In a 2017 live-fire demonstration at the U.S. Army's White Sands Missile Range in New Mexico, a 30-kilowatt class laser weapon system developed by Lockheed Martin brought down five unmanned aerial vehicles with a 100 percent success rate. Credit: Lockheed Martin

This op-ed originally appeared in the June 10, 2019 issue of SpaceNews magazine.

When it comes to destroying anti-satellite missiles in time to keep their debris out of orbit, as well as removing tiny pieces of space junk already there, space-based lasers are the only practical technology. The catch? Only small space nuclear reactors can provide the power necessary to operate these lasers. Small terrestrial nuclear reactors are also the answer to reliably meeting growing energy needs without polluting the atmosphere. For the benefit of the Earth’s orbit and atmosphere, the time has come to embrace small nuclear reactors.

Experimental laser weapons have been fielded for decades, but the enabling technologies and threats that make them practical in battle have matured considerably in recent years. Lockheed Martin, for example, internally funded a mobile laser recently to deal with the increasing threat of weaponized drones.

NASA intends to test the Laser Communications Relay Demonstration payload aboard the U.S. Air Force’s STPSat 6 satellite slated to launch geosynchronous orbit later this year. Credit: NASA Goddard
NASA intends to test the Laser Communications Relay Demonstration payload aboard the U.S. Air Force’s STPSat 6 satellite slated to launch geosynchronous orbit later this year. Credit: NASA Goddard

For anti-satellite and ballistic missile defense, the key advantage lasers have over kinetic systems is that they can strike missiles in their vulnerable boost phase. Basing lasers in space improves on this advantage because there is less atmosphere between the laser and its targets, increasing effective range and accuracy. Space-based lasers may also be the best way to confront the new hypersonic threats because their beams can instantly adjust to rapidly changing target trajectories.

Space-based lasers have a number of important commercial uses now and in the near future. They can provide high-bandwidth, secure communications from space. NASA will demonstrate this capability in 2020. Space-based lasers will also become more important for quantum key distribution, needed to counter the threat quantum computers pose to conventional cryptographic security.

Unlike kinetic systems, a single laser can take out multiple targets. Solar panels, however, are not able to sustain continuous operation of high-power lasers. Small space nuclear reactors solve this problem, as they offer a nearly inexhaustible supply of multimegawatt power. Space reactors are also more compact and sturdy than solar arrays, able to support quick tactical maneuvers. NASA also needs reactors for deep space exploration and manned missions to Mars. The main problem in realizing the full benefits of space-based lasers is the unavailability of space nuclear reactors, which is mostly due to the stigma and political risk that still surrounds nuclear power in general.

Space nuclear power is not fanciful technology. The U.S. has launched into space 32 radioisotope generators and one reactor since 1961. From 1967 to 1988, the Soviet Union fielded 35 space reactors. In the 1980s, U.S. Strategic Defense Initiative (SDI) development of space reactors employed many researchers, including myself, because it was seen as the only practical way to power space-based lasers and other directed energy weapons. We even borrowed one of Russia’s space reactors so we could study it for SDI applications.

Small reactor technology, like that needed to support space-based laser weapons, will be key to the U.S. winning the nuclear energy export race and maintaining its preeminence in nuclear science and engineering. They are easier to finance than the normal gigawatt-scale reactors costing billions. And fielded as expeditionary power sources for military operations, small reactors are less expensive over the long term and can save lives by avoiding the dangers of transporting petroleum in or near a battlefield.

A rendering of a small modular reactor under development by NuScale Power, an Oregon company seeking to commercialize a reactor capable of producing 60 megawatts of electricity using a novel cooling design. This reactor is 20 meters high with a diameter of 2.7 meters. Credit: NuScale Power LLC

Nuclear power is also the only realistic solution to the carbon dioxide waste problem. Except for hydroelectric power, nuclear reactors have the smallest greenhouse gas footprint of all energy-producing technology, including photovoltaics and wind. Furthermore, the health and environmental dangers of extremely rare reactor accidents are small compared to the normal operation of fossil fuel plants that dump billions of tons of carbon dioxide into the biosphere annually. Space reactors can be launched “cold and clean,” becoming radioactive only after being inserted into a safe long-term orbit.

A vibrant nuclear energy sector, aided by small reactors, will help avoid future military confrontations arising due to a reliance on fossil fuels. Small and micro-sized groundbased reactors can also contribute to decentralizing electricity-generation markets and help harden the grid against cyber threats. Recent government and private sector investments in small reactor designs like NuScale and eVinci should, therefore, contribute to both national security and the economy.

The civil applications of space-based lasers and small reactors will of course differ in many ways from their military counterparts, but the underlying physics and enabling technologies are the same. Investments in one will help the other. Following the model that worked so well for GPS and the internet, the Defense Department should begin by fielding early working systems, demonstrate their effectiveness and safety, and then open them up to the commercial sector. These endeavors will also lessen the stigma and political risk of nuclear power and help usher in a new era of high-power space technology.

Vaughn Standley is the Department of Energy Faculty Chair at the National Defense University’s College of Information and Cyberspace. The opinions expressed are those of the author and do not necessarily reflect the views of the Department of Defense or any other federal agency.