DARPA video outlines progress of Phoenix satellite re-purposing project
By David Szondy
January 25, 2013
The Defense Advanced Research Projects Agency (DARPA) has released a new video showing the progress of its Phoenix project, which aims at salvaging parts from defunct communications satellites to build new ones. Based on a new class of nanosatellites and a robotic “tender,” its purpose is to use repurposed satellites to construct a new communications net for the military at low cost.
One reason why operating communications satellites is so expensive is because it’s so wasteful. Currently, when a geosynchronous satellite reaches the end of its useful life, or just runs out of fuel to keep it from drifting, it’s dispatched to a “graveyard” region of space to prevent it from becoming a navigational hazard. This is unfortunate because many satellite components are still perfectly good, and it would be much cheaper to salvage antennas, solar panels and other bits from satellites already in orbit than sending new ones up from Earth.
The Phoenix project is intended to develop technologies to reuse components – specifically antennas – to provide American and allied soldiers with persistent communications via a fleet of repurposed antennas turned into new communications satellites.
The basis of this initiative are nanosatellites known as satlets, that are carried in what’s called a Payload Orbital Delivery System (PODS). These PODS would be sent into orbit as a piggyback payload with other larger satellites. Once in space, they would rendezvous with a “tender” spacecraft, which is a sort of robotic salvor craft. The PODS would be taken onboard the tender and the latter would intercept a dead satellite in graveyard orbit. Once on station, the remotely-operated tender would sever an antenna from the satellite using its robotic arms and then install the satlets in the antenna, turning it into a new communications relay.
This seems like a relatively straightforward exercise in telepresence and robotics not unlike remote surgery, but bear in mind that this surgery is being carried out in hard vacuum at a distance of 22,000 miles (36,000 km) involving a dead satellite and several autonomous electronics packages. That means that there’s a lot of new technology to be developed before the first salvage mission launches.
DARPA is working on developing radiation-tolerant microelectronics; wireless mobile platforms; micro-miniature guidance and control measurement units; robotic manipulators and tool changeout mechanisms; telepresence technologies; thermal management for electronics; and new materials.
The video (at the bottom of the page) demonstrates the progress the project has made since technical work began in July of last year. It shows an animated salvage operation while inserts show work being done on Earth to make this a reality. This work includes such milestones as development of a robotic arm with gripping and adhesion capabilities for satellite work; micro-camera prototypes; hyper-dexterous robot modules; a robotic gripper prototype; 10,000-eV differential discharge vacuum testing to protect electronics from static discharges; teleoperations software testing in simulations; testing of boom severing and debris generation; and satlet attitude control testing.
“Today, satellites are not built to be modified or repaired in space,” said Dave Barnhart, DARPA program manager. “Therefore, to enable an architecture that can reuse or repurpose on-orbit components requires us to create new technologies and new capabilities. This progress report gives the community a better sense of how we are doing on the challenges we may face and the technologies needed to help us meet our goals.”
For the next phase of development, DARPA intends to make a Broad Agency Announcement (BAA) to solicit new technologies for the project, such as low-cost software and hardware for rendezvous and proximity operations, test facilities for robotic systems with complex, interconnected movements, and virtual ground station operations. A Proposers’ Day will be held on February 8th. DARPA plans an orbital test of the system in 2015.