When Discovery's six astronauts take the final space shuttle ride to orbit in September, there'll be one more rider sitting in the back of the bus: Robonaut 2, the semi-humanoid robot created by NASA and GM.

The 300-pound (137-kilogram) robot, known as R2 for short, is being outfitted for its first tour of duty on the International Space Station - a tour that marks one small step toward a world where robots and humans work side by side in space.

Unfortunately, R2 can't take one small step right now: It's only a robo-head and torso, equipped with two arms complete with humanlike hands and five fingers. But that's enough to start seeing how humanoid androids perform in zero-gravity.

""This project exemplifies the promise that a future generation of robots can have both in space and on Earth, not as replacements for humans but as companions that can carry out key supporting roles," John Olson, director of NASA's Exploration Systems Integration Office, said in today's announcement about R2's itinerary. "The combined potential of humans and robots is a perfect example of the sum equaling more than the parts. It will allow us to go farther and achieve more than we can probably even imagine today."

The lessons learned on the final frontier could also be applied to factory floors on Earth - and that's why GM has been working so closely with NASA to get R2 ready for its tryout. Hand in robotic hand, so to speak.

Both NASA and GM have long track records in robotics. On the shuttle and the station, as well as in automotive factories, robotic arms are important tools of the trade. NASA even has a Canadian-built robot with a dextrous hand, known as Dextre, available for jobs on the space station's exterior. R2 could take that dexterity to a new level, in space as well in the factory.

"What we do is discuss potential missions and figure out which are the most synergistic with the GM factory needs," Alan Taub, the automaker's vice president for global research and development, told me. One of GM's key needs is to have a two-armed robot capable of handling flexible material that could too easily be ripped or ruined. Such a robot could be used, for example, to apply moisture-shielding material inside the doors of GM's cars, Taub said.

"It's a highly flexible material that needs careful positioning," he explained. "It's a very difficult task for humans today, one of the hardest jobs in the plant."

It turns out that's the type of job NASA astronauts could use some help with as well - for example, to place protective panels on the space station or future spacecraft. "By working on our problem, they discovered that they could in fact lift some of the flexible parts that they need to use if they're doing a space repair," Taub said.

R2 isn't yet ready for that kind of work. The prototype robot isn't hardy enough to stand up to the harsh environment of outer space. So, during the coming tour of duty, R2 will be kept inside the space station's Destiny laboratory, to see how it works in weightlessness and how it deals with radiation exposure.

The robot is currently undergoing vacuum and vibration testing on Earth. "It turns out that the processes for making it robust for one of our plants and making it robust for space are remarkably similar," Taub said. "GM brought some insights that NASA just jumped on. They're very different environments, but remarkably similar hardening technologies."

At first, R2 will have to be anchored in a test area on the space station, but eventually, R2 could conceivably roam around like R2D2 in "Star Wars."

"It's definitely not biped mobile, but you can put it on various types of chassis to make it mobile," Taub said. And someday, R2 might even get a chance to work on the station's exterior, alongside Dextre or human spacewalkers.

Right now, NASA and GM can't predict how far they'll be able to push Robonaut 2. A carbon copy of the robot is being kept down on Earth for further experimentation, and it's likely there'll be more advanced generations of humanoid androids in years to come. (For example, the Project M moonbot that some insiders have talked about.)

And GM isn't the only automaker taking advantage of space expertise: Ford and the United Space Alliance, the consortium that manages shuttle operations for NASA, are working together on virtual-reality simulation software that could be used to fine-tune the designs for spaceships or cars before they're actually built. Just this week, NASA and Chrysler announced an agreement for future technological collaboration.

Such partnerships aren't merely business deals. GM's Taub emphasized the inspirational side of working with NASA: If students see that working on industrial challenges can have cosmic applications, that could well increase their interest in science, technology, engineering and math - an academic sphere known collectively as STEM.

"Part of the message is to inspire more kids to go into the STEM curriculum," Taub said. "It's time to get kids excited about engineering and technology again."