In early May 2026, the Congressional Budget Office (CBO) reported a cost estimate of $1.2 trillion for the Golden Dome for America homeland missile defense system. This stood in sharp contrast to the estimate that Pentagon senior officials provided to the House’s Subcommittee on Strategic Forces in April—$185 billion. The CBO report stated that even at the $1.2 trillion estimate, the resulting system “would not … be able to fully counter a large attack of the sort that Russia or China might be able to launch.” When asked about the budget office’s higher cost estimates, the program director of Golden Dome, General Michael Guetlein, responded that “[the CBO] is not estimating what I’m building.”
This level of misalignment across defense budget decision makers is highly unusual and while many aspects surrounding Golden Dome remain unclear, one thing is certain: If the program is to have a productive future, the Department of Defense, Congress, and the broader administration will need to get on the same page quickly.
Improved US homeland missile defense is needed
Driving the need for Golden Dome is the emergence of highly maneuverable, next-generation weapon systems—such as hypersonic missiles, advanced cruise missiles, and intercontinental ballistic missiles—which Russia and China are actively fielding. The fact that the United States possesses a very limited number of missile defense interceptors protecting the homeland adds to the sense of urgency. US territory is currently protected from intercontinental ballistic missile attack by the Ground-Based Midcourse Defense System. The Missile Defense Agency, which currently receives approximately ten billion dollars a year, developed the system, activated the system in 2004, and has ongoing programs to upgrade its technology. The Ground-Based Midcourse Defense System connects overhead satellite missile warning systems to radars and long-range interceptors. It stands watch against incoming missiles 24/7 and has forty-four missile interceptors deployed to Fort Greely in Alaska and Vandenberg Space Force Base in California. While the interceptors have a continent-wide engagement capability, the limited fleet would be overwhelmed by an attack of even moderate scale. As Guetlein reported in his prepared statement to the House subcommittee on April 15:
- “Adversaries are rapidly modernizing their militaries and seek to erode our advantages to hold the United States at risk. New and emerging technologies create opportunities for attacks on the American homeland. Near-peer competitors and rogue states are aggressively developing and fielding advanced conventional and nuclear-capable missiles designed to evade or overwhelm our existing defenses.”
Interceptors in space
The executive order that initiated the Golden Dome for America program mandated the “development and deployment of proliferated space-based interceptors” as a major new element of the missile defense architecture. Ever since President Ronald Reagan’s so-called Star Wars initiative, space-based interceptors (SBIs) have periodically captured the imagination of missile defense experts as a potential breakthrough capability in the missile defense arsenal. However, the Golden Dome SBIs represent the largest source of cost disparity between the Pentagon and the CBO figures‚ as they amount to approximately 70 percent of the CBO’s total cost figure. The April 2026 award of $3.2 billion to twelve companies to move forward with concept development and demonstrations of SBIs has captured the defense industry’s attention and spawned a multitude of concepts.
The appeal of space-based interceptors lies in their potential to open up an entirely new layer of missile defense. Current Ground-Based Midcourse systems intercept missile warheads after the warheads have separated from their thrusting missile and are cruising above the atmosphere in what is called midcourse. During midcourse flight, an enemy missile has completed rocket flight and deployed its warheads—along with any decoys and countermeasures it has—making for a complex job for the interceptor to identify and target the warheads. Space-based interceptors distributed across low-earth orbits could potentially be in the right place at the right time to reach the incoming missiles early in flight, before the warheads have had a chance to separate, in what is called boost stage. At this point in flight, the missile is still burning its rocket engines, is easily tracked, and is a single obvious target. Space-based interceptors could also augment the limited number of Ground-Based Midcourse Defense System interceptors by performing intercepts during midcourse flight.
Thousands of space-based interceptors
To be effective against an attack of fifty to one hundred missiles, thousands or tens of thousands of SBIs would be needed, amounting to a potentially withering total cost. With each SBI constantly circling the globe in low-earth orbit, very few of them would be near a specific missile launch area when the missile was fired. For the system to be effective, enough interceptors would need to be constantly passing over the initial flight path of every potential attacking missile across the world, requiring thousands of space-based interceptors spread out across the entirety of low-earth orbit.
