As the U.S. Space Force grows from a command in the Air Force to the proposed sixth branch of the military, it will take on the space assets of the other branches, including DARPA's ghost robots in orbit, used to manipulate satellites in geosynchronous orbit.
The robotic arms of DARPA's Robotic Servicing of Geosynchronous Satellites program.
Yes, DARPA has robots in development that would orbit the earth, using their little robot arms and other tools to repair American and corporate satellites, but they would also be useful for taking out enemy satellites without triggering the dreaded "Kessler Effect," where damaging a single satellite dooms all satellites in orbit.
The robots are in development with the U.S. Naval Research Laboratory, selected by DARPA because it already has 15 years of experience in space robotics. The basic idea is to develop robots that can maintain satellites in orbit.
Right now, once a satellite goes into orbit, that's basically it. It can do its job, but there's little chance to repair it or its payload. If its payload becomes outdated or if it's hit by space debris, the damage is permanent. Something as small as bits of dust or flakes of paint can sideline a multi-million dollar asset.
Astronauts repair the Hubble Telescope in the space shuttle bay of Endeavour.
One of the few exceptions to this rule, the Hubble Space Telescope, has been repaired five times, but this required five different trips by the Space Shuttle to the Hubble.
What DARPA wants is a group of satellites equipped with repair tools, including robot arms, that could fix their brethren while still in orbit. While the bulk of satellites are in low-earth orbit, the Robotic Servicing of Geosynchronous Satellites program sets its sites higher, at geosynchronous orbit.
Geosynchronous orbits typically include weather, surveillance, and communications satellites, all assets that the military needs to keep in working order.
But the U.S., China, and Russia are also in an arms race to figure out how to destroy each other's satellites without risking their own.
The greatest challenge comes at low-earth orbit where there are a lot more satellites in a lot less space. Satellites in LEO can be destroyed with anti-ballistic missile weapons, but doing so could create a chain reaction where the fast-moving debris from the killed satellites starts taking out other satellites.
This chain reaction is known as the "Kessler Effect," and it works similar to a nuclear reaction, but with satellites in orbit instead of nuclei in dense metal. Once it gets started, it's self-sustaining and all-destructive.
The Space Shuttle Atlantis takes off in 2010. After a catastrophe triggers the Kessler Effect, it could make exiting Earth's atmosphere impossible for nearly a generation.
(Nasa Tony Gray and Tom Farrar)
A space attack or accident that triggers the Kessler Effect could make exiting Earth's atmosphere too dangerous for generations, and it's guaranteed to destroy friendly and enemy satellites alike.
So, if the Space Force ever does have to fight America's wars in orbit, they need tools that can disable enemy satellites without putting out a lot of debris. These satellite repair bots could dock with adversary assets and disassemble or otherwise disable them.
No fast-moving debris, no catastrophic chain reaction, no muss, no fuss.
Artist's concept of the robotic servicing vehicle for repairing satellites.
For now, though, there are no stated plans to use the satellites for anything but repairs and upgrades. In fact, the bots aren't even expected to take flight on military rockets when they first launch in 2021. Instead, they will reach orbit on commercial launches of private spacecraft.
And their repairs won't be limited to military customers, either. Private companies can join a "cooperative servicing" agreement to obtain the services of one of the robots. Each robot is expected repair up to 20 space assets while in space, so a single repair launch can revitalize or repair 20 existing satellites.
Or, in times of war, conduct a controlled disabling of 20 satellites — depending on how it's deployed.