Abstract
The US announcement that its Space Force has on-orbit space control weapons has left their nature, purpose, and legal status murky. In this article, it is argued that the main risk to stability is the ambiguity surrounding such systems, rather than their existence per se. It examines gaps in the Outer Space Treaty, why the nature of the weapon and its targets matter for crisis stability, and how signalling can reassure. It proposes voluntary transparency and confidence-building measures that states could consider alongside legally binding commitments in the UN Open-ended Working Group on the Prevention of an Arms Race in Outer Space in all its Aspects (OEWG on PAROS).
Introduction
On 14 September, US Air Force Secretary Troy Meink announced that the Space Force has “on-orbit space control weapons capable of defending the joint force against hostile adversary action”. He confirmed the capability but not the nature of the weapons. What we do know is that the US Space Force defines space control as “[consisting] of offensive and defensive actions, referred to as counterspace operations”. This creates not only ambiguity but suspicion in the perception of adversarial states and consequently prompts corresponding countermeasures. The main risk to stability is not the deployed weapon system but the secrecy and ambiguity around it. The most practical approach to reduce such a risk lies in a combination of legally binding commitments and transparency and confidence-building measures (TCBMs) for states to consider in the OEWG on PAROS.
What is Known, What is Not, and New Questions Facing Old Law
Meink did not say what kind of weapons are in orbit, but it was the first time a US official has publicly acknowledged their existence. Language matters: “space control” may include offensive and defensive actions, such as electromagnetic warfare, and Meink himself said those capabilities can be used for either purpose. Analysts have said the counterspace systems are more likely to be non-kinetic, such as jammers and spoofing, rather than kinetic.
The current legal framework on space affairs was built for a different era. Article IV of the Outer Space Treaty prohibits the placement of nuclear weapons and other weapons of mass destruction (WMD) in orbit, but does not prohibit other weapons from being placed in orbit. The treaty is the cornerstone of space law, but does not completely address new counterspace systems of today. Some analysts interpret it more broadly because the treaty stresses “peaceful purposes”, and it is notable that Article 2(4) of the UN Charter, which prohibits the threat or use of force, also applies to space. In this context, the issue of addressing new counterspace systems and the void in addressing weapons placement in orbit is not a breach of international law; it is just a gap. Recent events show a clear desire for restraint alongside practical limitations. In 2022, 155 states supported a resolution at the UN General Assembly that called for a moratorium on destructive direct-ascent anti-satellite tests; few have made national pledges, but the votes are nonbinding undertakings.
Not All Space Weapons are Equal
“Space weapon” warnings are usually generic. Crisis stability depends on what a weapon does to what target and how it is read. Let’s look at three hypothetical cases. A reversible space-based jammer against one military imaging satellite. If the satellite target supports target identification and damage assessment, the interference would be significant but limited and could be turned off. Physics also limits such a system: satellites have only limited propellant, and a large fleet is unlikely, so only a few adversary satellites could be affected at a time by this hypothetical space-based jammer.
Disruption of satellites that provide early warning or nuclear command and control would be much more dangerous. A target state may not be able to discern a malfunction from the first move in an attack. That ambiguity is the province of compressed decision timelines and pre-emptive use-it-or-lose-it pressures.
Debris-producing kinetic weapons are also a different kind of risk, less likely than interference with nuclear command and control, but harmful to the space environment. This is because kinetic weapons leave debris that can even endanger the satellites of the state firing them, and US officials have repeatedly warned against the use of such weapons.
Another question is about the Golden Dome, the recently initiated US missile-defence programme. Reportedly, the interceptors it plans to put in space are designed to destroy missiles in flight, but they can also be potentially used to target other objects in space. A large constellation of armed satellites could normalise the permanent basing of kinetic weapons in space, and critics warn this could incentivise others to expand their strategic forces. Advocates argue that missile defence can help strengthen deterrence by limiting damage if deterrence fails (also known as damage limitation), while critics say it can look like preparation for a first strike. This is an ongoing debate, and that’s why transparency measures matter. Transparency is about what systems can potentially do and against which targets they can be used. This transparency allows states and experts to know the real capabilities rather than assuming the worst possibilities without complete knowledge. Disclosure also reassures: if a state explains what such systems can and cannot target, others can judge whether they endanger their forces.
