What the study found
Granular materials jam at a lower packing density in microgravity than on Earth. The study also found that, in microgravity, cohesive interparticle forces increase the stress needed for granular media to flow.
Why the authors say this matters
The authors say understanding granular behavior in low gravity is crucial for planetary science and space exploration. The study suggests that these results also help disentangle gravity’s role from intrinsic particle interactions and indicate the need for granular models that work in low- and microgravity environments.
What the researchers tested
The researchers carried out a series of compression and shear experiments in microgravity using the Center of Applied Space Technology and Microgravity drop tower and GraviTower Bremen. They used an in-house experimental setup to measure packing density and in situ shear stress with a Taylor–Couette rheometer, a device for measuring how materials flow under shear.
What worked and what didn't
The experiments showed that the jamming transition occurred at a lower packing density in microgravity than on Earth, which the authors describe as confirming that gravity promotes densification. Rheological measurements, which examine flow behavior, further showed that the lack of a secondary force field in microgravity and the dominance of cohesive forces increased the stress required for flow.
What to keep in mind
The abstract does not describe specific limitations of the experiments beyond the focus on microgravity and the comparison with Earth conditions. The findings are presented for the tested granular systems and the experimental setups described in the study.
Key points
- Granular materials jammed at a lower packing density in microgravity than on Earth.
- Cohesive interparticle forces increased the stress needed for granular media to flow in microgravity.
- The researchers performed compression and shear experiments using drop-tower microgravity facilities.
- A Taylor–Couette rheometer was used to measure in situ shear stress.
- The authors say the results support the need for granular models valid in low- and microgravity environments.
Disclosure
- Research title:
- Microgravity lowers the jamming point of granular materials
- Authors:
- Olfa D’Angelo, Qing Yu, Thorsten Pöschel
- Institutions:
- Friedrich-Alexander-Universität Erlangen-Nürnberg, National Higher French Institute of Aeronautics and Space, Technische Hochschule Ingolstadt, Technical University of Munich
- Publication date:
- 2026-04-21
- OpenAlex record:
- View
- Image credit:
- Photo by Mrs_MioraS on Pixabay · Pixabay License
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