Controlled Partial Gravity Platform for Milligravity in Drop Tower Experiments

We detail a platform for partial g environment and an experiment for simulated impacts on asteroid surfaces based on it. The partial g environment is created by a two stage approach: First, create microgravity using the ZARM drop tower. Second, convert microgravity to partial gravity by steady acceleration of experiment volume on linear drive inside microgravity environment. The experiment we conducted on this platform simulates low-velocity impacts into a simulated asteroid surface. To recreate the asteroid environment, in addition to the partial gravity, a vacuum chamber is used. We explain requirements, setup and operation of partial gravity platform and experiment and discuss its performance. Finally, we are open for requests for external experiments which might benefit from our platform with $9.3\,$s of controlled partial gravity down to the mm/s$^2$ range with low g-jitter.