ESA astronaut Thomas Pesquet using the International Space Station's freezers during his six-month Proxima mission in 2017.
Thomas wrote: "Happy birthday, MELFI! This fridge has been keeping things cool on the International Space Station for 10 years now. It was made by Air Liquide for ESA and we use it to store all manner of things but mainly biological samples for researchers to analyse on Earth. Think, blood, saliva, urine and more... We actually have three MELFIs onboard, one in the US Destiny lab and two in the Japanese Kibo. They are critical for the majority of our human and biology research experiments. Without MELFI we would have a hard time doing any human research at all. Ground control tracks how full the freezers are and anxiously waits for a return cargo vehicle to bring down all these precious samples. The MELFIs are pretty full right now since we have not had a SpaceX cargo ship arrive for a while (HTV and Cygnus do not land but on Earth but burn up on reentry, so we load them only with trash). It uses nitrogen to cool. Depending on the week's experiments we use it on a daily basis. Its full name is "Minus Eighty-degree Laboratory Freezer for ISS" so it includes an acronym in an acronym, did I tell you already that space engineers love acronyms?"
Connect with Thomas at http://thomaspesquet.esa.int