Astronauts are getting a helping hand in servicing the International Space Station (ISS): a 12-by-8-foot two-armed robot that can perform tasks like replacing batteries or damaged parts on the station's exterior. Such risky tasks are currently performed by the astronauts, who are tethered to a robotic arm.

The new robot, named Dextre, was built by the Canadian Space Agency, and is the third and final piece of its Mobile Servicing System for the ISS. According to Pierre Jean, the acting program manager for the Canadian Space Station Program, Dextre is the most sophisticated robot ever to fly in space.

Each of Dextre's two arms extends almost 11 feet and has seven joints so that it can twist and bend more than a human arm. The robot's "hands" are equipped with grippers to grab objects and built-in socket wrenches for bolting down parts. A rack attached to its waist will carry additional robotic tools. Dextre can replace everything from failed devices as small as a phone book to objects weighing as much as 1,000 pounds, in part because it has a sense of touch--it can "feel" the amount of force necessary.

Dextre will connect to either the Canadarm2, a 60-foot robotic arm with seven motorized joints, or a mobile base that runs along rails connected to the station. The Canadarm2 and the mobile base are the two other parts of the Canadian system delivered to the station in 2001 and 2002. Dextre will be operated by the astronauts on the ISS or the mission control center in Houston.

Dextre flew to space onboard the Space Shuttle Endeavour this morning from Kennedy Space Center in Florida. In the course of the 16-day shuttle mission--the longest flight ever to the station--the astronauts will conduct five space walks, which will include the assembly of the $210 million robot. Dextre will start work on the station in 2009 and have a 15-year working life.

The robot will serve as an important element in continuing to build and maintain the space station, and it can alleviate the risks associated with astronauts going into space to do mundane tasks, but it will not serve as their replacement. Astronauts' expertise and dexterity is still required for complicated tasks during space missions, including the assembly of the Japanese scientific laboratory, Kibo. (Endeavour is also carrying the first part of the lab to the ISS.) Dextre is, however, a significant step in the future of robotics in space.