Geosynchronous Satellite Recycling Closer to Reality
They're vital to communications and many industries and also to the military. DARPA, not surprisingly, has a program to “harvest and reuse” components from retired, non-working satellites and create new ones.
DARPA posted a report about its Zero Robotics Autonomous Space Capture Challenge, in which high school teams developed algorithms to test the capture of tumbling objects in space by using mini-satellites aboard the International Space Station. This supports DARPA's Phoenix program, which has a goal of demonstrating technologies to "harvest and re-use valuable components from retired, nonworking communications satellites in geosynchronous orbit," which is 22,000 miles above the earth's surface.
This requires the ability to position a spacecraft and synchronize it with a tumbling object, then use tools to remove or attach necessary parts. Retired satellites tumble in their orbits at high speed.
While DARPA is working with teams of individuals around the world, it started with testing the algorithms to control a bowling ball-sized programmable SPHERES satellite on the space station. At lesat one of the finalist teams was able to approach the target and remain synchronized within the predefined capture region, according to its report.
The next step is to scale this work; DARPA explains that Phoenix "seeks to demonstrate around-the-clock, globally persistent communication capability for warfighters more economically, by robotically removing and re-using GEO-based space apertures and antennas from de-commissioned satellites in the graveyard or disposal orbit."
"The latest competition on the ISS helped identify key attributes in how to optimize fuel use and time to match an object's random tumble in space and be able to approach and dock with it safely," said Dave Barnhart, DARPA program manager. "The control procedures that were developed for the Zero Robotics Challenge will certainly benefit the Phoenix program, but they also potentially have much wider implications for space-based technologies. Our efforts can help to reduce the risks and costs of future complex satellite-to-satellite interactions in space to lower the barrier of entry for future space operations and missions."
The next Zero Robotics High School Tournament starts Sept. 8. For information, go to http://zerorobotics.mit.edu/.