Your sunscreen sits in the bathroom cabinet, slowly changing. The mayonnaise in your fridge gradually separates. That prescription cream loses effectiveness over time. All these materials share something fundamental, they're soft matter, substances like gels, foams, and colloids whose internal structure reorganises slowly and mysteriously over months or years.

Understanding exactly what happens inside these materials as they age has always been complicated by gravity. Even sitting still on a shelf, Earth's gravitational pull constantly influences how particles within these substances settle, cluster, and rearrange themselves. So a team of researchers from Politecnico di Milano and the Université de Montpellier decided to study soft matter somewhere gravity that gravity will have no effect.

The result is COLIS, a new experimental facility now operating aboard the International Space Station. The laboratory represents the culmination of more than 25 years of collaboration between Luca Cipelletti, a physicist at the Laboratoire Charles Coulomb, and Roberto Piazza, who runs the Soft Matter laboratory at Politecnico di Milano.

COLIS uses sophisticated optical techniques to look inside materials without disturbing them. Dynamic light scattering analyses how laser beams pass through samples, revealing tiny variations called speckle patterns that show how gels and other soft materials restructure over time. The facility can also carefully heat samples to trigger aging processes in precise, reproducible ways, then watch what happens at the molecular level.

Early results have already surprised the research team. Gravity affects soft matter structure more dramatically than expected, influencing material properties even over long timescales.