The U.S. Department of Defense is looking for ways to reuse space junk thousands of kilometers above Earth.
The Pentagon’s Defense Advanced Research Projects Agency (DARPA) has started a program called Phoenix, which seeks to recycle still-functioning pieces of defunct satellites and incorporate them into new space systems on the cheap.
The Phoenix program aims to use a robot mechanic-like vehicle to snag still-working antennas from the many retired and dead satellites in geosynchronous orbit — about 36,000 kilometers above Earth — and attach them to smaller “satlets,” or nanosatellites, launched from Earth.
“If this program is successful, space debris becomes space resource,” DARPA director Regina Dugan said in a statement.
Space debris — an accumulation of defunct satellites, spent rocket stages and other junk in orbit — has become a huge problem. There is so much junk circling the Earth that collisions among debris pieces could start to increase exponentially, leading to an ever-growing mound of rubble in orbit, a recent report from the U.S. National Research Council warned.
If it works, Phoenix could save the military a lot of money on launch costs, DARPA officials said. Antennas are big and bulky, requiring a lot of fuel to get off the ground, while lofting the antenna-less satlets would be much cheaper.
The Phoenix program envisions launching a so-called tender vehicle, a robotic satellite servicing station into geosynchronous orbit. The tender vehicle would be equipped with grasping mechanical arms and remote vision systems. The satlets would then be launched as extra payloads hitching rides into space on other satellites.
The tender vehicle would cruise over to a satlet, pluck it out of its housing and ferry it to the appropriate defunct satellite. The tender vehicle would then robotically attach the satlet to the comparatively massive antenna of a retired satellite creating a “new,” and relatively cheap, satellite using previously useless space junk.
Phoenix will require the development of new technologies, DARPA officials said, calling on the expertise of scientists and engineers in many fields.
“Satellites in GEO [geosynschronous Earth orbit] are not designed to be disassembled or repaired, so it’s not a matter of simply removing some nuts and bolts,” David Barnhart, DARPA’s Phoenix program manager, said. “This requires new remote imaging and robotics technology and special tools to grip, cut, and modify complex systems, since existing joints are usually molded or welded.”
The Phoenix program can look to some ground-based technology as a starting point, officials said. For example, it may incorporate elements of today’s telerobotics systems that allow doctors to perform surgery on patients thousands of kilometers away, as well as advanced remote imaging systems that enable oil drillers to view the ocean floor thousands of meters underwater.
But these capabilities would need to be re-engineered to operate in space, to meet the challenges imposed by the microgravity, high-vacuum and harsh-radiation environment of space.
The Phoenix program is also specifically looking for technologies to help develop a new class of satlets that can be launched more economically to geosynchronous orbit via existing ride-along services with commercial satellites, DARPA officials said. The agency plans to host two industry days in November for scientists and engineers interested in pitching ideas for the Phoenix program, they added.