International Space Station Update: Robotic Refueling Experiments Look Good

Dextre robotic controls (on right) work on the RRM module.

Dextre is a robotic Instrument that works on the outside of the International Space Station. Built by the Canadian Space Agency, Dextre includes manipulator hands and tools that astronauts use to grasp satellites and experiments, move them around, and operate exterior controls. The RRM (Robotic Refueling Mission) is NASA's program to practice combining human and robotic skills to refuel and repair satellites in space.

The RRM module assists the NASA engineers in designing procedure steps and astronaut skills to perform tasks that would normally be done by an astronaut in a spacesuit making a dangerous EVA (spacewalk). The success of these experiments will help ISS astronauts and ground mission controllers to service space vehicles while in orbit of Earth.

The refueling aspect of the mission is very intriguing. NASA is making plans to save launch weight and launch costs by preparing "fuel depots" in orbit. When a space craft reaches orbit, the Refueling robots can then fuel up the space craft''s engines prior to launching outward to other planets or destinations. Refueling would also extend the life of satellites whose station-keeping thrusters have run out of propellant. Extending the serviceable life of satellites will save millions of dollars.

For long-duration flights, it would be possible to send fuel to distant locations and then fuel up a spacecraft for a return home. This new capability opens up new possibilities for exploring the solar system.

During March 7-9, astronauts on the ISS and NASA mission controllers were able to successfully pass many of the tests that will be needed to master before working on real satellites. One test included working Dextre's precision cutting tools to slip under two small wires, and cut them with only a few millimeters of room to spare. This type of precision will be absolutely necessary in making future repairs to spacecraft, such as servicing Hubble.

By Mark Daymont
Space Center Educator