One concept for the Golden Dome missile defense system with space-based elements. (credit: Redwire)
By Carlos Alatorre,
Published by The Space Review, 8 September 2025
On January 27, 2025, President Trump signed an executive order authorizing the implementation of the Iron Dome for America, essentially a request for the Department of Defense (DOD) to develop a “reference architecture…for the next-generation missile defense shield.” Inspired by the eponymous Israeli missile defense system, the renamed “Golden Dome” project would provide a protective nationwide shield against ballistic, hypersonic, and cruise missile attacks of conventional or nuclear warheads.
| Space-based interceptors would have dramatic military and diplomatic implications, such that deploying interceptors in orbit may spark more escalation than deterrence. |
Golden Dome would utilize space-based sensors for tracking, command and control (C2) networks for communication, and ground-based interceptors (GBI) to eliminate incoming threats. A controversial addition to this project is the development of space-based interceptors (SBI), projectiles meant to stop a ballistic threat from hitting the US by colliding with the missile in the upper atmosphere. Due to increasing missile capabilities from China, Russia, Iran, and North Korea, a comprehensive and layered US ballistic missile defense system (BMDS) is necessary to respond to the evolving security environment. However, SBIs would have dramatic military and diplomatic implications, such that deploying interceptors in orbit may spark more escalation than deterrence.
Technical realities and operational architecture of golden dome
Before examining the implications of SBIs in orbit, we must first understand how ballistic and hypersonic missiles approach intended targets, as well as how our current BMDS aims to defend against them. According to the 2019 Missile Defense Review Supplement by the Missile Defense Agency (MDA), ballistic missiles follow a three-phase trajectory as they approach a target: the boost phase, the midcourse phase, and the terminal phase (this trajectory differs for hypersonic missiles).
- The boost phase lasts from the initial missile launch to when the first-stage booster is ejected. This phase is the ideal time to intercept the missile because it’s barely exited the atmosphere and is easiest to track due to the exhaust from the launch.
- The midcourse phase begins after the first-stage booster is ejected and the missile cruises along its trajectory in space. This phase presents several opportunities to destroy the missile as it arcs towards its intended target.
- Once the missile begins its descent to reenter the atmosphere, this signals the terminal phase, the last chance for any GBIs or sea-based interceptors to destroy the rocket.
- Hypersonic missiles have a boost phase but abandon the typical ballistic missile trajectory after the first-stage booster ejects, staying within the atmosphere. Two types of hypersonic weapons, glide vehicles and cruise missiles, have the potential to maneuver along their path to the target while evading radar detection.
As it stands, current US BMD capabilities revolve around destroying a ballistic missile threat in the midcourse and terminal phase. According to a US BMD defense primer from the Congressional Research Service:
- The Ground-Based Midcourse Defense (GMD) is the only hit-to-kill defense system the US has for homeland protection against intercontinental ballistic missiles (ICBMs). More than 44 GBIs, comprising multi-stage rockets and Raytheon-built Exo-atmospheric Kill Vehicles, are spread between Alaska and California, with an intended third site in Michigan, Ohio, or New York by 2030.
- The Terminal High-Altitude Area Defense (THAAD) is a mobile radar and defense system aimed at destroying missiles in the terminal phase using hit-to-kill GBIs. Eight systems are fielded in multiple locations, like Guam, Saudi Arabia, and South Korea. Despite its success seen most recently during the Israel-Iran Conflict, over 150 GBIs were expended to defend Israel against Iran’s barrage, nearly a quarter of Israel’s total purchases. This highlights how quickly interceptors can be expended in a short time.
- The Navy’s Aegis BMD and the Army’s Patriot Advanced Capability (PAC-3) overlap with THAAD to provide a layered defense against short- and medium-range ballistic missiles. Aegis can target rockets in the midcourse phase, while both can target rockets in the terminal phase using SM-3/SM-6 and Patriot interceptors, respectively.
Each fielded system is designed to deter an attack on the homeland and regional military bases. While THAAD, Aegis, and PAC-3 have had success in defending against regional attacks by short- and medium-range ballistic missiles, none of these systems is equipped to defend against a sophisticated Chinese or Russian ICBM. The GMD is the only part of the US BMDS that can adequately protect against limited attacks from North Korea or Iran, but falters against large-scale attacks from nuclear powers like China or Russia, according to an updated report by the American Physical Society. Out of the 19 test ICBMs launched, 10 were destroyed by US BMD interceptors since 1999. The GMD itself was used twice during that time and succeeded in killing two ICBMs after using three GBIs per missile.
