Dextre robot lands a job

Dextre, the Canadian robot that lives outside the International Space Station, has its first major job: demonstrating how to refuel satellites.

NASA, which is backing the so-called Robotic Refueling Mission, hopes the trial run will lead to a new satellite servicing industry. Fuel, which is used to maneuver spacecraft in orbit, typically is the limiting factor in how long expensive communications and other satellites circling Earth can remain operational.

Equipment for the Robotic Refueling Mission is due to arrive at the space station next month aboard space shuttle Atlantis, NASA's final shuttle flight. The gear includes fittings and tools that Dextre can use on a sample collection of satellite fixtures that match what are on existing spacecraft, none of which were designed for servicing and refueling.

"We're trying to show that a robotic system can go to orbit and refuel a legacy satellite," said Benjamin Reed, the deputy project manager at NASA's Goddard Space Flight Center in Maryland.

The work builds on technologies developed by a Department of Defense research program called Orbital Express, which flew in 2007, as well as on NASA work to develop a potential robotic mission to service the Hubble Space Telescope.

Dextre will tackle the tasks over the next two years, paving the way for a follow-on mission to refuel a NOAA weather satellite. NASA plans to partner with a commercial company in hopes of spurring a new satellite servicing industry. The robot launched on that mission would be capable of refueling another nine satellites, Reed told Discovery News.

"That would provide each customer satellites with three years of life-extension fuel," he said.

There are currently about 360 operational commercial communications satellites and another 100 government-owned satellites orbiting Earth. "Every single one of them one day is going to run out of fuel and be thrown away. That's the way it's always been done. If a robot can go up and refuel it, you wouldn't have to throw it away," Reed said.

Because the satellites weren't designed with refueling in mind they have no navigational aids, no reflectors, nothing to help guide in an approaching spacecraft the technical hurdles are steep. The NASA team that developed tools and procedures for robotic servicing of Hubble has taken on that task.

In addition to refueling, Dextre will demonstrate limited repair capabilities. Since the same technology also could be used to disable satellites, Reed said NASA intends to be as open as possible about the technology and how it is to be used.

       Selman TENGÜZ

   Wednesday, May 18, 2011

       Talip BÖLÜKBAŞI

   Thursday, May 19, 2011