NASA's Satellite Refueling Mission Progresses with Help from DSTI Rotary Unions

DSTI - Dynamic Sealing Technologies, Inc.

Since the initiation of the Robotic Refueling Mission (RRM) in 2009, NASA's team has been working hard developing the right set of tools and technologies that would extend satellites' lifespans, thus saving money while reducing orbital debris.

More than 1,000 operational satellites currently in orbit will one day run out of fuel and burn up in our atmosphere as they fall back towards Earth or remain space debris forever. Costing tens of millions of dollars each launch, satellites have a limited lifespan restricted by their fuel tank capacity. However, with DSTI's help and NASA's continued research, servicing and refueling missions may become a realistic option to drastically extend their life.


Since the initiation of the Robotic Refueling Mission (RRM) in 2009, NASA's team has been working hard developing the right set of tools and technologies that would extend satellites' lifespans. Three RRM operational phases were executed to demonstrate a set of satellite servicing and refueling tasks. During phases one and three, specialized rotary unions were required to reliably transfer cryogenic fluid from a source tank through a sophisticated robotic fueling hose to a receiver tank.


DSTI's sales and engineering teams worked directly with NASA engineers to develop a custom-engineered rotary union solution for the RRM's first phase. During testing the union was subjected to the same vacuum and temperature extremes (as low as -310°F) that it encountered during its mission. In 2013, mission controllers successfully performed phase one, a first-of-its-kind demonstration of transferring a simulated fuel in space.

In preparation for the third and final RRM phase (scheduled to launch to the International Space Station in 2018), revisions to the rotary union design were required. DSTI engineers developed a revised, space-ready rotary union based off lessons-learned, equipment refinements, and test results from earlier prototypes.


DSTI provided NASA with two custom rotary union designs for RRM phase one and three. The first union performed very well in all tests and during the 2013 RRM mission. "We were thrilled with the performance during testing of DSTI's early rotary union prototype units for RRM. Even under pressure, they ran with almost zero parasitic torque," says Matt Ashmore, Mechanical Engineer for NASA/Orbital ATK's Satellite Servicing Projects Division.

All of this work is leading up to the 2020 Restore-L mission, an endeavor to launch a robotic spacecraft to refuel a live satellite. Successful completion of the mission will demonstrate that servicing and refueling technologies are ready for incorporation into other NASA missions as well as allowing commercial entities to help jump-start a new domestic servicing industry.


- Specialized sealing material and surface finishes suitable for transferring cryogenic fluid

- Allows refueling hose to freely rotate during robotic positioning

- Open communication and transparency throughout the process contributing to mission success

- All required documentation delivered upon shipment

DSTI's Custom Rotary Union for Space
DSTI's Custom Rotary Union for Space

Single passage rotary union designed for a cryogenic (liquid methane) hose deployment system for satellite refueling in near and distant orbit. Features include a compact lightweight, low-torque design. Fully tested sealing system designed to handle media temperatures between -310F to -256F.

Satellite Refueling