NASA Armstrong is Working on a Sensor Technology that will Convert Oxygen into Fuel

By Sophia Francise

August 1, 2023

NASA is aiming to establish a sustainable presence on the Moon and place humans on Mars by using natural resources for rocket fuel to refill landers on both surfaces.

The success of this technology means future astronauts could top off fuel after landing on the Moon, enabling lighter and cheaper lunar landers without the need for fuel haulage during the return journey from Earth.

To enable this, NASA’s Armstrong Flight Research Center in Edwards, California, has been developing the Fiber Optic Sensing System (FOSS) technology.

The system took temperature readings during tests of a system designed to liquefy oxygen in the same way it will be done on the lunar surface. 

During the tests at NASA’s Glenn Research Center in Cleveland, FOSS tracked the temperatures inside a cylinder as oxygen froze and condensed from gas to liquid at minus 297 degrees Fahrenheit.

The Fiber Optic Sensing System Explained

FOSS collects thousands of measurements of temperature, strain, and other data essential to mission safety using long strands of fiber optic cable roughly the thickness of a human hair. 

In the past, gathering and delivering this data required large wires and sensors. 

The FOSS team at NASA Armstrong is modifying the technology, originally created for aviation, for use in space missions.

The development of this space-specific technology was initiated in 2018 by NASA Armstrong researchers.

Known as the FOSS system for CryoFILL, Cryogenic Fluid In-situ Liquefaction for Landers, they aimed to create a liquid oxygen manufacturing system.

“We’ve been using fiber for temperature measurement but not in the realm of liquid oxygen testing. We had to develop a unique sensor suitable for these extremely cold temperatures,” said Patrick Chan, electronics engineer, and NASA Armstrong’s FOSS portfolio project manager.

The FOSS team developed a strong, nonflammable synthetic material to protect the fiber from cold and ensure safety in pure oxygen atmospheres.[1]

They tested FOSS sensors using liquid nitrogen before shipping them to NASA Glenn for testing. 

The CryoFILL testing setup used a 77-inch tank with a storage capacity of up to 528 gallons, a 140-inch FOSS strand with 330 sensors, and a second temperature measuring system with silicon diodes.

Over 40 liquefaction tests, ranging from 24 to over 200 hours, were conducted over several months, examining flow and tank pressurization rates.


Chan expressed awe for the functionality of the FOSS system. Additional optic fibers will be put into the liquid oxygen-producing tank to provide further data if the CryoFILL project continues with further testing.

CryoFILL is a component of the NASA Space Technology Mission Directorate’s Cryogenic Fluid Management Portfolio Project, which falls under the program for technology demonstration missions.


  1. NASA, ‘NASA Armstrong Sensor Technology Helping Turn Oxygen into Fuel’, 31 July 2023,[]