Golden Dome and the Cost of a National Missile Defense System

Key Takeaways

• CBO estimated a 20-year cost near $1.2 trillion for its notional missile defense system.
• Space-based interceptors drive most of the projected acquisition and lifetime cost.
• Golden Dome’s final cost depends on architecture, coverage, capacity, and funding choices.

CBO’s National Missile Defense Cost Estimate

The Congressional Budget Office estimated in May 2026 that a national missile defense system broadly consistent with the January 2025 Iron Dome for America executive order would cost about $1.2 trillion to develop, deploy, and operate over 20 years, measured in 2026 dollars. That estimate does not describe a confirmed Department of Defense deployment plan. It describes CBO’s notional architecture, built from the capabilities named in the executive order and from public information about missile defense systems, space sensors, interceptors, and supporting command networks.

The distinction matters. Golden Dome for America is an active Department of Defense initiative, but CBO reported that the department had not released enough information about the final “objective architecture” to support a direct long-term estimate. The public budget material available for fiscal year 2027 showed near-term funding plans, not the full number of sites, satellites, interceptors, sensors, communications elements, and operating units that would define a completed system.

CBO’s notional design gives policymakers a cost model rather than a final program bill. It assumes a layered defense with space-based interceptors, two wide-area surface layers, regional terminal-defense sectors, space-based missile tracking, and research, development, test, and evaluation funding for integration and improvement. Acquisition accounts for just over $1 trillion of the estimate. Operating and support costs add roughly $8.3 billion per year once the system’s components enter service.

The system is designed around defense against ballistic missiles, hypersonic missiles, cruise missiles, and other aerial threats. It covers the United States, including Alaska and Hawaii, and includes enough capacity to engage a regional adversary’s limited attack or a small attack from a larger military power. CBO does not present the system as an impenetrable shield. A large-scale attack by Russia or China could overwhelm the architecture. That limitation shapes the article’s core point: Golden Dome is not a single procurement decision, but a set of architecture choices that trade cost, coverage, capacity, and strategic risk.

CBO’s cost structure also shows why the debate over Golden Dome differs from earlier missile defense debates. The largest cost driver is not the familiar ground-based interceptor field. It is the proposed space-based interceptor layer, a large satellite constellation designed to engage missiles during boost phase, when a missile’s rocket motor is still burning.

The following table summarizes the largest cost components in CBO’s notional architecture.

What the Golden Dome Order Asked DoD to Build

The executive order behind Golden Dome called for a next-generation missile defense shield to deter and defend against foreign aerial attack on the U.S. homeland. It named ballistic missiles, hypersonic weapons, advanced cruise missiles, and other next-generation aerial attacks. It also directed the Secretary of Defense to develop plans involving space-based interceptors, missile warning, tracking, and multiple layers of defense.

CBO grouped those requirements into three design characteristics: comprehensiveness, capacity, and coverage. Comprehensiveness means the system must address more than one missile type. Capacity means it must handle more than a single incoming missile. Coverage means it must protect population centers and infrastructure across the United States rather than only a few military sites.

Those three characteristics push the architecture toward high cost. A defense that protects one location against a small number of ballistic missiles can be much smaller. A defense that covers the continental United States, Alaska, and Hawaii against ballistic missiles, hypersonic glide vehicles, and cruise missiles needs sensors, interceptors, command systems, and operators distributed across many locations and orbits. Geography becomes a cost driver because coverage must account for missile approach paths, regional population distribution, radar placement, and the physical limits of interceptor reach.

The executive order also called for space-based interceptors. That requirement separates Golden Dome from missile defense architectures that rely mainly on ground-based interceptors and sensors. Space-based interceptors are attractive in concept because they could attack some missiles during boost phase. A successful boost-phase intercept happens early, before warheads, decoys, or other penetration aids separate. The physics are difficult because the window lasts only minutes and the interceptor must already be close enough to reach the threat in time.

