Fueling up in Space: The Robotic Refueling Mission (RRM)
The Robotic Refueling Mission
The Canadian Space Agency (CSA) is collaborating with the NASA on the Robotic Refueling Mission (RRM), an experiment on the exterior of the International Space Station (ISS). RRM was designed to use Dextre, the Station's Canadian-built robotic handyman, to test the technologies, tools and techniques that could be used to service and refuel satellites in orbit, especially those not built to be refurbished. The mission marks the first time that Dextre is being used for a research and development project, and illustrates how the space station is increasingly being used as a technology test-bed.
Dextre, gas attendant: The Robotic Refueling Mission
The RRM, Dextre's most demanding task, resumes Monday on the ISS. In this video, the CSA's Mathieu Caron explains the next phase of RRM in which Dextre will simulate refueling a mock satellite with liquid ethanol. (Credit: CSA)
Dextre's first R&D experiment to test how robots could refuel satellites
For RRM, NASA's Goddard Space Flight Center designed a module and tool kit for Dextre. Launched on board the final flight of the space shuttle in 2011, the cube-shaped module is roughly the size of a washing machine (about 250 kg), and has 28 different pieces and parts found on a typical satellite: caps (similar to the gas cap on a car), nozzles, valves, and wires. The RRM module also has four new tools for Dextre housed inside: a Blanket Manipulation Tool, a Wire Cutter, Multifunction Tool, Safety Cap Removal Tool and Nozzle Tool. The tools (each about the size of a toaster) will allow Dextre to complete tasks like cutting through the simulated satellite's lock wires and blanket tape and removing layers of insulation.
An international effort for a global problem
On-orbit robotic servicing technologies hold great potential for addressing the issue of space debris, a growing concern for the world's space agencies. Both NASA and the CSA recognize the potential of test demonstrations like RRM to lay the foundation for future missions that might one day be able to send robots to repair, refuel and reposition orbiting satellites.
For RRM, the American and Canadian space agencies assembled an international project team with a vast and varied expertise. NASA's Goddard Space Flight Center has over 20 years of experience in servicing the Hubble Space Telescope, which was done with the iconic Canadarm. Canada brings to the table 30 years of experience with the shuttle's robotic arm, as well as more than a decade of operating Canadarm2 and now Dextre on board the space station. Tests to prepare for on-orbit RRM operations were conducted at Goddard and at MacDonald, Dettwiler and Associates Ltd. (MDA) in Brampton, Ontario (formerly SPAR Aerospace, the prime contractor for the Canadarm as well as the CSA's Mobile Servicing System on board the station). And RRM operations on board the space station are choreographed and coordinated by international ground crews at NASA's Goddard Space Flight Center in Greenbelt, Maryland; Johnson Space Center in Houston, Texas; Marshall Space Flight Center in Huntsville, Alabama; and the CSA's mission control center in Longueuil, Quebec.
In addition to the Canadian robotics on board the ISS and projects like RRM, the CSA is also looking ahead to advance state-of-the-of-art space robotics with the Next-Generation Canadarm project, a research and development initiative that is currently developing new robotic architectures, components, tools and techniques for future satellite servicing missions. The work being conducted by the CSA in on-orbit robotics servicing will not only position Canada for exploration missions to come, but will also open doors for commercial applications driven by industry.
The RRM tool box and customized task box are the size of a washing machine (mock-up shown here). The RRM hardware was launched into space on board flight STS-135, the last flight of the Space Shuttle. (Credit: NASA)
NASA astronaut, Mike Fossum, holds the hardware box for the RRM while Canadarm2 moves him towards Dextre's workbench. Once Mission STS-135 is complete, Canadarm2 and Dextre will install the RRM equipment on the EXPRESS Logistics Carrier 4 on the ISS. (Credit: NASA)
The hardware box for the RRM is being installed on Dextre's workbench (middle). The NASA astronaut wearing the space suit with the red stripes, Mike Fossum (left), is attached to Canadarm2, the ISS robotic arm. Ron Garan, in the white space suit (right), is moving closer to Fossum to help him secure the RRM equipment on one of Dextre's arms. (Credit: NASA)
Dextre received the tools and task box which will be used for its first research and development project, the RRM. (Credit: NASA)
Dextre (left) with the RRM module (centre). (Credit: NASA)
Perched on the end of Canadarm2, Dextre installs the RRM hardware on the ISS (the ExPRESS Logistics Carrier-4) on September 2, 2011. (Credit: NASA)
A close-up view taken by a low-resolution engineering camera of the black wire cutting tool used by Dextre (not visible) as it cuts the ambient cap wire on the RRM module in March 2012. This task was one of the mission's trickiest operations, with only about a millimetre of clearance. (Credit: NASA/CSA)
A close-up of the multi-function tool (left) held by Dextre (not visible) approaching the RRM activity board in March 2012. (Credit: NASA/CSA)
While riding on the end of Canadarm2, Dextre approaches the RRM module (on bottom platform, left side) to perform the Launch Lock Task. (Credit: NASA)