Somewhere in the world, a missile’s engines ignite, and it lifts toward the sky. Somewhere above the world, satellites sense its launch. They, in turn, send out an alert, along with information about the missile’s path. Almost instantly an interceptor in orbit—essentially a big bullet—gets its own message: fire toward the missile. Ideally the space-based weapon strikes the missile early in flight, before the rocket can release a warhead or decoys, turning a threat to the U.S. into a bunch of debris.
Or at least that’s the idea behind space-based interceptors, the most audacious part of President Donald Trump’s Golden Dome missile-defense initiative to shield the U.S. from airborne attacks.
Much of the technology that could feed into Golden Dome already exists in pieces or inside other defense programs—it just (“just”) needs to be linked together and scaled until it can protect the entire country around the clock. Space-based interceptors, though, don’t yet exist as an operational system. And there isn’t a firm plan for what they will look like—or, for that matter, what Golden Dome as a whole will look like. As Todd Harrison, a senior fellow at the American Enterprise Institute, puts it, “There is no architecture,” at least not one that’s been released publicly. That fuzziness, however, isn’t stopping American companies from preparing to make orbital interceptors in the hopes of cashing in on the most speculative and, by some accounts, expensive part of the defense project.
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One such hopeful is Voyager Technologies. Voyager got its start working on NASA projects related to the moon and space stations. “About two years ago we had started doing some investments in the defense and national security side of the business,” says Matt Magaña, Voyager’s president of space, defense and national security. Those investments involved, in part, buying up other companies that had already developed space tech that could prove useful for Golden Dome—including radiation-hardened electronics, electric propulsion systems that allow satellites to make precise movements, and solid-fuel rocket systems that might let interceptors maneuver quickly in pursuit of a missile.
When Voyager started that shopping spree, Golden Dome hadn’t yet been announced. But the trajectory worked out, in part because defense is defense: The company was already working, for instance, on the next generation of ground-based interceptors—a replacement for a system that already exists. Its inner workings are not that different from the orbiting-interceptor plans, Harrison says: find a missile, figure out where it’s going, figure out where you can intersect with it—boom.
On top of that, defending the country from space had been a national security aspiration for years—decades, even—before Golden Dome existed. So when Golden Dome and its space components became a thing, Voyager was ready. “A lot of that fits exactly square on where we’ve been investing and where we have tech,” Magaña says.
But space-based interceptors do require something new, Harrison says: scale. A threatening missile could theoretically launch from anywhere in the world, which means Golden Dome would need enough orbital interceptors to cover possible launch points around the planet—ideally with more than one shot at each threat. According to one of Harrison’s analyses, “approximately 1,900 interceptors would be needed to provide continuous coverage of all points on Earth with an average of two interceptors” because the first try might miss.
That thousands-strong system would not be built to stop a large strike from Russia or China.
That estimate assumes coverage for one incoming missile. A real attacker would probably launch a salvo, hoping to overwhelm Golden Dome’s defenses. “It’s a numbers game,” says Victoria Samson, chief director of space security and stability at the Secure World Foundation. In a recent report, the Congressional Budget Office (CBO) ran the numbers on a less forgiving scenario and found that a space-based system would require around 7,800 interceptor satellites just to stand up to a minor adversary or a small attack from a more significant one: 10 intercontinental ballistic missiles launched nearly at once. But that thousands-strong system would not be built to stop a large strike from Russia or China.
On top of that, the entire sequence has to happen quickly. Many of the envisioned interceptors are supposed to hit the missile while it’s still in its “boost” phase, when its engines are firing. That way, Harrison says, the interceptors strike while the threat is farther away and before it can send out decoys.
But that golden window isn’t an hour; it’s minutes. “So that’s just a short amount of time to be able to identify that something’s been launched, recognize that it’s a threat and then make the decision to try to intercept it,” Samson says. Only then can the system tell the interceptor what to do. The scale and timing problems help to explain why space-based missile defense has stayed mostly aspirational since President Ronald Reagan’s Strategic Defense Initiative, aka Star Wars, which was announced in 1983.
There are also complications beyond the hardware. This part of Golden Dome means putting interceptors in orbit, something the U.S. has never done. “I think we’re crossing a red line,” Samson says. If the U.S. does it, others may do the same. Putting weapons in space means more chances for orbital attacks and accidental collisions in orbit, both of which would create space debris that could take out other important satellites or fall back to Earth. And the U.S., a country very reliant on satellites and space infrastructure, has the most to lose.
No one knows exactly what that space-based system will look like. But the Department of Defense is nonetheless trying to make sure companies are ready to build it. That’s why this past April, Space Force’s acquisition arm awarded agreements worth up to $3.2 billion to 12 companies. Anduril is one of the awardees, and Voyager is part of its team. Other recipients are Lockheed Martin, Northrop Grumman, Raytheon and Booz Allen Hamilton. These contracts may indeed help mature the technology, Harrison says, but they don’t help with the biggest hurdle: scale, which means building thousands of interceptors and getting them to work as one system.
Despite that gap, the Trump administration has said it wants to demonstrate an integrated space-based interceptor capability by 2028—not far away and during a U.S. presidential election year. “I have a feeling we will test something just to be able to say we checked that box,” Samson says.
Voyager is trying to keep its eye on the scale problem. For instance, it recently announced two huge facilities: one in Long Beach, Calif., focused on advanced satellite electronics, and another in southern Colorado focused on propulsion for weapons systems. Together they approach 300,000 square feet. It’s a good bet that Golden Dome and related defense programs will need the kind of space hardware Voyager has been trying to assemble.
The company is not alone in that kind of positioning. “Starting last summer, I felt like I started seeing news stories where companies were like, ‘Hey, we have this capability. We could definitely prove we could do this,’ ” Samson says. “And it wasn’t just the major primes like Lockheed Martin—it was smaller, new space actors.” She’s even seen companies plying their wares as great “targets” for future interceptor tests. “Basically everyone’s scrambling to get a piece of Golden Dome funding,” she says.
The money at stake is potentially enormous. The administration said in March that Golden Dome will cost $185 billion. Harrison, meanwhile, has calculated that it might cost up to $3.6 trillion. The CBO lands between those numbers in its report, estimating $1.2 trillion over 20 years, with space-based interceptors accounting for 60 percent of the total.
In Harrison’s view, it’ll be a good long while before anyone knows how many thousands of interceptors will be in orbit or how they’ll mesh with the rest of the dome. By the time the architecture is even set, he says, Golden Dome will probably have changed forms, been canceled and been resurrected with a different name.
It may not even have space-based interceptors in the future, Samson says. But missile defense is not going anywhere—so the technology that Voyager and other space start-ups are working on, alongside the traditional defense giants, is likely to remain applicable and profitable. “You cannot get rid of it,” she says.