The surface layers address later parts of flight. The upper wide-area surface layer uses interceptors designed for midcourse defense, when a ballistic missile warhead travels outside the atmosphere. The lower wide-area surface layer uses Aegis Ashore-type facilities with Standard Missile interceptors. Regional sectors provide terminal defense, meaning they try to engage threats closer to defended areas. The complete system also needs space-based tracking because missile defense depends on early detection, accurate tracking, and fast command decisions.

Golden Dome’s policy design is broader than Israel’s Iron Dome, despite the similar name. Iron Dome is a short-range air defense system built for rockets, artillery shells, and some drones. Golden Dome, as described in U.S. policy and CBO’s cost model, concerns homeland-scale defense against long-range ballistic missiles, hypersonic glide vehicles, cruise missiles, and other threats. The name may be politically useful, but the technical and budgetary problem is much larger.

Why Space-Based Interceptors Dominate the Cost

Space-based interceptors account for about 70 percent of acquisition cost and roughly 60 percent of the total 20-year cost in CBO’s notional architecture. CBO modeled a constellation of 7,800 satellites in nearly polar low Earth orbit, sized to engage a raid of 10 nearly simultaneous intercontinental ballistic missiles. The model assumes two interceptor shots per target to improve the probability of a successful engagement.

The constellation’s size comes from orbital mechanics rather than bureaucratic excess. A satellite in low Earth orbit moves quickly across Earth’s surface. It cannot hover above one missile launch region unless it sits in geostationary orbit, which is far too distant for boost-phase interception. Many satellites are required because only a small share of the constellation is in the right place at the right time. CBO uses the term absenteeism for this problem: most satellites in orbit are absent from the immediate engagement zone when a launch occurs.

Altitude creates another cost pressure. Boost-phase interceptors must orbit low enough to reach missiles during the short powered phase of flight. CBO describes altitudes of roughly 300 to 500 kilometers. At those heights, atmospheric drag gradually lowers satellite orbits. The satellites need replacement roughly every five years. CBO estimates that roughly 30,000 satellites would need to be built and launched over 20 years to keep 7,800 active in orbit.

That replacement cycle is central to the cost. A ground-based interceptor can remain in a silo for many years and can be inspected, serviced, and upgraded. A low-orbit satellite interceptor has a shorter useful life and must be replaced by launch. The cost problem does not disappear even if launch becomes cheaper. CBO assumes $500 per kilogram to low Earth orbit, lower than typical recent launch prices and meant to reflect future heavy-lift systems such as SpaceX Starship. Even at that lower launch cost, launch accounts for less than 5 percent of the total space-based interceptor layer cost.

The space layer also carries strategic uncertainty. If the constellation can engage 10 missiles, it can help against a limited attack. It cannot fully absorb a large attack by a peer nuclear power. Making the layer large enough to handle a much larger attack would increase the satellite count and push costs much higher. CBO estimates that increasing the number of space-based interceptors by a factor of five would raise the 20-year cost of that constellation to about $3 trillion.

The space-based interceptor layer is best understood as the price of trying to add boost-phase defense to a homeland missile shield. Without that layer, the architecture would lose an explicit element of the executive order. With it, the program’s cost becomes dominated by satellites that must be built, launched, operated, and replaced at scale.

How the Ground Layers Change the Budget Picture

The ground layers in CBO’s notional national missile defense system are much less expensive than the space-based interceptor layer, but they still represent large defense investments. The upper wide-area surface layer includes the existing Ground-Based Midcourse Defense site at Fort Greely, Alaska, plus two new sites. CBO assumes each new site would include 60 Next-Generation Interceptors, a command facility, and a Long-Range Discrimination Radar. Each new site would cost about $15 billion to build and equip, with annual operating costs of about $410 million.

