Satellites don't last forever. They're expensive to launch, technically challenging to maintain and like all machines, they eventually putter out. But the Defense Advanced Research Projects Agency (DARPA) has an ambitious plan to service -- and even recycle -- satellites using robotics.
Today, when a satellite fails, it is a total loss. The satellite either burns up in Earth's atmosphere or lifelessly orbits the planet until a replacement is launched. DARPA's Phoenix program is a plan to change that cycle by sending robots to scavenge parts from dead satellites and attach them to miniature "satlets" to reuse.
The main item of interest for DARPA researchers is how to reuse the antennae of functionless satellites. While most satellites are uniquely designed to serve their particular function, certain pieces of the spacecraft could be recycled - including the antennae and solar arrays.
In a press conference Tuesday, DARPA project manager for Phoenix David Barnhart pointed out that most of the objects floating around Earth are debris, discarded space parts and dead satellites. Out of 1,300 "space objects," only 500 are functioning satellites. If Phoenix could revive just a small part of that junk, it could prove to be a cost-effective way of maintaining America's space fleet.
DARPA's Phoenix website describes how a satellite salvage operation might work:
The Phoenix program envisions developing a new class of very small 'satlets,' similar to nano satellites, which could be sent to the GEO region more economically as a "ride along" on a commercial satellite launch, and then attached to the antenna of a non-functional cooperating satellite robotically, essentially creating a new space system. A payload orbital delivery system, or PODS, will also be designed to safely house the satlets for transport aboard a commercial satellite launch. A separate on-orbit 'tender,' or satellite servicing satellite is also expected to be built and launched into GEO. Once the tender arrives on orbit, the PODS would then be released from its ride-along host and link up with the tender to become part of the satellite servicing station's 'tool belt.' The tender plans to be equipped with grasping mechanical arms for removing the satlets and components from the PODS using unique space tools to be developed in the program.
The defense agency plans to start the first Phoenix mission in 2015. DARPA is targeting 140 dead satellites and hopes to be able to recover their antennae. If the program is a success, it could theoretically point the way towards a self-sustaining future where satellites could be modified and repaired in orbit, drastically reducing the cost of maintaining the U.S. satellite fleet.