NASA makes a significant investment in on-orbit spacecraft refueling

By Eric Berger

If one wants to have Starships on Mars, one first has to refuel them in Earth orbit.
Enlarge / If one wants to have Starships on Mars, one first has to refuel them in Earth orbit.

NASA has reached an agreement with 14 US companies to develop technologies that will enable future modes of exploration in space and on the surface of the Moon. NASA says the value of these awards for "Tipping Point" technologies is more than $370 million.

With these awards, the space agency is leaning heavily into technologies related to the collection, storage, and transfer of cryogenic propellants in space. Four of the awards, totaling more than $250 million, will go to companies specifically for "cryogenic fluid management" tech demonstrations:

  • Eta Space of Merritt Island, Florida, $27 million. Small-scale flight demonstration of a complete cryogenic oxygen fluid management system. System will be the primary payload on a Rocket Lab Photon satellite and collect critical cryogenic fluid management data in orbit for nine months.
  • Lockheed Martin of Littleton, Colorado, $89.7 million. In-space demonstration mission using liquid hydrogen to test more than a dozen cryogenic fluid management technologies, positioning them for infusion into future space systems.
  • SpaceX of Hawthorne, California, $53.2 million. Large-scale flight demonstration to transfer 10 metric tons of cryogenic propellant, specifically liquid oxygen, between tanks on a Starship vehicle.
  • United Launch Alliance (ULA) of Centennial, Colorado, $86.2 million. Demonstration of a smart propulsion cryogenic system, using liquid oxygen and hydrogen, on a Vulcan Centaur upper stage. The system will test precise tank-pressure control, tank-to-tank transfer, and multiweek propellant storage.

These awards are notable because, for much of the last decade, the agency has been hesitant to invest in technologies that will enable the handling of cold propellant in space. The official reason given for this reluctance has been that the technology of creating propellant "depots," and transferring liquid hydrogen and oxygen to and from these depots, was deemed not ready for prime time. But there were political reasons as well.

The reality is that creating in-space fueling technologies enables a new paradigm for spaceflight. It allows for the refueling of a rocket's second stage for multiple uses, enables reusable "tugs" that can move back and forth between the Earth and Moon, and allows smaller rockets to play a larger role in exploration programs. All of this undermines the need for a very large, expensive rocket like the Space Launch System that Congress directed NASA to build.

Of the four new awards, the two most notable are the ones going to United Launch Alliance (ULA) and SpaceX. ULA has been interested in cryo-storage technology for years, having done some research on its own about a decade ago, and was preparing for in-space tests on propellent depots. Then, in 2011, one of ULA's co-owners, Boeing, won a contract to build the core stage of the Space Launch System rocket. Internal work on this depot technology largely stopped.