The upper surface layer focuses on intercontinental ballistic missiles in the midcourse phase. That phase occurs after boost, when the warhead travels outside the atmosphere. Midcourse defense is difficult because an incoming missile may release warheads, decoys, or other objects. The defense must discriminate between objects and assign interceptors under time pressure. CBO notes that a site with 60 interceptors could theoretically support 30 two-shot engagements, but real engagement planning depends on tactics, threat type, and interceptor design.

The lower wide-area surface layer uses Aegis Ashore-style sites. The United States already maintains Aegis Ashore facilities in Romania and Poland, although CBO’s notional U.S. sites would be configured for homeland defense. Each site would include a deckhouse and radar, a Mark 41 vertical launch system, Standard Missile 3 Block IIA interceptors, and supporting self-defense systems. CBO estimates each lower wide-area site at nearly $4 billion to deploy and about $170 million per year to operate.

Regional sectors are the most extensive ground component by count. CBO models 35 sectors, each designed to defend a region of roughly 270,000 square kilometers. These sectors include radars, command facilities, and interceptors such as the Glide-Phase Interceptor, Terminal High Altitude Area Defense, Patriot Missile Segment Enhancement interceptors, and Standard Missile variants. Their purpose is terminal defense against ballistic and hypersonic missiles, plus defense against cruise missiles and other airborne threats.

CBO stresses that real sectors would probably differ from one another. Coastal regions may need more cruise missile defense. Inland regions may place more emphasis on ballistic missile threats. Population density, terrain, military infrastructure, and radar visibility would shape the design. The 35-sector model is a cost framework, not a proposed site map.

The ground layers show that Golden Dome is not a single shield with one technical answer. It is a stack of defensive layers. Each layer buys another chance to engage an incoming threat, but each layer adds acquisition cost, operating units, training pipelines, sustainment needs, and integration work.

The next table summarizes the policy function of each layer without treating the public CBO architecture as an operational plan.

Missile Tracking, Command Systems, and Integration

A national missile defense system cannot work as a collection of disconnected interceptors. Sensors must detect launches, track objects, pass data to command systems, assign interceptors, update fire-control solutions, and maintain enough resilience to function during attack. CBO includes additional sensors, communications systems, and battle management systems because the layers must coordinate with each other and operate under demanding time limits.

The space tracking layer in CBO’s model includes 108 satellites in low Earth orbit and 27 satellites in medium Earth orbit. These satellites carry infrared sensors to detect and track missile threats, loosely based on the Tracking Layer of the Space Development Agency Proliferated Warfighter Space Architecture. CBO estimates that this tracking constellation would cost about $69 billion to develop, deploy, and maintain for 20 years, plus about $1 billion per year to operate.

The executive order specifically named the Hypersonic and Ballistic Tracking Space Sensor, a Missile Defense Agency prototype effort designed to track hypersonic weapons. CBO explains that the department’s space-based sensor programs remain partly undefined or classified. It is possible that HBTSS capabilities could be folded into broader Space Force missile warning and tracking programs. Program boundaries matter because they determine whether a cost belongs inside Golden Dome, inside general space modernization, or inside another defense account.

Command and control also affects cost and credibility. CBO’s notional architecture allows each layer to operate independently if higher-level national command links are disrupted. That design choice adds resilience, but it also requires local command facilities, operators, training, procedures, communications equipment, and maintenance. Redundancy costs money because it avoids reliance on a single command path.

CBO excludes some national and global communications systems from its estimate. For example, it does not include the full cost of broader space data networks or the Space Development Agency’s Transport Layer, because those systems may be developed for multiple military purposes. If Golden Dome places special speed, redundancy, or survivability demands on those networks, some additional costs could appear outside the Golden Dome fund.

Integration may become one of the program’s hardest management problems. Surface interceptors, space sensors, regional radars, command centers, and communication networks come from different acquisition lines and contractor bases. Many components have different development schedules and operating concepts. Even when individual systems exist, connecting them into a reliable homeland defense architecture creates testing, software, cybersecurity, training, and command-authority issues that can increase both schedule risk and cost.

