NASA Tests Space Refueling Technology for Moon and Mars Missions

Breaking the Fuel Barrier

Picture trying to drive cross-country with no gas stations along the way. That's essentially the challenge NASA faces when sending astronauts to the Moon and Mars. A new NASA satellite will test critical technologies for storing and transferring super-chilled, cryogenic fuels in space in order to help astronauts reach the moon and potentially Mars someday. The Liquid Oxygen Flight demonstration (LOXSAT) will launch to orbit around the Earth later this year to test the fluid management capabilities that will be needed to maintain cryogenic fuels in microgravity, which come with additional challenges compared to other propellants.

In a statement, NASA said these in-space propellant depots could some day be "essentially gas stations in space that could support long-term exploration." LOXSAT is scheduled to launch this summer aboard a Rocket Lab Photon satellite, riding an Electron launch vehicle from New Zealand no earlier than July 17. The mission, planned to last nine months, will rigorously test 11 different components designed to manage super-chilled propellants in low Earth orbit.

The Cryogenic Challenge

Cryogenic fuels, such as liquid oxygen, liquid hydrogen, and methane, require extremely low temperatures to remain liquid, and transferring them between spacecraft in microgravity poses significant engineering challenges. Reports suggest the company is struggling to mitigate the effects of "boiloff", where cryogenic propellants sublimate (turn directly into a gas from their frozen state) due to constant temperature fluctuations. As boiloff occurs, pressure builds, and Starship must vent gas and lose propellant to prevent damage.

According to a NASA statement, LOXSAT will demonstrate technologies that "were selected to address the core challenges of using cryogenic, or super-cold, propellants in microgravity, including reducing boiloff, transferring propellant, maintaining tank pressure, and gauging propellant levels." This includes systems for lossless storage of liquid oxygen, pressure control in microgravity, coupling and decoupling of connections, and, crucially, the transfer of propellants between vehicles, a capability that no spacecraft has demonstrated in practice to date.

Game-Changing Economics

The idea is simple in theory and revolutionary in practice: instead of launching a spacecraft from Earth carrying all the fuel needed for the entire journey, the spacecraft would take off lighter and fill up at an orbital station before heading to the final destination. This drastically reduces the weight at launch, and weight is the factor that most increases the cost of any space mission. Effective in-space fueling could allow spacecraft to carry smaller initial fuel loads, reduce launch costs, and increase flexibility for mission planning.

Both Artemis lunar landers commissioned under NASA's Human Landing System contracts rely on cryogenic propellants, and require on-orbit refueling in order to complete their missions of landing astronauts on the lunar surface and delivering them back to lunar orbit. Both of the lunar landers selected by NASA to carry astronauts to the Moon's surface — SpaceX's Starship and Blue Origin's Blue Moon — rely heavily on these temperamental fuels. Starship burns a mix of liquid oxygen and liquid methane, while Blue Moon uses liquid oxygen and liquid hydrogen.

Racing to the Future

The Artemis 3 mission, which is expected to launch four astronauts to the Moon at the end of 2027, directly depends on these technologies. When Artemis 3 happens, LOXSAT will have already completed its nine months of orbital demonstrations, and the data collected could inform SpaceX and Blue Origin's efforts to enable cryogenic refueling in microgravity. China has already reportedly demonstrated on-orbit refueling technologies in space with its Shijian 21 and 25 satellites.

The ability to refuel in orbit represents a transformational step toward sustainable deep space exploration. If LOXSAT successfully demonstrates the technology, it could serve as a blueprint for establishing orbital propellant depots that supply spacecraft heading to the moon and Mars. This summer's mission could mark the beginning of a new era where space travel becomes as routine as stopping at your neighborhood gas station.