Robotic Refueling Mission 3 Can’t Perform Cryogenic Fuel Transfer

Edward Cheung, an engineer at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, performs a fit check of RRM3’s three external tools. After RRM3 is installed to the outside of International Space Station the Dextre robotic arm will mount the pedestal and tools, pre-assembled by astronauts on the space station. (Credit: NASA/Goddard/Chris Gunn)

GREENBELT, Md. (NASA PR) — On April 8, the Robotic Refueling Mission 3 (RRM3) aboard the International Space Station started experiencing issues powering up its cryogen coolers that maintain the temperature of liquid methane contained within the module. After several troubleshooting attempts, it was determined the coolers could not be powered up. As a result, the temperature of the liquid began to rise. The liquid methane turned into a gas and was safely vented from the payload. There was no impact to other station systems or operations.

While RRM3 can no longer perform a cryogenic fuel transfer, its four months on station taught NASA about the technology needed to store and transfer cryogenic fuel in space. The mission will carry out other planned operations with servicing and inspection tools. Ultimately, RRM3 will still help bring NASA closer to replenishing cryogenic fuel in space so spacecraft can live longer and journey farther into the solar system.

RRM3 launched to the space station in December 2018 and is installed to the outside of station on Express Logistics Carrier-1.

  • Andrew_M_Swallow

    If NASA is going back to the Moon then it will have to prepare the high level design of its lander within the next couple of years. This means that the Goddard Space Flight Center has just over a year left to fix the problems with its refuelling hardware.

    A methane based lander needs to keep cool its methane, lox and helium propellants. A reusable lander will need all 3 refuelling on the Moon or in orbit (or both).

  • DP Huntsman

    A cryocooler that can’t even be successfully turned on at this stage is no small thing; yet there was no mention of a failure assessment team or timeline. Cryo storage and transfer of propellant is a critical technology going forward; the visibility of and reporting into this issue needs to be raised a level.
    Dave Huntsman

  • TheBrett

    That’s really unfortunate. We need the capability to store and transfer cryogenic propellant and oxidizer in orbit, and preferably long-term storage as well.