As the United States pushes forward with plans for a constellation of space-based interceptors (SBIs) designed to neutralize enemy missiles in their boost phase, a critical question is emerging: Who will protect the protectors? Experts are increasingly stressing that no matter their final configuration, these orbital weapons will require sophisticated defenses of their own—a crucial consideration often overlooked in discussions of requirements, capabilities, and costs.
The Imperative of Protection: A New Layer of Vulnerability
„It’s obviously very important that we find a way to develop this space layer in a protected way, not only from adversary kinetic or local orbital issues, but also from cyber attacks, electronic jamming and laser attacks,” Patrick Binning, a professor at the Johns Hopkins Whiting School of Engineering, emphasized during a webinar sponsored by Space News. He added, „We need to begin thinking about [defending] them, just as we are thinking about defending the rest of the space layer.”
The Trump administration’s „Golden Dome” missile defense shield, aimed at developing SBIs in low Earth orbit to target nuclear missiles from powers like Russia and China shortly after launch, is driving this new frontier. While the Space Force issued a request for prototype proposals in late September, the unclassified details remain private. However, as Breaking Defense first reported, pre-solicitation documents provided to industry outlined a Pentagon plan for companies to self-fund SBI prototype development under competing Other Transaction Authority contracts, with intercept tests slated for after 2028. Notably, these documents did not explicitly detail defenses for the SBIs themselves.
From Stealth to Lasers: Crafting SBI Defenses
According to Todd Harrison, a senior fellow at the American Enterprise Institute and co-author of a 2021 paper on satellite defenses, „Defense Against the Dark Arts in Space,” SBI defenses will need a multi-faceted approach. This includes passive measures like stealth technologies to make them harder to detect, either directly on the interceptors or integrated with larger support satellites. Active measures are also crucial, such as the ability to maneuver or the deployment of lasers to blind attacking satellites.
Harrison also pointed out a fascinating dual-use potential: „At the end of the day, you could actually expend an interceptor to take out an ASAT weapon… They can serve a dual purpose as anti-satellite defenders or anti-satellite weapons themselves.”
The Adversary’s Playbook: Decoys and Escalation Costs
However, adversaries won’t be idle. Harrison warns that the most efficient way for rivals to protect their missiles from SBIs would be to deploy a multitude of decoys. „[T]he number one thing they can do is just launch decoys… that cause us to expend our interceptors prematurely, and that would be the easiest way to make us lose interceptors and effectively poke a hole in the shield through which they could fire other missiles that now can’t be defended against,” he explained.
Todd Stevens, Lockheed Martin’s vice president for Strike, Deterrence & Missile Defense, concurred, though he suggested that the sheer number of SBIs expected to be orbited would likely make it difficult, and potentially expensive, for adversaries to severely damage the constellation. He believes that „whether it’s an interceptor or any other asset in space, there’s a need to have maneuver just like any other part of the military… and to be able to have some level of self protection included in it over time.”
Beyond Current Capabilities: Refueling and Rearming in Orbit
Binning, a former Pentagon Missile Defense Agency official, urged industry to explore „really advanced concepts” for SBI defenses. This includes the radical idea of re-fueling—and perhaps even „re-arming”—SBI systems in space, or after de-orbiting them. He noted that the interceptors, tipped with kinetic kill vehicles, would likely be housed on-orbit in „some type of support satellite” that „need to be re-fueled,” a concept already being considered by US Space Command.
Binning further proposed that the Defense Department consider re-arming these support satellites after they expend their on-board SBIs. „I think ideas along the lines of refueling the support satellite so it has more maneuver… we likely need, and [would like to see] the possibility of rearming that supports satellite as interceptors get used or get tested,” he stated.
The Decision-Making Conundrum: Architecture and Latency
Despite the technological advancements, a significant challenge lies in the command and control structure. Experts agree that the chain of command for critical decisions—such as the ultimate SBI architecture, the number of interceptors needed, deployment methods (individual or clustered), required kill probabilities, and the sophistication of the supporting command, control, and communications (C3) network—remains murky.
„The decision on the architecture starts with Gen. [Michael] Guetlein and his program office. He’s a direct report to the deputy secretary, and ultimately, this may be a White House decision,” Harrison noted, referring to Guetlein’s designation by President Donald Trump as the point person for „Golden Dome.” Harrison added that a prudent approach would involve „a process of development and prototyping to collect more data and then make a decision.”
Binning highlighted the critical issue of C3 latency, or data transmission time lag, particularly for the extremely short decision windows available during the boost phase (typically three to five minutes). More importantly, he stressed the need for established processes to ensure that authorized individuals can make crucial intercept decisions in time. „When it comes to latency, my concern is about the decision making and the government’s ability to say, ‘Yes, go conduct that intercept’,” he concluded, underscoring the immense pressure on human judgment in the age of orbital warfare.
