NASA RROxiTT: Testing new technologies for robotic refueling - Video

In space, a robot servicer could use propellant transfer technologies to extend the life of orbiting satellites (depicted, artist’s concept). 

Credit: NASA 

It's corrosive, it's hazardous, and it can cause an explosion powerful enough to thrust a satellite forward in space.

Multiple NASA centers are currently conducting a remotely controlled test of new technologies that would empower future space robots to transfer this dangerous fluid—satellite oxidizer—into the propellant tanks of spacecraft in space today.

Building on the success of the International Space Station's landmark Robotic Refueling Mission (RRM) demonstration, the ground-based Remote Robotic Oxidizer Transfer Test (RROxiTT) is taking another step forward in NASA's ongoing campaign to develop satellite-servicing capabilities for space architectures and human exploration.

August 2013 - In its second phase, RRM is now moving on to demonstrate how a space robot can complete intermediate tasks required to replenish croygen in the instruments of "legacy" satellites: existing, orbiting spacecraft that were not designed to be serviced. 

Initial activities to demonstrate this on-orbit capability were completed in March and June 2012 with the aid of the original RRM tools and activity boards.

Credit: NASA

On Earth, RROxiTT technologies could one day be applied to robotically replenish satellites before they launch, keeping humans at a safe distance during an extremely hazardous operation.

In space, a robot servicer could use propellant transfer technologies to extend the life of orbiting satellites (depicted, artist's concept).

Building on the Past to Set the Stage for the Future
In January 2013, RRM demonstrated that remotely controlled robots—using current-day technology—could work through the caps and wires on a satellite fuel valve and transfer fluid into existent, orbiting spacecraft that were not designed to be serviced.

To meet the safety requirements of space station, ethanol was used as a stand-in for satellite fuel.

For the team that conceived and built RRM, the Satellite Servicing Capabilities Office (SSCO) at NASA's Goddard Space Flight Center in Greenbelt, Md., the successful conclusion of this refueling demonstration was not the end of their work, only the beginning.

Benjamin Reed

"We were immensely pleased with RRM results. But doing more was always part of the plan," says Benjamin Reed, deputy project manager of SSCO.

"There were certain aspects of satellite refueling that couldn't be demonstrated safely while we were using space station as a test bed – aspects that we chose to defer to a later test date."

"RROxiTT is the next step in that technology development."


In this video, robotic arm operator Alex Janas introduces RROxiTT (Remote Robotic Oxidizer Transfer Test) while standing next to the robotic arm. 

Credit: NASA/GSFC/Scientific Visualization Studio

Taking lessons learned from RRM, the SSCO team devised the ground-based RROxiTT to test how robots can transfer oxidizer, at flight-like pressures and flow rates, through the propellant valve and into the mock tank of a satellite that was not designed to be serviced in space.

"No one has ever attempted this type of oxidizer transfer before," says Marion Riley, the SSCO test manager for RROxiTT.

"Like any NASA-sized challenge, we had to figure out—and at times, create—the right set of technologies and procedures to get the job done. Testing on the ground helps us know we're on the right track."

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Robotic Refueling: The Jumpstart Push Beyond LEO

On July 12, 2011, spacewalking astronauts Mike Fossum and Ron Garan successfully transferred the Robotic Refueling Mission, or RRM, module from the Atlantis shuttle cargo bay to a temporary platform on the International Space Station's Dextre robot.

Credit: NASA

In mid-January, NASA will take the next step in advancing robotic satellite-servicing technologies as it tests the Robotic Refueling Mission (RRM) aboard the International Space Station.

The investigation may one day substantially impact the many satellites that deliver products Americans rely upon daily, such as weather reports, cell phones and television news.

During five days of operations, controllers from NASA and the Canadian Space Agency will use the space station's remotely operated Special Purpose Dexterous Manipulator (Dextre), robot to simulate robotic refueling in space.

Operating a space-based robotic arm from the ground is a feat on its own, but NASA will do more than just robotics work as controllers remotely snip wires, unscrew caps and transfer simulated fuel.

The team also will demonstrate tools, technologies and techniques that could one day make satellites in space greener, more robust and more capable of delivering essential services to people on Earth.

Fix or Refuel a Satellite?

"Every satellite has a lifespan and eventual retirement date, determined by the reliability of its components and how much fuel it can carry," explains Benjamin Reed, deputy project manager of NASA's Satellite Servicing Capabilities Office (SSCO).

Repairing and refueling satellites already in place, Reed asserts, can be far less expensive than building and launching entirely new spacecraft, potentially saving millions, even billions of dollars and many years of work.

The RRM demonstration specifically tests what it would take to repair and refuel satellites traveling the busy space highway of geosynchronous Earth orbit, or GEO.

Located about 22,000 miles above Earth, this orbital path is home to more than 400 satellites, many of which beam communications, television and weather data to customers worldwide.

By developing robotic capabilities to repair and refuel GEO satellites, NASA hopes to add precious years of functional life to satellites and expand options for operators who face unexpected emergencies, tougher economic demands and aging fleets.

NASA also hopes that these new technologies will help boost the commercial satellite-servicing industry that is rapidly gaining momentum.