By
The Associated Press
CAPE CANAVERAL, Fla. - A robotic inchworm - all 693 inches of it - is about to climb all the way to the international space station.
It is the most visibly high-tech, sci-fi piece of the space station jigsaw puzzle to date: a billion-dollar construction crane that has a hand on each end and is capable of walking across the orbiting complex, end over end, in inchwormlike fashion.
It can touch, via force-sensing mechanisms, and see, via cameras and computers. It also has a self-protective mechanism to prevent it from banging into itself.
Even normally stoic NASA engineers are wowed as Thursday's launch approaches.
"We get a little bit jaded," says the lead flight director, Phil Engelauf. But the robotic arm "really does capture people's imagination."
"This is not a bunch of cans that just sit there hooked up to the station. This thing moves. It crawls around," Engelauf says. "This is space stuff."
The 57-foot, 9-inch, jointed crane is called the Big Arm, to distinguish it from the Little Arm that stretches 50 feet, 3 inches and flies on NASA's space shuttles. It has 14-inch biceps and seven joints: three at the shoulder, three at the wrist and one at the elbow. The joints can rotate plus or minus 270 degrees, providing more range of motion than a human arm.
One of the two hands must be plugged into one of the sockets on the space station at all times for the arm to come alive with power and computer data. Fingers will be added on a later mission.
The arm, made of high-strength aluminum, stainless steel and graphite epoxy, is so heavy - 3,618 pounds - that it cannot support its own weight on Earth. For testing, it had to be disconnected at the elbow and supported with a massive rig. It is Canada's major contribution to space station Alpha.
"It's cutting edge," though the conceptual design goes back to President Reagan's proposed Freedom space station in 1984, says Savi Sachdev, acting director general of space systems for the Canadian Space Agency.
The robotic arm was originally meant to pull in an approaching space shuttle and dock it if the shuttle could not fly in on its own - a task the arm could perform, Sachdev says.
The most internationally diverse shuttle crew ever - four U.S. astronauts, one Italian, one Russian and one Canadian - will deliver the robotic arm aboard Endeavour and install it in what is probably NASA's most complicated robotics mission to date.
The shuttle's Little Arm will hook the Big Arm to the space station. Once the Big Arm is unfolded by spacewalking astronauts and grabs onto its proper space station berth, it will hand its 3,000-pound packing crate to the Little Arm. The Little Arm will put the crate back in the shuttle for return to Earth.
That handshake is sure to be the highlight of the 11-day shuttle mission. Canadian astronaut Chris Hadfield sees it as a symbolic "baton pass" between the two arms.
The Big Arm is needed to attach a pressure chamber for spacewalking astronauts to the station in June and to attach solar wings in 2002 and 2003, since the shuttle arm does not have the reach for those jobs.
The arm eventually will have a rail car to move over greater distances and, hopefully, will relieve astronauts of potentially risky spacewalking chores outside the space station.
"It's going to be real exciting to see it up there and all put together and operating after a large number of years having worked on it," Sachdev says. "It's so visible, it's so high-tech that it's definitely a source of pride."