Based on this information, targeting a ballistic or hypersonic missile during the boost phase is the safest and most ideal period for US homeland defense; however, it’s the most challenging phase to target. You would need to be in very close proximity to the launch site or positioned directly overhead to destroy the missile as it ascended, something our current BMDS cannot do.
| The Golden Dome project can be seen as an ambitious and grand patchwork tapestry, stitched together to defend the nation. |
Enter Golden Dome. Rather than a literal shield, Golden Dome represents an integrated system of systems employing multiple programs that utilize space architecture to provide tracking, data collection, and communications capabilities, along with ground-based radar, control centers, and mobile assets that fire interceptors. As Gen. Chance Saltzman stated at the Space Symposium in April, “There won’t be a single contract vehicle…there will be multiple programs…to solve that mission against the threats. You orchestrate a program that includes a lot of programs that you have to stitch together in very technical ways.”
Therefore, any program implemented will be a small piece of an ever-expanding puzzle, the likes of which have not yet been completely fleshed out. Golden Dome Project Manager Gen. Mike Guetlein stated in late July that he will provide a plan for the foundational architecture of the system within the next 60 days, with a heavy focus on C2. The systems in question won’t be built from scratch. They’ll be expanded from the existing BMDS (GMD/THAAD/Aegis) and linked with three satellite networks that were implemented in 2019:
- Proliferated Warfighter Space Architecture (PWSA) — Space Development Agency (SDA)
- Hypersonic and Ballistic Tracking Space Sensor (HBTSS) — MDA
- Resilient Missile Warning Missile Tracking MEO — Space Force’s Space Systems Command (SSC)
In 2022, the Space Force established a Combined Program Office to coordinate the missile warning and tracking efforts of the PWSA, HBTSS, and MEO satellites, which will form the backbone of the future space-based sensor system. While overlapping in capability, PWSA offers the most extensive missile warning and tracking by utilizing seven layers of 550 networked satellites. The HBTSS will be a more sensitive and focused network, specifically designed to detect hypersonic missiles as part of the planned tracking layer of the PWSA. The Golden Dome project can be seen as an ambitious and grand patchwork tapestry, stitched together to defend the nation. Yet it requires a controversial component to its function: the inclusion of space-based interceptors as essential to neutralizing ballistic missiles during their boost phase.
Diplomatic implications of SBIs in orbit
Most critics discuss the technical impracticality of maintaining interceptors in LEO or the exorbitant cost of fielding the required number of SBIs in orbit A single interceptor could be stationed in GEO with a constant view of the offending country (such as China or Russia). But, given the distance, an interceptor wouldn’t reach the targeted ballistic missile before it left boost phase, defeating the purpose of an SBI. This means interceptors would have to be placed in LEO, and many would be needed to have constant coverage of the country as they orbited Earth.
As for the cost, the estimated number of 1,900 SBIs (the projected number required to be kept in LEO to have continuous coverage) is around $27 billion, according to AEI’s Senior Fellow Todd Harrison, which would only account for two ballistic missile launches at a time.
However, the real issue lies in how this may affect space governance and behavioral norms in a time when the global space economy has surpassed $630 billion and space is now being seen by most nations as a necessary warfighting domain.
Diplomatically, the orbital placement of kinetic, hit-to-kill SBIs poses a host of problems for the US long-term. This year, on the 80th anniversary of V-E Day, Russia and China issued a joint statement warning against global strategic instability and condemning the US for Golden Dome’s plan to place SBIs in orbit. This statement must be taken with healthy skepticism, given that China and Russia constantly promote themselves as models of good governance while rejecting US-led norms, unless those align with their interests. Both countries have increased gray-zone operations in orbit, the most prominent being Russia’s alleged plans to deploy a nuclear device in space. Despite this, China and Russia have consistently framed US space operations as aggressive while promoting themselves as the leaders in space governance.
