Here’s the role that space-based interceptors will play in Golden Dome

Space-based interceptors (SBIs) are poised to become reality through Golden Dome for America, a once-in-a-generation missile defense initiative announced via executive order earlier this year. An innovative concept first developed as part of President Reagan’s Strategic Defense Initiative (SDI), Golden Dome will field for the first time an integrated network of SBIs as part of an orbital system designed to defend against ballistic and hypersonic missiles.

Northrop Grumman has led the way on SBIs since the 1980s — the company was the prime contractor for the SBI component of SDI — and is currently developing and testing SBI technology. We caught up with Michelle Mathieson, SBI lead at Northrop Grumman, to learn about SBIs and how Northrop Grumman is bringing this technology to Golden Dome.

Breaking Defense: What are SBIs, in the simplest terms?

Mathieson: SBIs are interceptors launched from space from orbiting satellites — the ultimate “Eagles Nest” over Earth. Today, the U.S. has interceptors that can be launched from land, sea and air to defeat a missile threat during the middle or final phases of its path toward its intended target. SBIs could defeat a missile threat earlier in its flight.

What would an SBI mission look like and how would SBIs be deployed?

SBIs expand America’s intercept capability into another warfighting domain: space. They will be the new ‘first up’ in our nation’s missile defense architecture — the first to see, engage and intercept the threat.

Space sensors would communicate early warning of an adversary missile launch, working with integrated command and control systems to detect and track the threat, as well as develop a plan to intercept — all in a matter of seconds. This would be validated and securely communicated to strategically positioned SBIs orbiting Earth. If the command is given, SBIs could intercept the adversary missile early in its path.

What are the advantages of SBIs compared to other interceptors?

First, I’ll underscore that, ideally, the missile never launches in the first place and Golden Dome will expand capabilities to prevent and disrupt adversary launches.

If a missile does launch, the sooner it can be stopped, the better. Compared to our current intercept capabilities, SBIs engage in less time with less energy, and intercept closer to our adversaries’ launch sites.

The key advantage of SBIs is they can defeat missile threats earlier in their trajectory than today’s interceptors. Intercepting during early flight eliminates the threat furthest from the homeland and prevents the missile from releasing additional threats and decoys during its path.

SBIs also have an edge from a physics perspective. Because they’re in space, they don’t have to fight against gravity to launch like interceptors launched terrestrially. This means they would need less fuel to launch, allowing for a more compact interceptor.

How does Northrop Grumman envision SBIs fitting into the overall Golden Dome architecture?

When it comes to missile defeat, there’s no single solution that can address every threat. Instead, Golden Dome is a layered, integrated architecture, with each layer playing its part to eliminate all threats. We see SBIs as a critical piece of the Golden Dome architecture that not only mitigates threats early in their trajectory but also improves performance of the entire Golden Dome.

For example, if a volley of multiple missiles is launched, SBIs would be the first line of defense, taking out as many missile threats as possible, as early as possible. In addition to SBIs targeting threats in their boost phase, they will continue striking missiles in the middle of their trajectory alongside land- or sea-based interceptors, such as Glide Phase Interceptors for hypersonic threats. Then, if needed, regional defense will eliminate the remaining threats in the final phase of their path — so that nothing gets through to the homeland.

What will be critical to fielding SBIs?

SBIs will need access to fused data from space-based missile warning and tracking systems, like Next-Gen OPIR Polar and the Space Development Agency’s Proliferated Warfighter Space Architecture Tracking Layer, both of which Northrop Grumman is developing. SBIs will then need to quickly fire interceptors based on that information.

Manufacturing capacity will also be critical. SBIs, like all interceptors, will require reliable propulsion. As the world’s leading solid rocket motor (SRM) producer, Northrop Grumman has invested over $1 billion in SRM manufacturing capacity since 2018. We stand ready to meet the nation’s needs for solid rockets for its interceptors, whether launched from land, sea, air or space.

Finally, mission understanding will be key not only for SBIs but for Golden Dome overall. Northrop Grumman has enabled the missile defense mission for decades, with a portfolio spanning from left of launch to terminal-phase defeat — just like Golden Dome will. In fact, we’ve been developing SBI technology since the 1980s and TRW, one of our legacy companies, was the prime contractor for the SBI component of Reagan’s Strategic Defense Initiative. We see SBIs as a critical homeland defense layer, and we are taking action today to deliver on this needed, emerging capability.