Signalling and the Security Dilemma
Disclosure is supposed to discourage, but it also changes the behaviour of others. In the security dilemma, one state’s security measures can make others feel less secure, so disclosures can reassure or alarm depending on what they clarify. This matters here because transparency only provides stability if it clarifies both intent and capability. The Chinese Foreign Ministry warned against making space a “battlefield”, while Russia said space should be free of any kind of weapons, although the Secure World Foundation counterspace report documents that Russia, as well as the US and China, is developing counterspace capabilities. Victoria Samson of the Secure World Foundation warned: “The announcement [of an on-orbit US space weapon] could lead to others confessing to their own systems, fuelling a cycle where someone eventually exploits one”. Deterrence only works if the signal is clear and the details are not withheld. Transparency for deterrence without confidence building and reassurances can even be “weaponised”.
A Balanced Way Forward
The OEWG will convene twice a year in Geneva until 2028. Its 2026 agenda includes intentional destruction, weapons placement, and proximity operations, as well as both legal obligations and voluntary measures. States are split over the instrument, with some preferring a binding treaty and others voluntary norms due to verification challenges. So the practical road is TCBMs now, with binding commitments where there is consensus.
Existing TCBMs are useful. Article XI of the Outer Space Treaty addresses information-sharing, and the Registration Convention was intended to promote transparency. In 2013, the UN expert group agreed on voluntary measures regarding information exchange, notifications, risk reduction, and consultation, with pre-launch notification being an established practice under the Hague Code of Conduct. Their first weakness is specificity: the treaty doesn’t explain how to notify about proximity operations. Another weakness is limited use: UN COPUOS papers note continued non-registration and incomplete registration data. Enforcement by the UN is not as practical as encouragement. Building on the current voluntary “additional information” section of the UN registration form, the OEWG could establish a common template for the voluntary disclosure of further information, including as it pertains to manoeuvres, and ask states to share their respective notification practices during its sessions.
Four approaches could be helpful.
- Use Article XI of the Outer Space Treaty for manoeuvre notifications. The Secure World Foundation has suggested using it as a conduit for greater information exchange, as the UN could distribute notifications widely and on time.
- Make notification rules measurable. Delta-V rather than just distance alone is crucial to characterising proximity operations, so the thresholds should also account for delta-V. Operators can announce their planned manoeuvres ahead of time without depending on the tracking capabilities of other states. States would decide on a common reporting format and principle, then use their own systems to put it into practice.
- Create a channel for voluntary interference clarification. This is not covered by the current channels: Article IX consultations under the Outer Space Treaty relate to potential activities, not interference that has already commenced. The ITU consultation process for harmful radio-frequency interference only deals with radio interference, has no enforcement power, and leaves states free to decide on military radio installations. When a state encounters unexplained interference, it may ask the suspected state if it was deliberate within a mutually agreed-upon time frame. This aids in separating hostile behaviour from malfunctions or natural causes.
- Offer voluntary capability-class declarations. States would not reveal operational details or attacks. Instead, they would describe in broad strokes the type of impact their on-orbit systems are meant to generate (e.g., reversible or not, debris-producing or not), as well as whether or not they are meant to be used against strategic-support satellites. Because they limit worst-case assumptions and provide others with a benchmark for evaluating future behaviour, such statements foster confidence rather than just serve as a deterrent.
Where the support is strongest, binding commitments can be made, such as turning the destructive-testing moratorium into a legal obligation. Shared understandings can be a precursor to legally binding instruments over time, as the United States has informed the OEWG. On this point, Italy, among others, has characterised norms as a precursor to a legal instrument, so the two tracks can be mutually reinforcing. During the last session of the 2022–23 OEWG on Reducing Space Threats Through Norms, Rules and Principles of Responsible Behaviours, a cross-regional joint statement delivered by the Philippines on behalf of 33 states called for the final report to affirm that political commitments on responsible behaviour can support the pursuit of legally binding measures.
Conclusion
Secrecy about the nature and purpose of a space control weapon invites worst-case thinking. Not all hypothetical systems pose a destabilising threat to stability, but ambiguity makes it difficult to determine which systems do. If practical CBMs are combined with verifiable legal limits, then all states will have more predictability, regardless of which instrument they prefer. The aim is not to settle the argument about control of space, but to prevent ambiguity from sparking or exacerbating a crisis: to that end, this article calls for voluntary transparency measures now, and binding limits where consensus can be reached.
All views expressed, as well as any errors, remain the sole responsibility of the author.