The flame was sparked using a small drop of ethanol or heptane, a fuel, which then burns as a floating ball for up to 20 seconds.

It's all part of a series of experiments to observe how fire behaves in space and see if there are things this can show us that will be of use back on Earth, through the research of new liquid fuels.

The NASA Flame Extinguishment Experiment is designed to investigate the best way to put out a fire and what "fire suppressant" materials work better than others. One of the biggest threats to crews aboard the space station is open flames.

Fire burns at a lower temperature and with less oxygen in space.

Nasa says: "The most surprising discovery is the apparent continued 'burning' of heptane droplets after flame extinction under certain conditions, a unique observation with significant implications."