Canadian Space Agency

It's a bummer running out of gas, especially when the nearest station is 22,000 miles away.

But a project to set up a gas station on the International Space Station made a big leap forward this week with the successful refueling of a mock satellite by a robot.

Dextre, a twin-armed robot from Canada, topped off the fuel tank in the mockup, showing how satellites' life can be extended, according to the Canadian Space Agency (CSA).

Operating on the Robotic Refueling Mission (RRM) module, Dextre removed safety caps and cut through retaining wires before transferring liquid ethanol to the mockup, which is about the size of a washing machine.

The CSA-NASA achievement is the first of its kind, and may help reduce the growing pile of dead satellites and space junk orbiting overhead.

"The ability to refuel satellites in space could one day save satellite operators from the significant costs of building and launching new replacement satellites," the CSA said in a release.

"With over 1,100 active satellites currently operating in the near-Earth environment (many of them worth hundreds of millions of dollars), and an additional 2,500 inactive satellites still orbiting around our planet, the savings could be substantial."

Speaking of space junk, DARPA meanwhile has released a new video describing a rather different approach to the problem.

The agency's Phoenix Program, which began last July, proposes building small robots that would cannibalize dead satellites for their valuable parts.

The orbital recycling would involve "satlets" that would piggyback on commercial satellite launches. Other tender satellites would help by deploying grasping mechanical arms.

The animation below makes it all look very smooth and elegant, and there's been some progress in developing the necessary tools. The Swiss Space Center has a similar janitor satellite concept, but it's more focused on cleaning up and would send junk toward Earth to burn up on reentry.

We'll look forward to the first test of the DARPA idea, slated for 2015.