What happens to sunscreen, mayonnaise and medicines in space? New study reveals...

Most everyday products, from skincare lotions to pharmaceuticals, are made of soft matter, gels or glasses whose microscopic structures shift slowly over time. Their shelf life, stability, consistency, and effectiveness, all depend on how these internal structures evolve.

On Earth, gravity constantly pulls on these materials, shaping how they change. But that also makes something impossible, we can never truly know what these materials would do without gravity.

So researchers from Politecnico di Milano, Université de Montpellier, and CNRS decided to take the experiment off the planet.

The result is COLIS (Colloids in Space), a cutting-edge science facility now operating on the ISS under ESA’s “Colloids in Space” programme, supported by ASI and CNES.

Created through a 25-year scientific partnership between physicists Luca Cipelletti and Roberto Piazza, COLIS is the first dedicated platform for studying the long-term behaviour of soft and complex materials in microgravity.

What COLIS Can Do

The facility uses dynamic light scattering, speckle pattern analysis, correlation imaging, polarization fluctuation measurements, temperature-controlled stimulation, etc. to observe how materials - restructure, age, crystallize, respond to heat, and form new phases, all without gravity interfering.

According to Piazza, eliminating gravity reveals its hidden influence, “Gravity is a silent but decisive force,” he says. “Studying materials in microgravity helps us understand how they really change over time.”

Early results from COLIS already show that gravity affects soft matter far more than expected, shaping its internal structure in ways that continue for months or years. This could explain why products sometimes separate, lose effectiveness, degrade, or crystallize unexpectedly.

In space, scientists can finally see these processes happen naturally, without Earth’s constant pull masking the details.

COLIS arrived on the ISS aboard NASA’s Cygnus NG-21 cargo craft and is already analyzing nanoparticle-based samples to track how they reorganize in microgravity.

For scientists like Cipelletti and Piazza, this is the culmination of decades of work. “Bringing soft matter physics to the ISS opens new frontiers,” says Cipelletti. “It helps us design better materials, and improves quality of life on Earth.”