Also, more than one interceptor is typically fired at any given threat, compounding the problem. The CBO estimates that nearly eight thousand space-based interceptors would be needed to provide boost stage defense against a mere ten enemy missiles. Senior fellow at the American Enterprise Institute Todd Harrison studied a series of candidate missile defense architectures and his conclusions for the magnitude of SBIs needed to be effective were generally consistent with the CBO’s report.
How well can space-based interceptors be defended?
Beyond the shear numbers of SBIs that may be needed, planners must also tackle the question of how the interceptors themselves would be defended in space. The Space Force is currently grappling with similar issues as it considers approaches to protect the extensive US fleet of military and intelligence satellites. In response to this concern, the president’s Space Force budget request for 2027 includes $71 billion, a 40 percent increase over 2026, of which $22 billion is specifically provided for “space control,” which provides security in space for operations.
Current land- and sea-based interceptors are protected in silos on US bases or on Navy ships, but space-based interceptors will be exposed. They will travel very predictably, over adversaries approximately every ninety minutes, and will routinely orbit near to other, potentially hostile, satellites. Unlike Navy ships on patrol, for an orbiting spacecraft, there is no safe harbor. China and Russia are working hard to exploit this weakness and have been demonstrating anti-satellite weapons including ground-based anti-satellite missiles, lasers, jammers, and similar space-based weapons. There are even reports that Russia has been developing a space-based nuclear weapon. As General B. Chance Saltzman, the US commander of space operations (CSO), said in a December 2025 interview: “In a word, the threat landscape since I took over as CSO has advanced dramatically.”
The critical need for space asset defense is currently motivating the creation of a veritable US space armada to alert and defend satellites from encroaching threats. Major technological advances to improve the resilience of satellite constellations are underway with advances in construction, mobility, and countermeasures for what today are relatively, static, fragile devices. As the offensive military space capabilities of adversaries grow and even rogue states gain space capabilities, the nagging question remains: How effectively will the United States be able to protect critical satellite infrastructure, how much will it cost to do so, and how should that guide future investment, specifically in the future missile defense architecture? This topic and the associated cost are absent from the CBO estimate altogether.
The decisions and challenges ahead
As Golden Dome moves forward, the team is no doubt considering the successes and challenges of the large missile defense programs of the late 1990s and early 2000s, their parallels to Golden Dome, and the lessons learned. One common lesson is the failure to minimize organizational complexity. The fast-paced Golden Dome program will be challenged to spend its large budget efficiently.
With many government stakeholders, a multitude of potential industry suppliers, government laboratories, and Systems Engineering and Technical Assistance contractors, all vying to participate in some manner there is no shortage of ways to spend the money. However, Guetlein should consider Conway’s Law, which states that the structure of a system will reflect the structure of the organization that built it. The more complex the organization, the more complex and costly the system. Key advances are typically accomplished by small empowered teams working with agility. In contrast, the missile defense programs of the early 2000s arguably employed more reviewers than doers, slowing them down and driving cost. If the program is to survive multiple budget cycles and administrations, Golden Dome will require an efficient, lean organization and a development approach that demonstrates incremental progress along the way.
Whether the right estimate for Golden Dome is $185 billion or $1.2 trillion, it would be an unconscionable waste for the program to rush to the wrong answers. Guetlein and his team are no doubt deep into massive trades of technologies, capabilities, costs, risks, and schedules, all in a world of evolving missile threats. Simultaneously, valuable lessons are being learned about the economics of missile defense over the skies of the Middle East. The results of these assessments will guide generational decisions on how much resources will be put toward enhancing existing systems with more and better interceptors and improved sensors, how much will be spent on expanding into space with space-based interceptors, and what bets will be placed on introducing new revolutionary technologies, such as directed energy approaches.
In the scope of this enormous task, the administration has set an aggressive, 2028 election cycle deadline for a Golden Dome “operational capability.” While advanced technology demonstrations and upgrades to current systems are achievable and necessary in this timeframe, a deployed operational capability of a new strategic system for homeland missile defense is almost certainly not. This artificial deadline risks forcing decisions that may undermine the selection of the best architecture to support future US missile defense needs. Therefore, it is paramount that the Pentagon and Congress come to agreement on a schedule of milestones for this monumental program, with the first and immediate milestone being to agree on the objective capability of Golden Dome and an affordable cost.