Two NASA robotic arms Thursday played critical roles in the installation of what essentially is the last piece of the backbone of the International Space Station.
The space shuttle Discovery docked with the space station on Tuesday afternoon. The shuttle's seven-astronaut crew is delivering the S6 truss, which is the backbone piece, along with a nearly 5,000-pound, 230-foot set of solar arrays. The arrays are attached to the truss and may begin generating power for the space station as soon as Friday.
A robotic arm onboard the space shuttle, dubbed Canadarm, and a robotic arm onboard the space station, dubbed, in turn, Canadarm 2, were used Wednesday to unload the truss from the space shuttle's cargo bay, according to Mike Curie, a spokesman for NASA.
Thursday, astronauts Steve Swanson and Richard Arnold set out on a six-and-a-half-hour space walk to install the truss. Curie said that the robotic arm on the space station maneuvered the truss into place while the space walkers watched to make sure it was aligned exactly. Then the astronauts screwed in the bolts while Canadarm 2 held the truss in place. The power and data cables have been attached to the truss and are expected to be powered up later Thursday.
On Friday, the solar arrays are slated to be unfurled and set up. They are designed to gather energy through 32,800 solar cells and then transfer that power through the truss to the space station's batteries.
Curie said they simply couldn't do the work without the use of robotics.
"We rely heavily on the combination of robotics and astronauts to accomplish these tasks," said Curie in an interview with Computerworld. "Without Canadarm 2 and the original Canadarm on the shuttle, we wouldn't be able to move these heavy objects. We would never be able to complete the space shuttle without these robotics. They're essential to the construction of the International Space Station."
Last fall, NASA said that the future of space exploration will depend on humans and robots working hand-in-hand as manned and unmanned missions head back to the moon, to Mars and the farther expanses of space.
Carl Walz, director of advanced capabilities at NASA and a former astronaut, said, "We're just starting to scratch the surface of these concepts. It'll be absolutely critical. What we're trying to do is figure out how best to incorporate human exploration and robots. I think the nature of exploration will be different [because of robots]."
Another NASA robotic arm was installed on the space station last spring. Dextre -- a US$200 million, 12-foot-tall robot with a 30-foot wing span -- is designed to take on most of the maintenance jobs required outside of the space station, thus cutting back on the number of dangerous space walks the astronauts must make.
Curie said Dextre wasn't used to help unload or install the truss because it's designed for more detailed work, while Canadarm 2 is geared to take on more heavy-lifting. Dextre, Canadarm and Canadarm 2 were all built for NASA by the Canadian Space Agency, which is based in Saint-Hubert, Quebec.