Briefs: Cryocooling in outer space

MELFI (Minus Eighty degrees Celsius Laboratory Freezer) has been developed for the International Space Station (ISS) under a European Space Agency (ESA) contract for NASA. It is used to preserve biological and scientific samples until they return to Earth. According to a presentation given by J. Cheganças at ICR2007, the Brayton technology used has been very critical to develop but has finally proved to be very efficient in orbit; it provides 4 storage volumes for all biological samples requiring temperatures from ambient to -97°C. The freezer was developed by Air Liquide for the ESA. Since July 2006, when it began service on board the ISS, MELFI has operated over 8000 hours without any incidents. For this reason, NASA decided to extend its period in orbit by 5 years. The photo shows the MELFI Brayton machine