How a space turbo-machine paved the way for Turbo-Brayton

For two decades, MELFI (Minus Eighty-Degree Laboratory Freezer for ISS), the "super-freezer" to which Air Liquide contributed, has operated continuously aboard the International Space Station. Originally designed for just two to three years of service, this 800-kg cryogenic engineering marvel has now delivered 20 years of flawless reliability in orbit, and its underlying Turbo-Brayton technology today cools liquefied natural gas (LNG) carrier vessels across the globe and superconducting cables.

An engineering challenge: preserving science in the extreme conditions of space

MELFI was created to solve a critical scientific need: preserving delicate biological and scientific samples—including blood, saliva, and experimental tissues—at cryogenic temperatures down to -95°C before their return to Earth for analysis. To do so, MELFI needed a reliable cooling system, developed by Air Liquide’s advanced Technologies teams on the Campus Technologies Grenoble for the European Space Agency (ESA) and NASA. 

To achieve extreme cold in microgravity, Air Liquide engineers equipped MELFI with high-performance turbomachines based on proprietary Turbo-Brayton technology. Unlike standard refrigeration systems, these turbomachines were engineered to withstand the harsh environment of orbit while operating with zero vibration to protect microgravity experiments.

Unmatched reliability: from a 3-year mission to 20 years of flawless service

When MELFI first launched, Air Liquide committed to an initial operational life expectancy of three years. Today, 20 years later, the unit continues to support international scientific research without a single failure.

• Hundreds of thousands of operating hours: Across the three turbo-machines placed in orbit (launched in 2006, 2009, and 2010), well over 465,000 hours of continuous, trouble-free operation have been accumulated.
• A symbol of cryogenic excellence: The endurance of MELFI’s turbomachines stands as one of the space industry’s most compelling demonstrations of cryogenic equipment longevity, proving that Air Liquide's engineering can withstand the test of decades in space.

From orbit to Earth: paving the way for today's Turbo-Brayton best-seller

The most enduring legacy of MELFI's 20-year milestone is how space innovation directly drove terrestrial industrial success.

The exceptional reliability demonstrated by the Turbo-Brayton turbomachines aboard the ISS served as the ultimate proving ground. Air Liquide scaled and adapted this very same Turbo-Brayton refrigeration technology for large-scale maritime and industrial applications on Earth. Today, Turbo-Brayton is Air Liquide’s best-selling cryogenic solution for re-liquefying boil-off gas on Liquefied Natural Gas (LNG) carrier vessels—preventing greenhouse gas emissions and preserving energy during maritime transport, as well as superconducting cables on earth.

* Photo Credits: ESA/NASA