Laplace: glimpse into planet formation in microgravity

During star formation, a collapsing cloud of gas and dust flattens into a rotating protoplanetary disk around a young star. Within this disk, tiny dust grains collide and gradually grow into larger aggregates. Over time, these structures evolve into planetesimals and eventually planets. While this process is well established in theory, many of its early stages remain poorly understood.

Understanding dust growth in protoplanetary disks

Laplace focuses on the initial growth phase of planet formation, when micron‑sized dust grains collide at very low speeds and stick together to form loose, porous aggregates. These gentle collisions are difficult to study on Earth, where gravity compresses particles and alters their behaviour.

To faithfully reproduce the conditions inside a protoplanetary disk, Laplace studies dust clouds suspended in a thin gas atmosphere under microgravity. This environment prevents sedimentation and compression, allowing researchers to observe how particles move, interact, and grow purely through low energy collisions. Because these processes are slow, they require continuous microgravity over extended periods, making the International Space Station (ISS) the ideal platform.

The Laplace experiment setup

At the heart of the experiment is a thermophoretic trap, which uses a controlled temperature gradient to capture and hold microscopic dust particles within the gas. Once trapped, the particles remain freely mobile and can collide naturally. A dedicated camera system continuously records their motion and the formation of larger aggregates.

Dust particles are injected into the chamber, guided into the trap, and observed over time. The resulting image data are then transmitted to Earth for detailed analysis, enabling precise measurement of growth rates, particle size distributions, and collision behaviour.

Why microgravity matters

On Earth, gravity dominates particle dynamics and masks the subtle physical processes governing dust growth. In microgravity, researchers can isolate the key mechanisms driving aggregation, providing critical input for models of protoplanetary disk evolution. These insights can be directly compared with astronomical observations and used to refine theories of how planets form in young solar systems.

From dust to planets

By revealing how microscopic dust grains begin their journey toward forming planets, Laplace addresses one of the most persistent questions in planetary science. Its results will help bridge the gap between theory, laboratory experiments, and astronomical observations, bringing us closer to understanding how planetary systems like our own come into being.

International collaboration and mission status

The Laplace experiment is developed by an international consortium led by TU Braunschweig, with partners from the Free University of Brussels and the University of Central Florida. The project is funded by the German Space Agency at DLR (Deutsches Zentrum für Luft- und Raumfahrt; German Aerospace Center), with hardware development carried out by Space Applications Services NV/SA and TU Braunschweig on behalf of the German Space Agency at DLR. Read more about it here.

The experiment is scheduled to be launched to the International Space Station on the CRS SpX-34 mission (May 2026), where it will be accommodated inside the ICE Cubes Facility. Laplace will occupy the full volume of the facility as a large insert‑type payload and is expected to operate for approximately eight months. Throughout its mission, the experiment will be remotely monitored and operated from the ground, taking advantage of the ICE Cubes platform’s real‑time connectivity to enable continuous commanding and data access without direct crew interaction.