Hypersonic Missile Defense May Depend on Low Earth Orbit Satellites

TR_123456 · Aug 9, 2021

An Antares rocket carrying a Cygnus resupply spacecraft is raised into a vertical position at NASA's Wallops Flight Facility in Virginia, February 5, 2020. Aubrey Gemignani / NASA via Getty Images

Sensors in relatively low orbits may be the best way to spot superfast missiles—but they can’t do the job alone.

WALLOPS ISLAND, Va.—The Antares rocket that’s launching Tuesday to replenish the International Space Station will be carrying a camera sensor with a unique missile-defense task: to begin gathering data that could help the U.S. more quickly detect and defend against hypersonic missiles.

The Prototype Infrared Payload, nicknamed “PIRPL,” was developed by Northrop Grumman and the Missile Defense Agency to see how low Earth orbit, or LEO, satellites might be used to help detect hypersonic missiles.

“So, tracking layers—looking at missile warning, missile tracking, those kinds of defense-related missions—those are usually done at higher orbits like geostationary orbit, with bigger sensors on longer-life satellites. Sometimes we call them national assets,” said a Space Development Agency official who briefed reporters on the condition they not be named.

But geostationary satellites operate at an altitude of 35,000 kilometers from the Earth’s surface, which makes it more difficult to rapidly discern the dim infrared signatures of hypersonic missiles against all the infrared noise, or clutter, generated by the Earth. A low Earth orbit satellite operates at about 1,000 kilometers, “which gives me a ton of better detection capability,” the official said.

“A maneuvering advanced hypersonic missile is not bright and that is why we need to innovate,” the official said.

When a target of interest is identified, the images collected have to be run through a decluttering process to refine out that dim signature.