WASHINGTON — As the Pentagon continues to recover the remnants of the Chinese spy balloon shot down Feb. 4 off the coast of South Carolina, the Biden administration is forming an interagency group to investigate these aerial surveillance objects and study options for their detection and analysis.

One of those options would be to “tune” the U.S. military’s space surveillance sensors to help detect high-altitude aerial surveillance platforms in the upper layer of the atmosphere, John Plumb, assistant secretary of defense for space policy, said Feb. 14.

Speaking at a Mitchell Institute for Aerospace Studies event, Plumb said his office has participated in multi-agency discussions on the implications of China deploying spy balloons over U.S. airspace. “Obviously the U.S. government’s been focused on this issue for a couple of weeks now, including myself,” he said.

The balloon incident led the North American Aerospace Defense Command (NORAD) to alter the detection parameters of its radar tracking sensors inside U.S. and Canadian airspace so this past weekend it was able to identify small objects that traditionally it would not track.

White House National Security Council spokesman John Kirby said “slow-moving, high-altitude objects, even as large as the Chinese spy balloon, which was the size of three school buses, are difficult to track by radar.” Speaking with reporters Feb. 13, Kirby said NORAD is adjusting its radar tracking methods.

Plumb explained there is “sensor overlap” in the military’s network of conventional radars, phased-array radars and telescopes that are used for air defense, missile defense and space domain awareness.

The systems that provide space domain awareness “can also be tuned, of course, to look at the stratosphere,” he said. 

The military’s collection of sensors is called the Space Surveillance Network, with systems dispersed across multiple sites worldwide. NORAD first deployed these sensors during the Cold War as an early warning system to detect ballistic missiles.

“How to tune those, or understand how to use the information coming back from them to get better awareness of that domain, is definitely part of the solution” to the detection of high-altitude balloons, Plumb added.

When sensors are multi-use, he said, the challenge is “figuring out the right balance of resources” across different parts of the sensor network. “That is really an important piece going forward.”

Mitchell Institute chair Kevin Chilton, a retired U.S. Air Force general, noted that until the recent discovery of the Chinese balloon, that section of the higher atmosphere was not getting much attention. “There wasn’t a lot going on there. So maybe our focus was a little lower in the atmosphere, and now we have to pay attention,” Chilton told Plumb.

Plumb pointed out that U.S. military radars are trained for cruise missile threats, and the balloon problem is not just a Department of Defense issue.

“The FAA [Federal Aviation Administration] is supposed to regulate our airspace and the airspace keeps going up past commercial jets,” Plumb added. “And so I think this kind of growing awareness of this problem is going to be part of this conversation.”

Layers of the atmosphere. Credit: NASA

Sandra Erwin writes about military space programs, policy, technology and the industry that supports this sector. She has covered the military, the Pentagon, Congress and the defense industry for nearly two decades as editor of NDIA’s National Defense...