The Defense Advanced Research Projects Agency (DARPA) has kicked off an initiative to harvest and re-use valuable components from dead satellites in geosynchronous orbit (GEO).
According to DARPA program manager David Barnhart, more than $300 billion worth of satellites are estimated to be in geosynchronous orbit 22,000 miles above the earth.
Although the retired satellites have gone offline for various reasons, many still have valuable components, such as antennas, that could last much longer than originally anticipated.
"When satellites in GEO 'retire,' they are put into a GEO disposal or 'graveyard' orbit," explained Barnhart.
"That graveyard potentially holds tens to more than a hundred retired satellites that have components that could be repurposed - with the willing knowledge and sanction of the satellite's owner."
As such, DARPA's Phoenix program seeks to develop technologies to cooperatively harvest and re-use valuable components from retired, nonworking satellites in GEO, while demonstrating the ability to create new space systems at greatly reduced cost.
If the program is successful, DARPA believes space debris - which often pose a threat to astronauts - may eventually become a valuable resource.
As expected, such a complex program would require diverse expertise from the international and nontraditional space communities. For example, ground-based robotics systems allow surgeons to perform telesurgery on a patient thousands of miles away, while advanced remote imaging systems used for offshore drilling view the ocean floor thousands of feet underwater.
These types of capabilities, if re-engineered for zero gravity, high-vacuum and harsh radiation, could be used in space to allow the repurposing of valuable antennas from retired GEO satellites.
"Satellites in GEO are not designed to be disassembled or repaired, so it's not a matter of simply removing some nuts and bolts. 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," said Barnhart.
"Another challenge is developing new remote operating procedures to hold two parts together so a third robotic 'hand' can join them with a third part, such as a fastener, all in zero gravity. For a person operating such robotics, the complexity is similar to trying to assemble via remote control multiple Legos at the same time while looking through a telescope."
To optimally deploy repurposed assets, the Phoenix program will develop low-cost, scalable electronics and structural modules capable of facilitating localized control and communication with each other and a master satellite (ala DARPA's System F6), that together harnesses the repurposed antennas.
Specifically, Phoenix seeks technologies for developing a new class of cheaper, small "satlets," or nanosatellites, which can be sent to GEO via existing ride-along services with commercial satellite launches and then robotically attached to the antenna of a nonfunctional cooperating satellite to essentially create a new space system.
A separate on-orbit "tender," or satellite servicing station would also be launched into GEO. Once the tender arrives on-orbit, the payload orbital delivery system (PODS) will be released from its ride-along host and linked with the tender to become part of the satellite servicing station's "tool belt." The tender would be equipped with grasping mechanical arms and remote vision systems to remove components and satlets from the PODS.