Robotic-Servicing Testbed Is Being Upgraded

By Frank Morring, Jr.
Source: Aviation Week & Space Technology

“As we started trying to maximize the use of the payload, we decided it was better to use what we call a multifunction tool that can use multiple adaptors,” McGuire told the second annual ISS research and development conference here. “So the multifunction tool can pick up each of these adaptors, similar to if you were using a socket wrench in your garage, and you wanted to change out the sockets.”

The RRM flew to space on the final space shuttle mission in July 2011, and since then has carried out a variety of tasks in the experiment's first phase. Among the tasks completed were using the robot to: cut wire, manipulate the thermal blankets that typically cover the hardware servicing-spacecraft must handle, remove a variety of the caps that are found on operational satellites and transfer the simulated storable propellant through a typical fill-and-drain valve.

Controllers from NASA and the CSA, working from consoles at Mission Control Center-Houston, tele-operated Dextre and the RRM toolkit during experiment sessions. The tests went extremely well, says McGuire, with none of the redundant systems on the testbed put to use because of a problem with a primary. Each tool was equipped with a pair of close-up engineering cameras focused on the work area, which proved valuable in preventing jams from misalignment.

Ultimately, the Satellite Services Capabilities Office at Goddard plans to use the station to test a variety of robotic technologies that will be needed for deep-space human exploration, including on-orbit assembly of Earth-departure stages and habitats for long-duration missions. The next step, RRM Phase II, will add one “task board” to the testbed at an empty slot, and replace another board with a new one carrying different hardware for tasks.

A new tool dubbed Vipir, for visual inspection poseable invertebrate robot tool, will be included in the Phase II manifest to demonstrate semi-autonomous internal inspections of orbiting spacecraft. Vipir will maneuver a camera into the simulated spacecraft structure, where it will encounter “decision boxes” and try to find a way through them without getting stuck, according to McGuire.

Also on the Phase II agenda will be reassembly of cryogenic valves disconnected during Phase I. “We're going to take the next step in complexity, and show how we can now start putting back some of these components that we took apart,” McGuire says. “Now that you have an open fitting sitting there, how do you attach to that fitting?”

Other new tasks will include electrical work with the robot manipulating connectors while a solar-powered LED light shows engineers on the ground when connections have been made, and a plugging experiment with an open aluminum tube that will be checked with pressurized nitrogen and a gauge.

“It's one thing to install a vent plug,” McGuire says. “It's another thing to convince people that we are sealing the tube. . . . The ISS continues to be an invaluable testbed for this type of work.”

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