Like a cursed spell, space-based missile defense keeps getting resurrected — no matter how many times it’s been banished.
President Trump’s Executive Order, The Iron Dome for America, released Jan. 27, 2025, orders the Department of Defense to develop and deploy a “next-generation missile defense shield” — a system that would include space-based interceptors (SBI) to defend against ballistic missiles in their boost phase. Space-based missile defense was a key part of President Ronald Reagan’s Strategic Defense Initiative and has resurfaced intermittently ever since.
Once again, the United States is dreaming that it can shield itself from nuclear-armed missiles with an impenetrable defense. But it didn’t work then, and it won’t work now—and pretending otherwise will only fuel an arms race, weaken strategic stability, and divert resources from more effective defenses. , Instead, the U.S. is likely to end up with little real protection — while facing a wave of new threats. Unless this idea is dispelled once and for all, we will be doomed to repeat this dangerous cycle—at great cost and even greater risk.
Boost-phase missile defense targets a ballistic missile just after launch, when it’s still moving relatively slowly, is easily tracked by radar and hasn’t yet deployed decoys or countermeasures that complicate interception. But the window of opportunity is vanishingly short: for solid-fuel intercontinental ballistic missiles (ICBMs), there are mere minutes to detect the launch, track the target, fire an interceptor and score a hit. This necessitates the interceptors to be positioned nearby, which makes low Earth orbit (LEO) appealing.
On paper, it sounds promising. In practice, it simply doesn’t work.
As Laura Grego, research director and senior scientist for the Global Security Program at the Union of Concerned Scientists, has argued, the premise of a reliable shield against ICBMs is a fantasy. Sixty years and $350 billion have produced a system that at best is capable of intercepting a highly contrived test target 57% of the time, according to the U.S. Missile Defense Advocacy Alliance. But the problems of SBI extend beyond technical challenges: they’re baked into the laws of physics.
Ballistic missile interceptors stationed in space constantly circle the planet. That means thousands of satellites would be required to ensure that at least one is in position to intercept a missile during its brief boost phase.
A 2004 American Physical Society study found that, even under ideal conditions, 1,600 interceptors would be needed just to target a single ICBM from North Korea, Iran or Iraq. For context, China has an estimated 400 ICBMs, while Russia has about 326. And together, they span a landmass more than 12 times larger than North Korea, Iran and Iraq combined. The sheer scale of the challenge makes this system impractical at best and absurd at worst.
While proponents of the system cite declining launch costs as evidence of its feasibility, that’s only part of the story: the real cost lies in operating, maintaining and repairing a system that is inherently brittle. Not only must it function in a remote and harsh environment, but it is also vulnerable to being blinded, disabled, overwhelmed, hacked or circumvented far more easily than its advocates suggest, offering little protection under real-world conditions.
Conjuring an arms race
Far from enhancing security, SBIs are likely to increase global instability. President Trump claims they will provide “peace through strength,” echoing Reagan’s rhetoric. But history shows that chasing invulnerability only fuels arms races. Rival states won’t just counter these defenses — they will surpass them, investing in cheaper, more adaptable offensive technologies. Worse, they may feel pressured to strike preemptively before their nuclear deterrent is neutralized. Instead of reducing threats, space-based missile defense creates new ones.
The risks extend beyond security. Kinetic interceptions could generate hazardous space debris, threatening both military and civilian operations, not to mention risks to satellites in the line of fire.
Worse still, the U.S. would be giving up effective diplomatic tools for a sham capability. This year, the United Nations is launching a four-year initiative to prevent an arms race in outer space. For decades, SBIs have been a point of contention in arms control debates, with China and Russia advocating for a treaty banning space weapons, while others saw them as a distraction from more immediate threats like anti-satellite (ASAT) missile tests. If the specter of SBI moves closer to reality, there will be renewed international efforts to outlaw them. This effort could undermine U.S. leadership in space security, derail diplomatic initiatives to curb destructive ASAT missile tests and ultimately weaken efforts to promote responsible space behavior. The result would be a less secure and more dangerous space environment.
Beneath the technical, financial and geopolitical flaws of space-based missile defense lies a deeper issue: the myth of invulnerability. The idea that we can shield ourselves from catastrophic threats is not just unrealistic — it is dangerous. Real security doesn’t come from illusions of invulnerability, but from arms control, diplomacy and shared risk reduction.
Victoria Samson is Chief Director, Space Security and Stability at the Secure World Foundation, a U.S. operating foundation that promotes space sustainability, where she specializes in monitoring counterspace capabilities and multilateral space security discussions.
Jessica West is a CIGI Senior Fellow and a Senior Researcher at Project Ploughshares, a Canadian peace and security research institute, where she focuses on technology, security and governance in outer space.
SpaceNews is committed to publishing our community’s diverse perspectives. Whether you’re an academic, executive, engineer or even just a concerned citizen of the cosmos, send your arguments and viewpoints to opinion@spacenews.com to be considered for publication online or in our next magazine. The perspectives shared in these op-eds are solely those of the authors.
