A 1984 artist’s concept of a ground/space-based hybrid laser weapon

Concept art: Air Force

This is part 4 of a 4-part special report on space-based interceptors. 

While much attention has been focused on renewed U.S. interest in potentially deploying space-based interceptors, another concept that emerged from President Ronald Reagan’s Strategic Defense Initiative in the 1980s is also being reexamined: putting lasers or neutral particle beams in space to shoot down enemy missiles.

“Directed energy to me is where we want to go in the long run,” Undersecretary of Defense for Research and Engineering Mike Griffin said in September during a roundtable on Capitol Hill. “We will be pushing advances in directed energy forward for the next few years.”

President Donald Trump’s fiscal year 2020 budget request for the Missile Defense Agency includes $304 million for technology maturation initiatives involving these types of technologies.

“Working with national laboratories and industry, MDA will address laser scaling by investing in the laser component technology required to demonstrate efficient electric lasers,” budget documents said. The agency plans to conduct component demonstrations to prove out laser capability.

The funding proposal also includes money for a neutral particle beam effort which will “design, develop and conduct a feasibility demonstration for a space-based directed energy intercept layer,” the documents said. “These efforts will leverage past and current work on particle beam and related enabling technologies as well as laser scaling, pointing and stability to provide a component technology to improve the cost-benefit and size, weight and power for an operational system.”

A future system of this kind would offer new “kill options” for the nation’s ballistic missile defense architecture and add another layer of protection for the homeland, the documents said.

Laser weapons use amplified beams of light to attack targets.

A neutral particle beam weapon would fire atomic particles at near-light speeds towards enemy platforms. The technology can be traced back to the Strategic Defense Initiative, Missile Defense Agency Deputy Director Rear Adm. Jon Hill noted.

“We think it’s got a lot of promise for the missile defense mission, and so our focus in FY ‘20 is to lay the foundation to get to an on-orbit demo” by 2023, he said during a briefing with reporters at the Pentagon when the budget proposal was rolled out.

The agency plans to conduct ground tests and demonstrations of neutral particle beam technologies with a focus on feasibility and maturing the technologies before they are put into space, Hill said.

Directed energy weapons would offer several benefits relative to kinetic interceptors, said Todd Harrison, director of the aerospace security project at the Center for Strategic and International Studies.

“You don’t have to worry about the time of flight … because the energy beam is going to travel at the speed of light,” he explained. “That gives you more time to identify a target and make the decision, and then fire; whereas with the kinetic interceptor you’ve got to fire very quickly because you have to take into account how long it’s going to take for your interceptor to fly towards the missile.”

Another advantage is that they could be reused to fire as many shots as their power systems would allow, he noted.

Fewer satellites would be required for missile defense if they were armed with directed energy weapons rather than kinetic interceptors, although the per system cost would likely be higher, he said.

Still fewer satellites would be needed if mirrors could be incorporated into the architecture, an idea which has been floated before, he noted. “With that you could only have a handful of really powerful lasers scattered around in orbit and then have more mirrors in other places that would reflect the light towards a missile” and destroy it.

But developing systems that could be used effectively in space is no easy task.

“You’ve got to have the powerful laser, you’ve got to miniaturize it, and then you have to have the power source on your satellite,” Harrison said. “All of those things are technical challenges.”

Employing mirrors would be another hurdle. “Obviously you don’t want it jittering or moving around and it has to be very precisely positioned” to hit the target, he added.

Directed energy technology is also not as mature as kinetic interceptor technology, he noted. “There’s a lot of work that still needs to be done if those systems are going to be fielded.”

But Griffin expressed confidence that an effective system could be created.

“I believe … we can develop space power systems that will provide what we need, but belief is an opinion held without benefit of facts,” he said. “It’s our job to go out and do the experiments and the prototyping to generate those facts.”