Attacking hypersonic glide vehicle weapons can skim along the upper boundaries of the earth’s atmosphere, using trajectory and a speed of descent to destroy targets with unprecedented force.
Therefore, much discussion is underway regarding how best to defend against or stop these kinds of hypersonic missile attacks, in part because they occupy a specific area of the atmosphere which, at least at the moment, can be tough for sensors and missile defense interceptors to reach.
This dynamic, explained recently by Principal Pentagon Director for Hypersonics Michael White, means that hypersonic attacks moving through the highest areas of the earth’s atmosphere occupy what could be called an “in between space,” meaning they are too high for many ground-based radars and missile defense radars to reach… yet not high enough for space spaced missile defense interceptors to destroy.
“Our air defense systems and our missile defense systems are designed to operate on either side of that near-space operating zone,” White recently told reporters according to a Pentagon transcript..
Therefore, the Pentagon is moving quickly to close what could be a “gap” in defenses.
“Air defense systems work well up to 70,000 feet or so and are designed to have radars that look over—at the horizon to find low-altitude cruise missiles and be able to handle threats—aircraft and missile threats up to about 70,000 feet. Our ballistic missile systems are designed to look up for mid-course intercept, exoatmospheric intercept of ballistic missiles and all of our system elements are designed for that mission,” he explained.
Not only can hypersonic weapons fly at altitudes from 80,000 to 150,000 feet, thus higher than the 70,000 he mentioned, but White said these kinds of hypersonic attacks can travel at “sustained speeds,” making them difficult for some radar systems to track. While hypersonic weapons will undoubtedly travel fast, in many cases hitting a target in minutes, the longest window for a possible intercept would not be on its ascent or descent but rather during the bulk of its flight at these particular “near-space” altitudes.
“The challenge with hypersonic systems is that they fly in a region of the atmosphere, the hypersonic speed allows sustained flight in the upper regions of the atmosphere, so they fly at a range that some people call near-space, say between 80,000 and 150,000 feet. Without hypersonic speeds, you don’t have enough lift to fly at that altitude with the low densities. And so, hypersonic speed really enables sustained flight there,” White said.
So what is the solution to this kind of tactical predicament? Several things come to mind, perhaps the first of which might be an initial thought of “hypersonics vs. hypersonics.” Why not engineer defensive hypersonic systems able to travel through these otherwise difficult areas to reach? This kind of approach might benefit from advanced, high-speed sensing, AI-enabled algorithms facilitating detection in milliseconds to guide an interceptor moving at hypersonic speeds to collide with and destroy an attacking one. Perhaps satellite sensors can increasingly track hypersonic weapons and, ideally, function as some kind of cue or guidance “node” for interceptors.
Any kind of interceptor capable of destroying hypersonics would naturally need to move faster and perhaps be more agile than a space-traveling Ground Based Interceptor designed to take out intercontinental ballistic missiles (ICBMs). Targeting the main portion of a glide-vehicle’s flight through the air might offer the best opportunity for intercept, perhaps fostering a need for newer kinds of faster, near-space traveling interceptors.
Kris Osborn is the defense editor for the National Interest. Osborn previously served at the Pentagon as a Highly Qualified Expert with the Office of the Assistant Secretary of the Army—Acquisition, Logistics & Technology. Osborn has also worked as an anchor and on-air military specialist at national TV networks. He has appeared as a guest military expert on Fox News, MSNBC, The Military Channel, and The History Channel. He also has a Masters Degree in Comparative Literature from Columbia University.