When the multi-million-dollar satellites running our communications, GPS, radio and television services malfunction or run out of fuel, they are decommissioned. Depending on their proximity to Earth, they are either flown towards the atmosphere to burn up, or propelled to a region more than 23,600 miles (38,000 kilometers) away, known as the graveyard orbit, where the satellite’s remains won’t pose a threat to other spacecraft.
The problem with this system is that the technology onboard the satellite may be working, but it all gets tossed away with the spacecraft simply because repairs or refueling are not possible.
“There is no other area of human activity where we build something that’s worth a half-billion dollars or a billion dollars, and never look at it again, never fix it, and never upgrade it,” says
Gordon Roesler, program manager at the U.S. Defense Advanced Research Projects Agency (DARPA). “This is about changing that.”
Making repairs in space
Fortunately, the advanced robotics onboard new satellite servicing projects are intended to reduce the number of satellites facing this type of untimely retirement. Servicing spacecraft can repair, reposition, and refuel satellites using robotic arms, and will eventually be able to assemble satellites entirely in space.
Satellite servicing could eliminate the need for governments and companies to invest millions — and sometimes billions — into designing, building, and launching a replacement satellite every time repairs or fuel are needed. Servicing would also serve a national security role, as many government satellites relay critical information that shouldn’t be disrupted. The technology even has the potential to help humans reach Mars.
The United States government is working with Space Systems Loral (SSL), a commercial satellite manufacturer based in Palo Alto, California, to develop technology for two distinct satellite servicing projects.
First, DARPA is working with SSL on the Robotic Servicing of Geosynchronous Satellites (RSGS) program, for which Roesler is the program manager. DARPA and SSL seek to develop and demonstrate technologies that will enable cooperative inspection and servicing of satellites in geosynchronous orbit (GEO) — a high-altitude orbit about 22,300 miles (36,000 km) above Earth where many government and commercial communications satellites operate. This joint effort is expected to radically lower the risk and cost of operating in GEO.
SSL is also working on NASA’s Restore-L Mission, which will demonstrate servicing technology for spacecraft in low-Earth orbit between 99 and 1,200 miles (160 and 1,900 km). This is where the International Space Station (ISS), the Hubble Space Telescope, and many Earth-observation and research satellites are located.