Ramin Skibba is an astrophysicist turned science writer and freelance journalist based in San Diego. He has written for The Atlantic, Slate, National Geographic, Scientific American, and Nature, among other publications. He can be found at raminskibba.net and on Twitter at @raminskibba.

“When it comes to defending America, it is not enough to merely have an American presence in space,” President Donald Trump said Monday as he announced the creation of a new “Space Force” to protect U.S. interests and assets in space. “We must have American dominance in space.”

Past American presidents may have thought the same, and acted accordingly, but rarely have they ever expressed this sentiment so brazenly. It’s yet another way Trump has broken with past precedent—and it could set off a dangerous arms race, potentially sparking a Cold War in space.


As one top expert on space security, Joan Johnson-Freese of the U.S. Naval War College in Newport, Rhode Island, put it to me, “This will probably be seen as another indicator that the United States is moving towards a more militaristic position regarding space activity.”

Trump directed the Pentagon on Monday to establish a sixth branch of the military to focus on space, presumably separating personnel that concentrate on things like military satellites and their ground infrastructure from the Air Force. Though he called American “destiny” in space “a matter of national security,” the president didn’t say anything specific about whether the Space Force will simply be continuing U.S. Air Force activities, or whether it would be launching new ones, such as developing offensive or defensive weapons capabilities. A separate plan for developing missile defense platforms to be deployed in space may be in the works as well, though, if Congress decides to fund it.

Advocates of militarizing space are thrilled, but Trump’s move threatens to antagonize the U.S.’s biggest rivals in space, China and Russia. Each have hundreds of satellites of their own, and if they see the U.S. taking a more muscular posture in the cosmos, they’ll likely boost their corresponding budgets, possibly including studying how to shoot down or hack American satellites or spacecraft.

For decades, diplomats have tried to prevent exactly this scenario. International space law, first established by the Outer Space Treaty in 1967, which the U.S. has signed, sees outer space—low Earth orbit and beyond—as a public good to be protected. Like Antarctica, people may travel there and scientists may conduct research, but it’s not viewed as a potential battlefield. “There are significant restrictions on what the military can do,” said Joanne Gabrynowicz, a space law expert at the University of Mississippi who is also editor-in-chief emerita of the Journal of Space Law. The 51-year-old treaty prohibits launching weapons of mass destruction, like nuclear weapons, into space, and it prohibits military bases and maneuvers on the moon. It also says the use of outer space should maintain international peace and security and promote international cooperation and understanding.

The treaty is silent about less destructive weapons in open space, say, missile defense systems or non-nuclear attack weapons, but a set of taboos has tended to govern their use. The United States and other space powers have avoided using space for military purposes, refraining from launching or testing space weapons and from equipping satellites with weapons.

Trump, though, seems to be pulling away from current norms. In March, at the Marine Corps Air Station Miramar near San Diego, he called space “a warfighting domain just like the land, the air and sea.” Vice President Pence, chairman of the National Space Council, has sounded similarly militaristic, writing in March that the moon was a “vital strategic goal” and that “America must be as dominant in the heavens as it is on Earth.”

The justification for the administration’s new space focus seems to be at least partly that China and Russia have been secretly at work on their own space-based military capabilities. “Our adversaries are aggressively developing jamming and hacking capabilities that could cripple critical military surveillance, navigation systems and communication networks,” Pence wrote. Experts say it’s impossible to know whether that is true. But one thing they do agree on: Once the U.S. has sent weapons into space, other countries will follow—blowing up traditional norms and turning low Earth orbit into a dangerous place.

That fear isn’t just limited to Space Force, which might not make it very far. The proposal resurrects a similar idea for a “space corps,” which was championed by House Armed Services Committee Chairman Mac Thornberry (R-Texas) and strategic forces subcommittee Chairman Mike Rogers (R-Ala.). The space corps failed to make it into the National Defense Authorization Act last year, and the congressional opposition that killed it remains. So does skepticism within the upper echelons of the Defense Department: Defense Secretary Jim Mattis himself opposed the idea last year, calling it premature to add new bureaucracy to the department. The Space Force similarly could be quashed if both houses of Congress aren’t on board.

But there are other plans to militarize space that don’t involve a new military branch. A separate proposal to develop space-based missile defense systems, advocated by Senator Ted Cruz (R-Texas) and other Congress members, did find its way into last year’s authorization bill. If such systems are included in the Pentagon’s Missile Defense Review, whose release has been delayed by months, then it would mean that there is sufficient support for them for the military to receive funding to develop the technology and eventually test it.

“Allies and adversaries alike would see putting interceptors in space as the first time anyone’s put dedicated destructive weapons up there. If you’re concerned about keeping space secure and usable, it would be crossing a line,” said Laura Grego, a Caltech-trained physicist and senior scientist of the Union of Concerned Scientists.

This all for a system of questionable effectiveness. Missile defense systems either need to take long-range missiles out in the brief boost phase or contend with missile countermeasures like decoys and balloons later. Either way, such systems have had a spotty track record in tests so far. Plus, orbiting weapons travel at some 17,000 miles per hour and quickly move out of range, meaning that hundreds or more missile defense systems would be needed to make them worthwhile. Constructing so many systems and sending them out into space would make the costs add up rapidly. Interceptors launched from the ground or ships or even laser-firing drones hovering at low altitude can be much more effective.

The fear, though, is that missile interceptors are much better offensive than defensive weapons—offensive weapons targeting satellites, Grego told me. A sky full of Chinese and Russian missile defense systems, she said, would be a serious threat to the more than 500 U.S. satellites currently in orbit, which enable everything from GPS to communications and weather forecasting.

If the U.S. missile defense proposal moves forward, it could be the beginning of a full-scale satellite war. “My biggest concern is that [the U.S.] would do a test bed, to demonstrate that it works. There’s no formal agreement, but there’s an unspoken consensus prohibiting weapons in space. The point of the test bed is to break that taboo,” said George N. Lewis, a physicist and a visiting scholar at Cornell University.

A test of a space-based interceptor or laser system might seem far-fetched, but it too, was explicitly included in last year’s authorization act. And then if China, for example, felt threatened by such a test, it could demonstrate its own weapons. In 2007, China tested an antisatellite missile launched from the ground, which created more debris in an already crowded orbit, threatening other satellites.

Once the taboo on space-based weapons is broken, suddenly anything in orbit that can maneuver could be turned into a space weapon. Government or private owners of crucial billion-dollar satellites could feel threatened, such as if a rival’s weapon system parked in orbit in range, risking a Cuban missile crisis 300 miles above the ground.

In that case, an effort to increase security would have actually undermined it.

Trump says he wants American domination in space, but “what does that mean, to ‘dominate’?” Johnson-Freese, the space security expert, asked. “We already had that rhetoric under the George W. Bush administration. Now it’s being revived, and it probably will have the same kind of negative unintended consequences.”