Why the $185 Billion Figure Does Not Match the $1.2 Trillion Estimate

CBO compares its $1.2 trillion notional estimate with public statements from the director of the Office of Golden Dome for America, who cited a $185 billion cost for the program’s objective architecture over the next decade. CBO also notes that fiscal year 2027 budget request documents called for the Golden Dome for America Fund to receive an average of about $15 billion per year for the next five years. A later defense budget overview requested $17.121 billion for the Golden Dome fund in fiscal year 2027.

Those numbers do not necessarily contradict each other, because they may measure different things. CBO’s figure covers 20 years of development, deployment, replacement, and operation for a notional architecture with four interceptor layers and space tracking. The $185 billion public figure appears to cover a shorter period and may exclude operating costs, replacement costs, or systems funded through other accounts. It may also describe a smaller architecture than the one CBO built from the executive order.

Budget categories can obscure the real total. Interceptors could be purchased through service missile procurement accounts rather than the Golden Dome fund. Sensor programs could sit in Space Force lines. Missile Defense Agency research could cover work that later supports Golden Dome. Regional defense systems could draw from existing Army or Navy procurement channels. The absence of a released objective architecture makes it difficult to determine whether the public budget line reflects the full program or only a central fund.

Scope is the other reason for the gap. If the final Golden Dome architecture omits space-based interceptors, the cost falls sharply. CBO estimates that removing the space-based interceptor layer would reduce the 20-year total from $1.2 trillion to $448 billion. Such a design would not match the executive order’s explicit call for space-based interceptors, but it shows how strongly the total depends on one layer.

Coverage choices matter too. A system that protects only selected military sites, command centers, industrial facilities, and population regions could cost less than a system designed to provide broad national coverage. A design with fewer regional sectors would reduce costs, but it would leave more people and infrastructure with less protection. A system sized only for a small regional adversary attack would cost less than one sized to absorb larger salvos.

The following table shows why the headline figures differ.

Strategic Limits and Adversary Responses

CBO’s report is clear that the notional national missile defense system would be more capable than today’s U.S. homeland missile defenses, but it would not fully defeat a large-scale attack from Russia or China. That distinction matters because missile defense has two separate policy functions. It can defend against limited attacks, and it can influence how adversaries think about deterrence. The two functions do not produce the same budget or strategic effects.

Against a regional adversary with a limited number of long-range missiles, layered defense can raise the chance that an attack fails. That is the scenario where a system sized for 10 nearly simultaneous intercontinental ballistic missiles has the most direct meaning. It may reduce coercive value for a state with a small arsenal because the attacker cannot assume each missile will reach its target.

Against a peer nuclear power, the calculation changes. Russia and China can field larger missile forces, more complex attack plans, and penetration aids. CBO states that a full-scale peer attack could overwhelm the notional architecture. The system could still complicate a smaller attack, reduce the number of incoming threats that reach later layers, or defend against limited regional-use scenarios. It cannot replace nuclear deterrence, and it does not make the United States invulnerable.

Adversary response is a major uncertainty. A regional adversary could build more missiles or invest in decoys, maneuvering reentry vehicles, cyber operations, anti-satellite weapons, or cruise missile forces. A peer adversary could increase the size of missile salvos, diversify delivery systems, or treat the defense as evidence that it needs a larger offensive arsenal. Those responses could make the United States consider further missile defense expansion, which would add cost and deepen arms-race dynamics.

The space layer adds another strategic dimension. Satellites that can track or intercept missiles become part of the military space domain. That creates incentives for adversaries to develop ways to disrupt, disable, deceive, or destroy those satellites. It also links missile defense to space traffic management, orbital replacement rates, launch capacity, and satellite manufacturing scale. Golden Dome would be a defense and security program, but it would also affect the space industrial base.

