NASA tests – NASA is testing an in-orbit refueling “cryocoupler” developed by L3Harris, built to automatically connect and disconnect spacecraft while transferring cryogenic propellants like liquid hydrogen and liquid oxygen without leaking. Engineers are running cold-flow
A future deep-space mission could hinge on something that sounds almost mundane: the ability to refuel without leaving orbit.
NASA is now testing a technology meant to make that possible—a “cryocoupler” developed by L3Harris designed to transfer extremely cold fluids between spacecraft before they push farther away from Earth.
NASA’s cryocoupler is being built for in-orbit cryogenic refueling. a step the agency says has never been done in the real way that matters for flight. Travis Belcher. cryocoupler project manager at NASA’s Marshall Space Flight Center in Huntsville. Alabama. put it plainly: “In-orbit cryogenic refueling between two spacecraft has yet to be done and remains one of the toughest engineering challenges in spaceflight.”.
The concept is intentionally mechanical. The cryocoupler is described as the nozzle of a gas pump, sized to mate with the “fuel tank” on a spacecraft. Instead of one vehicle heading out alone, multiple spacecraft could connect to orbiting “gas stations” and refill while they’re still near Earth.
That’s also where the difficulty lives. The device has to handle propellants such as liquid hydrogen and liquid oxygen—cryogens that must stay chilled at hundreds of degrees below Fahrenheit. Belcher says effective cryocouplers must transfer these fluids “without leaking,” which means the right materials and strong seals are non-negotiable.
There’s another constraint: it can’t rely on human hands in the void. The cryocoupler is designed to connect and disconnect multiple times and to be fully automated. so astronauts wouldn’t need to do a spacewalk to transfer propellant. Belcher says: “The cryocouplers we’re working on can attach and detach multiple times and are fully automated. so astronauts won’t have to perform a spacewalk to transfer propellant.”.
In addition to automation, Belcher emphasizes durability and fit. The device is described as “rigorously designed to withstand space” and “sized for the expected tank designs.”
For the testing that’s underway. Belcher’s team at Marshall ran liquid nitrogen at negative 321 degrees Fahrenheit through connected and disconnected configurations. Those tests were meant to generate data on how the cryocoupler responds to significant temperature differences. The team also ran operational tests built around docking reality—simulations of misaligned dockings—because the coupler was designed to accommodate some degree of misalignment.
At this stage, the work is still early. Belcher says future tests will be tailored for specific missions, allowing the cryocoupler to be assessed against mission requirements instead of general performance.
NASA even shared a glimpse of the ongoing work through a video associated with the June 26. 2026 update from NASA Marshall. where engineers from NASA’s Marshall and L3Harris are testing technology described as vital for in-orbit refueling for the agency’s next generation of deep space exploration missions.
NASA L3Harris cryocoupler in-orbit refueling cryogenic propellants liquid hydrogen liquid oxygen Marshall Space Flight Center spaceflight testing