ESA astronaut Sophie Adenot holds a cartridge filled with a white emulsion of oil and water. A couple of weeks into the εpsilon mission, she replaced samples for an experiment dedicated to studying how fluids behave in microgravity in a corner of Europe’s Columbus laboratory.

This experiment, called SMD-SEEDS/PASTA, investigates droplet dynamics to pave the way for more sustainable emulsions on Earth. Scientists closely observe the mixtures as they evolve through different stages, building on nearly two decades of European research on the International Space Station.

That research revealed that it is possible to create super-stable emulsions in orbit. From vinaigrette to mayonnaise, emulsions are part of our daily lives, yet gravity makes them short-lived on Earth, where emulsions break down in a frenzy compared to the more stable conditions on the station. Gravity splits the fluids by density, triggering effects like creaming and sedimentation. Think of your frothy cappuccino.

At Sophie’s new home in space, different concentrations of oil, air and foaming agents produce a range of emulsions. Inside each sample unit, pistons shake the liquids at high speed to generate droplets.

Scientists follow their evolution over several days using laser optics, fast detectors, and high-resolution cameras. The results are then sent to the Belgian User Operations Centre in Brussels, Belgium, where operators control the experiment remotely.

This sample replacement is most likely to be the last one for the Soft Matter Dynamics instrument. During previous missions the instrument has studied foams, granular materials and a variety of emulsions part of our everyday lives.

A deeper understanding of how these materials behave could unlock more sustainable ways to produce them, with benefits both on Earth and for human space exploration.

Follow Sophie’s mission on the εpsilon page and on her social media platforms, including X,Facebook, Instagram and LinkedIn.