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Canadarm2 Goes Operational

Canadarm2 was launched folded in half inside a metal pallet in the Shuttle’s payload bay to protect it from the forces of launch (and a possible emergency landing of the Shuttle.) This is why each of its two long booms must be unfolded and bolted together after it gets into space.

On their first spacewalk, Chris Hadfield and Scott Parazynski will remove eight large "superbolts" holding Canadarm2 inside the pallet, as well as eight thermal covers that protect the arm’s computers and cameras from the cold of space. Describing the covers as "billowy blankets", Hadfield said, "it will be like Christmas morning -- we’ll be unwrapping a huge present."

Next, the astronauts will unfold the booms manually and bolt the hinges in the middle. The procedure involves swinging the central "elbow" of the arm through 180 degrees to straighten the booms, a task Hadfield will perform while riding on the end of the Canadarm. "I’ll be holding the elbow in my hands as the Canadarm operator drives me around," he said. Once the booms are straightened, they won’t be folded up again; Canadarm2 is designed to be maintained and repaired in space and will never be returned to Earth.

When this task is completed, Hadfield and Parazynski will return to the Shuttle. The next day, Canadarm2 , still resting in its pallet, will be commanded from a computer inside the Station to reach out with one of its "hands" to grasp a power data grapple fixture on Destiny and "step out" of the pallet.

PDGFs are devices that provide electrical power and a video/data link between the Station and Canadarm2 . Eventually, many PDGFs will be placed around the Station’s external structure, which will allow the arm to literally walk hand-over-hand all over the Station.

On Day 6, Hadfield and Parazynski will go outside again to unplug the cables they attached to the pallet during the first EVA and to do some "rewiring" of these cables to power up the grapple fixture on Destiny to which Canadarm2 is attached. Canadarm2 will now receive power and computer commands through the Lab’s PDGF.

Its first real job will be to pick up the pallet and hand it back to the Canadarm, operated by Hadfield from inside the Shuttle. He will place the pallet in the payload bay for return to Earth. Canadarm2 will then be ready to assume its role in helping to build the Space Station.