Sunday, March 16, 2008
Spacewalkers attached Canadian robot's mechanical arms
Two spacewalking astronauts attached 11-foot arms to the international space station's huge new robot on Sunday, preparing the giant machine for its handyman job on the orbital outpost.
The Canadian-built robot, named Dextre, will stand 12 feet and have a mass of 3,400 pounds when it's fully assembled. It is designed to assist spacewalking astronauts and possibly someday take over some of the tougher chores, like lugging around big replacement parts.
The already challenging outing turned grueling as Linnehan and fellow spacewalker Michael Foreman struggled to release one of the robot's arms from the transport bed where it had been latched down for launch.
Two of the bolts wouldn't budge, even when the astronauts banged on them and yanked as hard as they could. They had to use a pry bar to get it out.
The other arm came out much more smoothly and quickly, paving the way for Linnehan to pull up Dextre's body 60 degrees, like Frankenstein rising from his bed. That was the ideal position for plugging in Dextre's gangly arms to its shoulders.
Two US astronauts, working outside the International Space Station early Sunday, attached mechanical arms to a Canadian-made robot, enabling it to take over human tasks and reducing the need for future risky spacewalks.
Mission Specialists Richard Linnehan and Mike Foreman finished their task at about 3:00 am (0700 GMT), stowing away instruments and making their way into the station's airlock.
But their job got slightly complicated early in the seven-hour spacewalk when they encountered trouble unscrewing a couple of fasteners and removing one of the robot Dextre's arms from its storage container.
The problem was eventually resolved with the help of a simple crowbar. But as a result, "the spacewalkers fell about 45 minutes behind their timeline," said a spokesman for the National Aeronautics and Space Administration (NASA).
Linnehan and Foreman, who arrived last week aboard shuttle Endeavour, recouped most of the lost time, performing their task using socket wrenches and drills to bolt the Dextre robot's two 11-foot (3.3 meter) arms.
Mission Specialist Robert Behnken coordinated the spacewalk activities from inside the orbital complex while Endeavour pilot Gregory Johnson and space station engineer Garrett Reisman operate Canadarm2.
The hitch notwithstanding, astronaut Steve Robinson, monitoring the events from Mission Control in Houston, Texas, offered all involved hearty congratulations.
Pierre Jean, a program director from the Canadian Space Agency, echoed the view saying the crew did "a fantastic job."
The robot, which was re-powered immediately after the walk, will be able to handle maintenance tasks that have been performed by spacewalkers, allowing astronauts to focus on research inside the orbiting outpost.
"Dextre looks quite a bit different today," observed NASA flight director Dana Weigel. "It's almost fully assembled: It has two hands, two arms and the main body is pivoted up."
Astronauts installed Europe's first space laboratory in a shuttle Atlantis mission last month and Endeavour's crew added the first of three parts of Japan's Kibo research facility this week.
Dextre, sent up on Endeavour which is docked with the space station, is the third and final component of the Canadarm Remote Manipulator System, the robotic arm that is Canada's vital contribution to the station.
The 200-million-dollar robot encountered a technical glitch before its assembly, but the problem was resolved in time for Saturday's spacewalk.
The 1.56-tonne robot will conduct operations such as replacing small components on the station's exterior -- tasks which until now required a human touch.
Its presence will boost crew safety by reducing the number of hours that astronauts will have to be outside the station on spacewalks, and thus allowing them to focus on other tasks such as conducting scientific experiments in micro-gravity, according to the Canadian Space Agency.
Dextre's two hands are each about the size of a small microwave oven. They are equipped with built-in socket wrenches, retractable claws used to grip objects, and remote-control high-resolution cameras.
The robot's human-like upper torso swivels at the waist, and its arms were designed with seven joints to provide it with maximum versatility. Umbilical connectors provide power and data connectivity.
With Dextre delivered to ISS in nine separate pieces, the astronauts will use three of the Endeavour mission's five spacewalks to get it up and running.
Linnehan and fellow astronaut Garrett Reisman conducted the Endeavour mission's first spacewalk Friday to lay the groundwork for the robot's complicated assembly.
Dextre's assembly will be complete with a third spacewalk set to start Monday.
NASA plans to finish building the International Space Station by 2010, at which time it will retire its three-shuttle fleet.