Can Space Be Disrupted Like the Strait of Hormuz?

During the conflict in the Middle East, Iran has exploited its location next to a transit corridor vital to international commerce and energy markets, effectively closing the Strait of Hormuz to international maritime traffic. To achieve this feat, Iran neither established sea control nor air superiority over the strait; instead, it applied a relatively small amount of force—and the threat of using more—to achieve its goals. A nation applying this playbook to outer space could produce equally consequential results. Similar to transit rights through the strait, all nations have the right to freely use space—a right that is perhaps taken for granted. Unlike the Strait of Hormuz, all countries border space and, with the right technology, can threaten it. Nearly 80 percent of all operational satellites orbit less than 800 km from the Earth’s surface, a distance within reach of many ballistic missiles. The fact that space is under threat has been known for years. The lesson on display in the Strait of Hormuz is that disruption can be achieved and sustained without having domain superiority, and that, once disrupted, it is hard to return things to the old normal.

Although the Strait of Hormuz is located in the territorial waters of both Oman and Iran, it is recognized under customary international law and the UN Convention on the Law of the Sea as an international strait, which means ships from any nation are guaranteed the right of transit passage. All nations enjoy similar rights to send spacecraft through outer space. The Outer Space Treaty of 1967 (OST) states that space is free for “exploration and use by all States.” This right, first de facto exercised a decade earlier, in 1957, with the launch of Sputnik by the Soviet Union, has been an essential lubricant for the growth of humankind’s activities in orbit since the dawn of the space age. Given the nature of orbital dynamics, a regime modeled like the one used for international aviation would have been unwieldy, requiring spacecraft operators to obtain permission from countries when satellites overflew their terrestrial boundaries. In 1976, eight equatorial countries asserted sovereignty over positions in geostationary orbit located above their national territories—but no spacefaring nation at that time supported the declaration.

Today, more nations use space—around 100 nations currently operate or in the past have operated spacecraft—than at any time in history, with most satellites owned and operated by companies and not government agencies. In the 1970s, the most important satellites were located in higher orbits, like geosynchronous orbit, which is over 35,000 km from Earth. But things look different today. Space is still critically important for national security, but also incredibly valuable from an economic standpoint, with the space economy positioned to grow to $1 trillion by 2034. Of all nations, the United States reaps the most economic benefit from space through its dominance of the space economy. The United States also depends on space for its defense. With initiatives like the Golden Dome, the United States looks to further expand its use of space for national security.

Any nation that can build and launch ballistic missiles has the basic building blocks for an anti-satellite weapon. As of 2023, about 30 countries possessed ballistic missiles. A credible weapon would only need to reach low Earth orbit (LEO)—this is the choke point in space analogous to the Strait of Hormuz. As already noted, nearly 80 percent of all satellites are below 800 km in altitude, with about 91 percent of all U.S.-registered satellites below that altitude. As the crow flies, the distance between the Iranian border and Israel is around 950 km—a range Iran has had no trouble reaching with missiles. Such distances are within range of a medium- or long-range ballistic missile, whose trajectories take them hundreds, if not thousands, of kilometers into space. Beyond missiles, cyberattacks, signal jamming, energy weapons, and laser dazzlers could also be used to cause disruptions or exert control of space.

A nation would not need space superiority to cause meaningful disruptions to LEO. Destroying or disabling even a small number of satellites—or merely just detonating devices in LEO that generate high-energy debris fragments—would cause considerable problems. It would inject a considerable amount of new risk into the business case for space, with implications for the space economy. This is like the risk Iran’s actions have imposed on maritime commerce, with impacts to insurance, through the Strait of Hormuz. It would also make space operations much more complicated—more debris makes safely flying satellites harder. For the most part, countries that have demonstrated the ability to strike satellites in space—China, India, Russia, and the United States—have all had to balance the advantages of using such weapons with the downside of debris creation. To date, that means that no nation has used a destructive anti-satellite weapon against a space system operated by another country.

But the calculus for using a destructive weapon in space may be changing. Russia has been accused of developing a space-based nuclear anti-satellite weapon. The commander of U.S. Space Command said Russia would use such a weapon to gain an advantage over the United States and NATO, such as by “neutralising our space capabilities, [helping] them to level the battlefield.” Russia is also reportedly looking at a weapon that would eject thousands of “high-density pellets” into LEO. Could Russia use these weapons as a means to disrupt the economic viability of space? This would look similar to how Iran—which itself is a beneficiary of economic gains derived from the strait—has used force to disrupt the Strait of Hormuz. Perhaps, like Iran, there may come a time when Russia sees more to gain from disrupting LEO, which Russia uses for its own benefit, for everyone. No doubt disrupting space would disproportionately negatively impact the United States.

Rather than to disrupt, a nation might seek to control space, perhaps arguing for the right to tax some or all satellites passing over its national territory. A nation might also assert the right to ban certain types of satellites from flying overhead, an action not compatible with the OST’s free use provision. Before the launch of any space-based interceptor satellites as part of the Golden Dome initiative, China or Russia could proclaim a ban on satellites armed with missiles from flying over their national territories. Either nation could back up such an assertion with a threat to shoot down any missile-carrying satellite that overflies its territory. The United States could call their bluff and launch the space-based interceptors—but it should be clear that such a chain of events could quickly lead to unintended escalation. It is worth thinking now: How would the United States respond to such a scenario, should a nation try to restrict space overflight rights by threat or force?

For one, the United States should diplomatically engage, in coordination with its allies, with China and Russia to address the underlying U.S. strategic concerns driving the need for space-based interceptors, as part of the Golden Dome, and the broader question of modernizing space governance. Such engagement would be more efficacious if it happened before China or Russia develops a new military or political response to the deployment of space-based interceptors. Dissuading a roguish actor, like Iran, from disrupting space may prove challenging. This also goes to the challenge of dissuading Russia from developing a space-based nuclear weapon, which was in the works before the announcement of the Golden Dome. The United States and its allies could include scenarios in which a nation tries to deny overflight rights for some or all satellites as part of wargames and tabletop exercises.

Rather than assuming it is possible to convince Iran, Russia, or any other country that it is not worth disrupting space, a parallel-path solution may be to develop ways to mitigate the impacts of anti-satellite weapons. This might include technologies that protect remote sensing satellites from laser dazzlers and quickly mitigate and remove debris from LEO. Focusing on technologies that could help satellites conduct more maneuvers over their lifetimes, as a way to raise their altitudes to escape debris fields and then return to the proper orbits, is another possible way to mitigate the threat of debris. A solution is possibly satellite refueling technologies, particularly for high-value spacecraft. The Pentagon may also want to rethink the wisdom of putting so many eggs in the LEO basket, terminating programs in higher orbits that might be harder, though not impossible, for our adversaries to reach than satellites in lower orbits, and leaning heavily on LEO for future military global communications capabilities.

But ultimately, should any of the aforementioned series of events play out, it might prove difficult to quickly resolve disruptions to the free passage of spacecraft in orbit. The United States would have few immediate options other than the application of its own superior military force, in space or other domains, to remove such a threat. This is a reality the world now faces in the Strait of Hormuz. The United States has time now to consider how best to avoid this reality from materializing—time that it should spend coordinating with allies and, when appropriate, engaging with counterparts in China and Russia. That time should also be spent assessing the value of maintaining more key space capabilities in diverse, farther-away orbits and developing and operationalizing technologies to mitigate the causes of disruptions, such as debris creation.

Clayton Swope is the deputy director of the Aerospace Security Project and a senior fellow in the Defense and Security Department at the Center for Strategic and International Studies in Washington, D.C.