Update on the Laplace experiment as a facility to investigate the initial stage of planet formation

The predecessor of Laplace, ICAPS, was flown in 2019 and 2023 on the Texus-56 and Texus-58 sounding rockets. The Laplace facility is planned for a usage on the ISS with a launch in 2025. Both experiments allow to investigate the very first stages of planet formation. The relevant growth processes require observation of many-particle processes consisting of millions of µm-sized particles in a low-density gas environment (typically a few 10s of Pa, such that Knudsen numbers of >>1 are achieved) for prolonged time. The latter requirement makes it necessary to perform these investigations in a microgravity environment. The ICAPS and Laplace setups allow to actively protect the dust cloud against diffusion and other external residual forces and also allow concentration of the dust cloud by means of an actively-controlled thermophoretic trap acting on all three axes.

Simultaneously, the dust cloud is made available to a number of observational instruments. As a whole, the cloud is observed in 3D from two perpendicular overview cameras while also making a small central volume of 1 mm² cross-section accessible to a dedicated long-distance microscope with high-speed imaging to facilitate non-destructive in-situ analysis of the growing dust aggregates. An extinction sensor allows to measure the light extinction throughout the cloud as a whole. Measurements of the electric charges of the individual particles can be conducted repeatedly by means of a controlled DC or AC field in order to determine charge and charge evolution.

We will present the design and techniques of the Laplace setup, the current status of the Laplace facility and demonstrate its capabilities on a few select data from the flights of ICAPS.