The Defense Advanced Research Projects Agency, the Pentagon's science wing, is developing a new type of satellite that can repair, refuel, and upgrade other satellites in high orbit.
The Robotic Servicing of Geosynchronous Satellites initiative could help extend the lives of expensive communications and surveillance spacecraft, thus reducing the need for replacement craft and also cutting down on the number of dead satellites cluttering up the space around Earth.
But there's a downside. "This technology, while immensely beneficial to satellite operators, could easily be used as a weapon system," Theresa Hitchens, a University of Maryland space expert, told me. The dual-use nature of the new servicing satellite, which DARPA expects to launch in 2019, could heighten tensions among spacefaring countries.
The servicing-satellite initiative began in 2016 but has gained momentum in recent months. In September, DARPA chose Palo Alto-based satellite-maker Space Systems Loral to partner with the agency on the new spacecraft.
Under the terms of the partnership, Space Systems Loral will design the basic vehicle. DARPA will build the payload, which will likely include high-precision robotic arms that can manipulate and modify other satellites, adding fuel or extra thrusters or repairing damaged or obsolete components.
The new servicing-satellite will work in geosynchronous orbits, or GEO, 22,000 miles above Earth's surface. "The US government operates far more satellites in GEO than any other nation," Dr. Gordon Roesler, the DARPA program manager, said in a 2016 interview in The Government Satellite Report, a trade publication.
"GEO satellites have experienced failures, malfunctions, schedule delays, coverage gaps, unforeseen maneuvers and other anomalous events," Roseler explained. "Because GEO satellites reside on or near a single orbital path, the RSGS servicer would travel among them with little propellant consumption, enabling it to perform many servicing missions before using up its own propellant."
But one country's orbital mechanic is another country's saboteur.
Read more: How to Prevent Space War
"The technology that lets you closely approach a satellite without that satellite’s cooperation can be used either to repair satellites that aren’t working or to interfere with them," Dr. Laura Grego, a space expert with the Massachusetts-based Union of Concerned Scientists, told me.
The United States, China, and Russia have all developed so-called "inspection satellites" that can maneuver close to other spacecraft in low orbits and examine them for malfunctions. NASA is also working on a low-orbit servicing satellite.
These low-orbit satellites are controversial. "You can probably equip them with lasers, maybe put some explosives on them," Anatoly Zak, an independent expert on the Russian space program, told me. "If [one] comes very close to some military satellite, it probably can do some harm."
The Trump administration is keenly aware of the potential for orbital sabotage. “Any harmful interference with or an attack upon critical components of our space architecture that directly affects this vital U.S. interest will be met with a deliberate response at a time, place, manner and domain of our choosing,” the administration warned in its new national security strategy.
Combine such a satellite’s inspection capability with the ability to physically manipulate another satellite and place this servicer in geosynchronous orbit where pricey spacecraft are neatly lined up, and you've got the makings of a powerful orbital weapon, one that could inspire a new arms race in space.
"If one of these service satellites gets close to a Chinese satellite without warning, or heaven forfend, accidentally runs into one during a time of high tensions, that would obviously not be a good thing," Hitchens warned. "The US, if it deploys service satellites, needs to be upfront about where they are and what they are doing."
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