Noeker, Matthias ; Van Ransbeeck, Emiel ; Ritter, Birgit ; Karatekin, Özgür

published in Aerospace Mechanisms Symposium, 46th, pp. 159-172 (2022)

Abstract: The ESA Hera mission will follow the NASA DART mission to the binary asteroid system Didymos for detailed investigation of the asteroids and the impact crater caused by the DART spacecraft. The Hera spacecraft will release two CubeSats, Milani and Juventas. In the final mission phase, Juventas will at-tempt landing on the secondary, Dimorphos. Here, the GRAvimeter for small Solar System bodies (GRASS) will measure the surface gravity. In this work, we describe the design, fabrication and testing of the gravimeter rotation mechanism with its key components. Overall, a gear-motor rotates the sensor head by means of gear train and continuous electrical contact is ensured by a slip ring. The main design drivers were the harsh deep-space environment, especially the cold operating temperature limit of −30 °C, and the limited mass (0.38 kg) and volume (1 CubeSat unit U = (100mm)³) budgets available inside the 6U-XL-CubeSat. While here the presented mechanism is specific to the GRASS scientific payload, it could be used for other future instrument demanding sensor head rotation or pointing.

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