermal characteristics and magnetic properties. The surface consists of very rugged terrain littered with large surface boulders. The in-situ measurements confirmed the absence of fine particles and dust as already implied by the remote sensing instruments aboard the Hayabusa2 spacecraft. After about 17 hours of operations, the MASCOT mission terminated with the last communication contact as its primary batteries depleted. This paper summarizes the MASCOT mission covering its four years of in-flight operations, its preparation for the descent, landing and in-situ investigation on the asteroid Ryugu until the end of its operation.