FILE - This May 23, 2010 image provided by NASA shows the International Space Station with the Earth in the background made from the space shuttle Atlantis after undocking. On Wednesday, Jan. 8, 2014, NASA said the White House was poised to announce an extension of the space station's lifetime until at least 2024. The previous end-of-life date was 2020. (AP Photo/NASA)
Astronauts on the International Space Station are playing with fire!
They're conducting experiments on how fuel burns in micro-gravity.
NASA astronaut Reid Wiseman tweeted out vines of the little fires on Thursday.
He wrote they look like "jellyfish on fire."
They're looking at how quickly fuel burns, the conditions needed for soot to form - and how mixtures of fuels evaporate before burning.
NASA says the experiments could lead to the development of safer spacecraft, and increased fuel efficiency back on earth.