CBO does not recommend for or against the system. Its analysis shows that policymakers face a choice between partial defense at very high cost and broader defense at even higher cost. The term “shield” can be misleading if it implies complete protection. The more accurate policy description is layered risk reduction against selected attack sizes and threat types.

Cost Growth, Industrial Capacity, and Deployment Timing

CBO does not assign a single deployment timeline to the notional national missile defense system. Some components could begin procurement sooner because they are based on existing systems. Other elements, especially space-based interceptors, would require years of development, testing, production, and launch activity. The full schedule would depend on funding, industrial capacity, siting decisions, testing outcomes, and the maturity of technologies that have never been fielded at this scale.

Industrial capacity creates an immediate constraint. The architecture uses many interceptors, radars, launchers, satellites, command systems, and trained personnel. Defense manufacturers would need to produce equipment at rates that fit the deployment plan. Launch providers would need to place and replace large numbers of satellites. The military would need to establish units, facilities, maintenance routines, and training systems. If Congress funds the program below planned annual levels, the schedule could stretch and total cost could rise.

Cost growth is a standard risk in large defense acquisition. CBO identifies several sources: specialized labor, rare materials, changing performance requirements, disrupted funding, schedule extension, and technological integration problems. Those risks are especially relevant to a layered system that combines ground-based missile defense, regional air and missile defense, space tracking, and space-based interception. The parts are expensive on their own, and the integration burden adds another layer of risk.

Operations and support costs also tend to grow faster than general inflation in defense programs. Personnel costs, health care, maintenance, contractor support, software updates, and replacement activity can increase over time. For Golden Dome, operations would include satellite control, radar operation, command staffing, site security, equipment maintenance, interceptor sustainment, and training. CBO’s O&S estimate already reaches $8.3 billion per year for the full notional system, with regional sectors alone accounting for more than half of that annual amount.

Deployment choices can reduce some costs and increase others. Fewer regional sectors lower acquisition and operating costs, but reduce coverage. A smaller space interceptor constellation lowers space costs, but reduces engagement capacity. More use of existing military land may reduce land-acquisition costs, but local siting, environmental review, utilities, and infrastructure still affect schedule. Relying on other defense accounts can make the Golden Dome fund look smaller, but it does not make the national resource cost disappear.

CBO also excludes several categories that could appear in broader policy debates. It does not include directed energy weapons, some left-of-launch capabilities, global communications systems, expanded ship patrols, fighter alert operations, broad small-drone defense, or land acquisition outside direct equipment-related construction. Those exclusions mean the $1.2 trillion estimate should not be treated as an upper ceiling for every possible Golden Dome-related policy package.

Space Economy Effects of a Homeland Missile Defense Buildout

Golden Dome would sit inside the defense and security vertical market, but its scale would reach across the space economy. A space-based interceptor layer with thousands of satellites would demand manufacturing capacity, launch services, orbital operations, ground control, tracking, replacement planning, and secure communications. Even a smaller final architecture would strengthen demand for missile warning satellites, resilient communications, and sensor fusion software.

The space-based elements would connect Golden Dome to the same industrial questions that affect commercial satellite constellations. Satellite production must be standardized enough for scale, but specialized enough for national security missions. Launch costs matter, but CBO’s estimate shows that manufacturing, integration, testing, replacement, and operations dominate the space-based interceptor layer. Cheaper launch helps, but it does not solve the full cost problem.

The program could also influence launch market demand. A constellation that needs roughly 30,000 satellites over 20 years would require sustained launch access. That would support heavy-lift and high-cadence launch providers, but it would also create scheduling, range, and space traffic coordination issues. A defense architecture with frequent replenishment launches cannot treat orbital replacement as a minor logistics task.

Ground systems would see parallel demand. The architecture includes radar sites, command centers, regional control facilities, secure networks, software systems, and training infrastructure. Companies involved in sensors, command and control, cybersecurity, systems integration, satellite buses, propulsion, optical links, and launch operations could all see procurement interest. The Defense Department would need to manage vendor dependence, supply-chain security, export controls, and workforce limits.