In 2008, China and Russia jointly submitted a draft on the Prevention of the Placement of Weapons in Outer Space and of the Threat of Use of Force Against Outer Space Objects (PPWT), a self-explanatory set of rules prohibiting weapons placement in orbit. This draft was updated in 2014 and includes rhetoric such as “Nothing [can prevent China or Russia] from exploring and using outer space for peaceful purposes.” The US and its partners disagreed with the language of this draft because, according to Ambassador Robert Wood, it lacked an acceptable verification mechanism and didn’t mention any ban on ground-based antisatellite weapons (ASAT). Even with an agreement in place, space assets could still be vulnerable to interceptors fired from the ground (direct-ascent ASATs), an exercise only four countries have performed, including China and Russia.
| While the Golden Dome project presents a bold reframing and integration of existing capabilities in US missile defense to meet 21st-century threats, the inclusion of SBIs introduces a host of strategic, diplomatic, and military dilemmas that could lead to global destabilization. |
As the leader in space exploration and the country that legitimizes international standards, the US should be the country that champions the development of space norms of behavior, not China or Russia. In 2022, the US took a significant step forward by implementing a unilateral ban on performing direct ascent ASAT tests, hopefully the start of a continuing process to push for an international moratorium on direct-ascent ASATs. If SBIs are placed in orbit for any reason, the US would lose any influence it has in modeling a rule-based order in space. Any country with significant funding in its space program, especially those not allied with the US, would most likely attempt to place SBIs in orbit as a “defensive” measure. This is apparent in the way countries like the Philippines and Vietnam have begun militarizing their small pieces of the South China Sea, a defensive response toward China’s perceived aggressive actions.
Military implications of SBIs in orbit
This leads to the military implications of orbital SBIs. Placement of US defensive space architecture could create a pretext for China and Russia to expand their space presence via militarization. In a previous article I wrote on China’s spaceplane being a potential co-orbital ASAT (see “Hiding in plain sight: Is China’s spaceplane a co-orbital ASAT in disguise?”, The Space Review, September 25, 2023), I discussed the PLA’s plans, intentions, and capabilities of denying the US space access through the use of gray-zone activities; tactics based mainly on previous US operations in space. Case in point, the PLA-operated Shenlong spaceplane was an exact copy of the US spaceplane, the X-37B, and launched on a mission of its own after the Space Force concluded the US spaceplane mission. Whether the US likes it or not, China takes its cues on what can be done in space based on our example. Orbital SBIs would be no exception.
Another consideration is that, according to NASA’s current timeline, by 2030, the International Space Station (ISS) will be decommissioned with a splashdown in the Pacific, potentially leaving the US and its allies with no human presence in orbit. But China and Russia will have one; the Tiangong space station will become the soft power symbol of human-led space exploration, absent a Moon landing.
Why is this a military issue and not a diplomatic one? Because Article IV of the China/Russia-led PPWT draft states, “This Treaty shall by no means affect [China’s and Russia’s] inherent right to individual and collective self-defense, as recognized by Article 51 of the UN Charter.” The Outer Space Treaty of 1967 may prevent countries from claiming celestial bodies and creating borders in space, but it doesn’t ban countries from defending themselves if threatened. China has always been a proponent of dual-use technology, demonstrated in its Military-Civil Fusion strategy. Any technology that can be operated and fielded for commercial purposes can and will be converted militarily if it gives an advantage to the user, according to Chinese strategic thinking. This mentality is projected onto every aspect of US civil and commercial practice. This will no doubt drive China’s (and the PLA’s) thinking that any US-fielded orbital SBI will inevitably be used as an offensive weapon, which puts Chinese lives on the Tiangong at potential risk. At least that will be the rhetoric.
Conclusion
While the Golden Dome project presents a bold reframing and integration of existing capabilities in US missile defense to meet 21st-century threats, the inclusion of SBIs introduces a host of strategic, diplomatic, and military dilemmas that could lead to global destabilization. SBIs offer the promise of intercepting threats at the boost phase, the most vulnerable stage to target ballistic missiles. But their deployment could erode international norms, undermining US influence in establishing responsible space behavior and provoking adversarial responses that could escalate tensions in orbit. Emboldening adversaries to militarize space further is the opposite of what’s needed for an effective BMDS.
Rather than publicly pursue and appropriate funds for inflammatory solutions, the US should invest in less overt BMD options. Directed-energy weapons, improved GBIs like the Glide Phase Interceptor, and, most importantly, cyber capabilities should be the primary focus of investment. Whatever the administration decides for this project, nothing so escalatory as SBIs should be announced publicly while US adversaries maneuver through the gray-zone space. Until the US decides to take a page from the gray-zone playbook of China and Russia, the central question remains: Is security through dominance sustainable, or does it make that same security more elusive across multiple warfighting domains? The Golden Dome’s SBIs may act as a shield, but if we’re not careful, they could become the spark for the very conflict we seek to avoid.
See: Original Article
