As it plans LEO constellations, DoD must prepare to deal with congestion


“On National Security” appears in every issue of SpaceNews magazine. This column ran in the June 10, 2019 issue.

The buzzword in military space these days is “proliferated LEO,” which is Pentagon-speak for large numbers of small satellites in low Earth orbit.

LeoLabs of Menlo Park, California, uses this phased array radar near Fairbanks, Alaska, and another in Midland, Texas, to track spacecraft and debris. The mapping startup plans to build a third radar in New Zealand as part of its ongoing quest to become the Google Maps of low Earth orbit. Credit: Craig Heinselman

The first project of the newly created Space Development Agency will be to design a proliferated LEO architecture and figure out how it can support military activities in space such as missile detection, communications and global navigation. SDA Director Fred Kennedy believes that within a few years, DoD will be able to shift some capabilities from large spacecraft in higher orbits to small satellites closer to Earth.

Now we’re hearing that the National Reconnaissance Office is likewise ready to jump on the LEO bandwagon to take advantage of lower cost satellites and cheaper launch services. With a proliferated constellation of dozens of spacecraft, the government can take more risks, says Troy Meink, director of NRO’s geospatial intelligence directorate. “You can have a higher failure rate and be able to deal with that. Losing two out of 10 is not as bad as losing one of two.”

With the benefits of LEO come concerns, however. One is the growing congestion and danger of not knowing exactly what is up there.

“This is not just a DoD problem,” says LeoLabs founder and CEO Daniel Ceperley. “Very few people are used to the large constellations.”

LeoLabs operates a worldwide network of ground-based, phased-array radars that tracks objects in low orbits. Its primary customers are commercial satellite operators, regulatory and civilian space agencies, and insurance companies. LeoLabs does some work with DoD, but Ceperley expects the military will become a bigger customer as it moves to deploy more satellites in LEO.

Everyone is focused on building satellites, launching them and making sure they can downlink data, but much less thought is being given to the actual operation of a constellation in a congested environment, says Ceperley. “That’s where there’s a lot of challenge.”

All this is manageable, he says. There are roughly 1,000 active satellites in LEO today. If the huge broadband constellations that are now being developed come to fruition, the numbers could go up to 15,000. “I think they can all be safely put into LEO. It just requires much better active management,” Ceperley says.

Given the pace of commercial investment in space traffic management technologies, DoD should have access in the future to more sophisticated collision-prevention services that will alert operators about potential orbital crashes. Today, there’s no collision prevention information available outside of what U.S. Strategic Command sends directly to satellite operators, says Ceperley. “There’s a lot of talk about rules of the road and best practices for organizing constellations, but it’s not based on a lot of data.”

For DoD, one of the concerns is dealing with maneuvering satellites that may or may not have malicious intent but still pose hazards. A lot of satellites are using low impulse thrusters so operators can raise fleets of spacecraft slowly up to their operational altitude and bring them back down to burn up in the atmosphere. “There’s a lot more maneuvering going on,” Ceperley says. “Keeping track of those maneuvers and feeding those into collision prediction services has been a challenge in the past.” He says LeoLabs is developing new software systems and expanding its radar network precisely to fill the demand for more intelligence about what’s happening in space.

The U.S. Air Force is spending hundreds of millions of dollars on a Space Fence radar which is about to become operational and will help track much smaller objects than now possible. But that is not going to be enough to cope with the clutter and the proliferation of space junk, says Ceperley. DoD’s exquisite sensors are valuable for some activities but the military will need additional help keeping tabs on commercial activity and where the debris is going.

DoD today does not have enough sensors to adequately monitor the congestion in LEO, he says. If several dozen satellites are launched at one time, at least 10 or 20 will go untracked for weeks.

Those issues are going to become a bigger problem for the military and the intelligence community as LEO becomes more populated.

Sandra Erwin


Sandra Erwin covers military space for SpaceNews. She is a veteran national security journalist and former editor of National Defense magazine.