Condensation alien

Greyscale footage shows how vapour condenses on the ground (left) and on the International Space Station (right). The footage is sped up five times – the whole clip took around one minute in real time.

On Earth the liquid accumulates at the foot of the fin, whereas in microgravity the liquid spreads across the entire surface as a thin film.

The black layer on the surface of the fin shows the thickness of the moisture layer. On Earth, the liquid film is very thin. In space, without gravity’s pull, this film becomes thicker.

For the first time, a European experiment is looking at the shape liquid films take on cooled surfaces aboard the International Space Station. A fin-shaped metal is in the spotlight for scientists to better observe condensation, liquid drainage and vapour convection.

The Condensation on Fins experiment is pioneering heat transfer tests in orbit to study the role of capillary pressure – the force that pulls liquids through tiny spaces, like water climbing up a paper towel – and condensation, all without gravity getting in the way.