Insurance and risk management would also matter. A defense constellation could face collision risk, debris concerns, launch failure exposure, cyberattack, and anti-satellite threats. Military systems do not follow the same insurance model as commercial spacecraft, but program managers still need risk reserves, replacement plans, and operational redundancy. Large constellations also place greater pressure on space situational awareness, collision avoidance, and orbital debris mitigation.

The workforce demand could be substantial. Golden Dome would need aerospace engineers, missile defense specialists, orbital mechanics experts, software developers, radar engineers, cybersecurity personnel, launch operations staff, and military operators. Those skills overlap with commercial space, civil space, and defense programs. Competition for talent could affect wages, schedules, and program execution across the space sector.

Golden Dome’s space economy effect would depend on the final architecture. A design centered on ground layers and space tracking would still be a large procurement program, but a design retaining a full space-based interceptor layer would be a much larger industrial mobilization. In that case, the program would test whether the United States can sustain a national security satellite production and replacement cycle at a scale closer to commercial megaconstellations than traditional strategic defense programs.

Summary

CBO’s May 2026 estimate places a notional national missile defense system broadly consistent with the Iron Dome for America executive order at about $1.2 trillion over 20 years. That figure is not the confirmed cost of Golden Dome for America, because the Department of Defense has not released the final objective architecture. It is a structured estimate of what a homeland-scale layered defense could cost if it included the capabilities named in the executive order.

The largest cost driver is the space-based interceptor layer. CBO’s model uses 7,800 satellites in low Earth orbit and roughly 30,000 satellites over 20 years because the constellation must maintain coverage and replace satellites affected by orbital decay. Surface layers, regional sectors, space tracking, and integration add large costs, but they do not dominate the estimate in the same way.

The contrast between CBO’s $1.2 trillion estimate and public Golden Dome figures near $185 billion reflects scope, time period, budget category, and architecture differences. A smaller system could cost less. A larger system capable of handling bigger attacks could cost far more. Removing space-based interceptors sharply reduces cost, but it also removes an element specifically called for in the executive order.

Golden Dome’s policy question is not whether missile defense can provide some protection. It can. The harder question is how much protection the United States wants, against which threats, across which regions, at what cost, and with what strategic consequences. CBO’s report gives that debate a financial frame. It shows that architecture, not branding, determines the bill.

Appendix: Useful Books Available on Amazon

• The Dead Hand
• The Wizards of Armageddon
• Way Out There in the Blue
• Nuclear Strategy in the Modern Era
• The Bomb
• Nuclear Weapons and Coercive Diplomacy
• Arms and Influence

Appendix: Top Questions Answered in This Article

What Did CBO Estimate for a National Missile Defense System?

CBO estimated that a notional national missile defense system broadly consistent with the Iron Dome for America executive order would cost about $1.2 trillion over 20 years in 2026 dollars. That figure includes development, deployment, replacement, and operation for the architecture CBO modeled.

Is the $1.2 Trillion Figure the Official Cost of Golden Dome?

No. CBO states that the Department of Defense has not released enough detail about Golden Dome’s final objective architecture to estimate its exact long-term cost. The $1.2 trillion figure is CBO’s estimate for a notional architecture based on the executive order’s stated capabilities.

Why Is the Space-Based Interceptor Layer So Expensive?

The space-based interceptor layer requires thousands of satellites in low Earth orbit because only some satellites would be close enough to engage a missile during boost phase. CBO also assumes those satellites need replacement roughly every five years, which greatly increases lifetime acquisition cost.

Could Golden Dome Stop a Large Russian or Chinese Missile Attack?

CBO’s notional system would not fully counter a large-scale attack from a peer nuclear power. It could help against limited attacks and smaller raids, but a large salvo from Russia or China could overwhelm the architecture described in the estimate.

