Missile defense has been a priority in the United States for decades, in no small part because the threat posed by long-range, nuclear-tipped ballistic missiles remains as one of the few direct threats to the American mainland that could arise with little to no warning. In today’s world, it would be all but impossible to sneak up to American shores with a sizable military contingent. Still, for the most part, the only thing stopping a nation from flinging nukes at the U.S. from across the sea is the assurance America will retaliate in kind.

Now, with hypersonic missile platforms nearing service in both Chinese and Russian militaries and both nations fielding new nuclear intercontinental ballistic missiles designed specifically to circumvent America’s layered approach to missile defense, Uncle Sam is on the hunt for new ways to counter the threats posed by advanced missile platforms. Some believe it’s been found in a rather science fiction-sounding endeavor: deploying directed-energy weapons to engage and destroy missiles.

Particle beam weapons work, to a certain extent, like lasers and are often referred to as “heat rays.” However, unlike lasers, particle beams work by accelerating particles (usually neutrons) without an electric charge to near-light speed velocities. When that beam of accelerated particles hits an intended target, the neutrons fired knock protons out of the nucleus of particles they encounter, creating heat.

That means particle beams don’t just interact with the surface of a target the way lasers do, but instead, they can penetrate the surface and affect a missile’s internal systems as well. While reflective surfaces can be used as an occasional means to redirect lasers, particles beams have no such issue, penetrating directly though the mirrored surface and wreaking havoc on the intended target.

Deploying such a weapon in space would be no small task. In order to function, a neutral particle beam weapon would require far more than an extremely capable targeting system (to hit missiles traveling at thousands of miles per hour). It would also need a particle accelerator, a power supply capable of sustaining such a weapon, a means of power storage (batteries), and an extremely hardened communications system.

“It’s a very short timeline, first to even know where it (the missile) is coming from,” an unnamed official told Defense One about the project. “It’s less than a couple minutes before it leaves the atmosphere. So you have to have a weapon that’s on station, that’s not going to be taken out by air batteries and so we have been looking at directed-energy applications for that. But you have to scale up power to that megawatt class. You’ve got to reduce the weight. You’ve got to have a power source. It’s a challenge, technically.”

Despite these hurdles, the Pentagon seems confident it can have a weapon of this sort in orbit as soon as 2023.

“We’ve come a long way in terms of the technology we use today to where a full, all-up system wouldn’t be the size of three of these conference rooms, right? We now believe we can get it down to a package that we can put on as part of a payload to be placed on orbit,” the official said.

“Power generation, beam formation, the accelerometer that’s required to get there and what it takes to neutralize that beam, that capability has been matured and there are technologies that we can use today to miniaturize.”

It’s important to note that having one of these systems in orbit in the coming years (assuming it’s possible) doesn’t mean particle beam weapons will prove effective as a means of missile defense. A great deal of testing will still be required before the Pentagon is confident such a satellite would work, but perhaps more important is that this endeavor could normalize the idea of weapons systems in space.

The Outer Space Treaty, ratified in 1967, bars the deployment of offensive weapons systems in space, though defensive platforms are widely considered to be acceptable. However, both China and Russia have begun deploying autonomous, maneuverable satellites that appear to be offensive orbital weapons that could interfere with orbital assets.