WASHINGTON — No matter what shape a future constellation of US space-based interceptors (SBI) takes, the orbital weapons will need to be protected, according to experts — a contention that has not been often included in speculation about requirements, capabilities and costs.
“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, told a webinar sponsored by Space News today.
“We need to begin thinking about [defending] them, just as we are thinking about defending the rest of the space layer,” he said.
The Trump administration is pursuing the development of SBIs in low Earth orbit to kill enemy nuclear missiles, including those of Russia and China, in their boost phase shortly after launch as part of the administration’s overarching Golden Dome missile defense shield. The Space Force on Sept. 25 issued a request for prototype proposal to industry that required responses by Oct. 2, but even the unclassified version of that request was not released to the public.
However, as first reported by Breaking Defense, pre-solicitation documents provided to industry laid out a Pentagon plan for companies to self-fund prototype SBI development under competing Other Transaction Authority contracts, culminating in an intercept test post-2028.
Those documents, however, didn’t mention defenses for the SBI’s themselves.
According to Todd Harrison, senior fellow at the American Enterprise Institute, defenses for SBIs will need to include both passive measures on-board the interceptors themselves or integrated with a larger support satellite, such as stealth technologies that would make them harder to detect, as well as active measures such as the capability to maneuver or lasers to blind attacking satellites.
There is also the potential for SBIs to in effect become anti-satellite (ASAT) weapons themselves, he added.
“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,” said Harrison, who co-authored a 2021 paper on satellite defenses, called “Defense Against the Dark Arts in Space.”
As for what adversaries could do to keep their missiles safe from SBIs, he noted that the most efficient way would simply be to deploy lots of lots 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,” Harrison said.
Todd Stevens, Lockheed Martin vice president for Strike, Deterrence & Missile Defense, agreed, even though he noted that the sheer number of SBIs expected to be orbited likely will make it difficult, and potentially expensive, for adversaries to severely damage or destroy the constellation.
“I think 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,” he said. “But for this particular layer … [we’re] gonna have to provide some sort of active measures I would suspect.”
Binning, who previously worked at the Pentagon’s Missile Defense Agency, said he would like industry to also look at “really advanced concepts” for SBI defenses, including re-fueling perhaps even “re-arming” the SBIs systems in space or on the ground after de-orbiting them.
Binning explained that the interceptors, tipped with kinetic kill vehicles to smash into the incoming missile, likely will be housed on-orbit in “some type of support satellite” that “need to be re-fueled” — something he noted that US Space Command already is thinking about.
But furthing, Binning suggested that the Defense Department consider the idea of re-arming the support satellites after they expend the 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 said.
Another area that remains murky, the experts agreed, is the chain of command for both making decisions about the ultimate SBI architecture — including how many interceptors will be needed, whether they will be deployed individually or in clusters aboard carrying satellites, what probability of kill each interceptor requires and how sophisticated the supporting command, control and communications (C3) network needs to be.
“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 said. Guetlein was named the point person for all things Golden Dome by President Donald Trump in March.
“I think that it’s a complicated decision tree in terms of what kind of architecture we’re going to acquire, what the specific requirements will be. And the truth is, they may not make all of those decisions right now, that they may — and this would be prudent actually — to go down a process of development and prototyping to collect more data and then make a decision,” he added.
Binning said one critical issue will be ensuring that the C3 structure will have the latency, or data transmission time lag, necessary to allow decisions in the very short windows available when trying to kill a missile in boost phase. Or, perhaps more importantly, he said it would be imperative to ensure that there are processes in place to ensure that the actual decisions can be taken by those authorized to do so in time.
“I think the issue is going to be in the decision-making. We’re only talking tens of minutes when these missiles are flying out in mid-course [defense], of course, the boost phase is only three to five minutes,” he said. “[W]hen it comes to latency, my concern is about the decision making and the government’s ability to say, ‘Yes, go conduct that intercept’.”