What Threats Does CBO’s Notional System Address?

The notional system addresses ballistic missiles, hypersonic glide vehicles, cruise missiles, and other aerial threats. Its layers are designed to give multiple engagement chances across different phases of missile flight, from boost phase to terminal defense near defended areas.

Why Do CBO’s Estimate and Public Golden Dome Cost Figures Differ?

They likely measure different scopes and time frames. CBO’s estimate covers a 20-year layered system with space-based interceptors and operations. Public figures near $185 billion appear to describe a shorter period, a narrower architecture, different budget categories, or a combination of those factors.

What Happens If Space-Based Interceptors Are Removed?

CBO estimates that removing the space-based interceptor layer would reduce the 20-year cost to about $448 billion. That lower-cost architecture would not align with the executive order’s explicit call for space-based interceptors, but it shows how much that layer drives total cost.

Why Does Missile Defense Need Space-Based Tracking?

Space-based tracking helps detect and follow missile threats before they come within range of ground radars. Earlier detection gives command systems more time to classify threats, assign interceptors, and coordinate layered responses across the architecture.

How Could Golden Dome Affect the Space Industry?

A space-heavy Golden Dome architecture would create demand for satellite production, launch services, secure communications, ground control, space tracking, and specialized software. The scale would depend on whether the final design includes a large space-based interceptor constellation.

What Is the Main Policy Tradeoff in Golden Dome?

The main tradeoff is between cost, coverage, and capacity. A smaller system costs less but protects fewer areas or handles fewer threats. A larger system provides more defensive capacity but can raise acquisition, operating, strategic, and industrial-base burdens.

Appendix: Glossary of Key Terms

National Missile Defense

A national missile defense system is a set of sensors, interceptors, command systems, and communications networks designed to protect a country from missile attack. In this article, the term refers to homeland-scale defense against long-range and advanced aerial threats.

Golden Dome for America

Golden Dome for America is the Department of Defense initiative associated with the January 2025 Iron Dome for America executive order. CBO treats it as an early-stage effort because the department has not publicly released a complete objective architecture.

Iron Dome for America Executive Order

The Iron Dome for America executive order directed the Department of Defense to develop plans for a next-generation homeland missile defense shield. It called for defenses against ballistic, hypersonic, cruise missile, and other advanced aerial threats.

Space-Based Interceptor

A space-based interceptor is a satellite-carried defensive system intended to engage a missile from orbit. In CBO’s model, this layer focuses on boost-phase interception, which requires many satellites because the engagement window lasts only minutes.

Boost Phase

Boost phase is the early part of ballistic missile flight when the rocket motor is still burning. It usually lasts only minutes for long-range missiles, making interception difficult because sensors, command systems, and interceptors must respond very quickly.

Midcourse Phase

Midcourse phase is the part of ballistic missile flight after boost, when the warhead travels outside the atmosphere. Midcourse defense can be complicated by decoys, separated objects, and the need to identify the real target.

Terminal Defense

Terminal defense refers to intercepting a threat near the end of its flight, closer to the defended region. CBO’s regional sectors provide terminal defenses against ballistic and hypersonic missiles, plus defense against cruise missiles and other air threats.

Hypersonic Glide Vehicle

A hypersonic glide vehicle is launched by a rocket, then glides through the upper atmosphere at more than five times the speed of sound. Its maneuverability can make tracking and interception more difficult than for a traditional ballistic path.

Aegis Ashore

Aegis Ashore is a land-based version of the Aegis ballistic missile defense system. CBO uses Aegis Ashore-style sites in its lower wide-area surface layer, mainly for late midcourse and shorter-range ballistic missile defense.

Operation And Support Costs

Operation and support costs are the recurring costs of running and maintaining a system after deployment. They include personnel, maintenance, repair, software updates, training, contractor support, and periodic equipment sustainment.