June 21, 2012
Credit: Credit: NASA
HOUSTON — NASA and Canadian Space Agency (CSA) ground control teams combined efforts June 19-20 to begin the second phase of a robotic refueling demonstration outside the International Space Station, a pioneering effort to establish engineering strategies for extending the operating lives of aging satellites.
The three-day second phase of the two-year, $22.6 million Robotic Refueling Mission (RRM) employes the 58-ft.-long Canadarm2; Canada’s Special Purpose Dextrous Manipulator (Dextre), a two-armed, 11.5-ft.-long robotic handyman; and the Goddard Space Flight Center’s satellite simulator, an engineering demonstrator delivered and installed on the station’s long solar power truss by the crew of NASA’s final shuttle mission, STS-135, in July 2011.
The washing machine-sized demonstrator serves as a 3-D task board and tool storage device. The development effort features refueling techniques for satellites not initially designed to be refueled in orbit.
Working without the station’s six-member crew, ground control teams at St. Hubert, Quebec, and NASA’s Mission Control in Houston placed Dextre in the grasp of the larger robot arm for the first of three overnight sessions.
During the first session, Dextre pulled a multifunction tool from the Goddard demonstrator to remove and store a two-way T-valve. In similar fashion, Dextre will wield adapter tools to remove a gas cap from the demonstrator and simulate the penetration of the fuel tank seal installed prior to most satellite launches.
The first phase of the RRM demo was successfully carried out in March, with Canadarm2 and Dextre again responding to joint NASA and CSA commands for the checkout and activation of the Goddard demonstrators’s safety cap removal, wire cutter and multifunction tools. The three-day exercise simulated the release of launch locks on tool adapters and the severing of lock wires of the type used to close out fuel and coolant valve fittings on many satellites.
The final phase of the refueling mission demonstration is currently scheduled for later this year. Ground controllers will use the Canadarm2 and Dextre to demonstrate the manipulation of the thermal blankets that jacket satellites, electrical cap extraction and actual refueling. The satellite simulator is equipped with a nozzle tool, a half-gallon of ethanol fuel and a test fuel reservoir for the transfer task that will mark the third phase of the engineering test.