Space Threat Assessment 2018

Space Threat Assessment 2018 analyzes the open-source information available on the counterspace capabilities of other countries that can threaten U.S. space systems.

The following article is an excerpt from Space Threat Assessment 2018, a report from the CSIS Aerospace Security Project. Download a PDF version of the full report here.


THE UNITED STATES REMAINS A LEADER in the use of space for military purposes. From hunting down terrorists in remote parts of the world to securing a credible nuclear deterrent, the United States uses space systems across the full spectrum of military operations. Current U.S. military strategy relies on being able to project power around the world and over great distances—something space-based capabilities are uniquely able to support. But as the United States has developed more advanced national security space systems and integrated them into military operations in increasingly sophisticated ways, potential adversaries have taken notice. The U.S. military’s dependence on space makes these systems a natural target for adversaries to exploit. Space is simultaneously a powerful enabler for the U.S. military and a critical vulnerability.

U.S. national security space systems are vulnerable to a wide array of threats, ranging from cyberattacks and jamming to direct-ascent anti-satellite (ASAT) missiles. While some U.S. space systems incorporate protections against certain types of attacks, all are vulnerable in certain ways.For example, the latest generation of protected satellite communications satellites, known as Advanced Extremely High Frequency (AEHF), incorporate a high degree of protection against jamming, spoofing, and other forms of electronic attack. But these satellites remain susceptible to kinetic attack, such as direct-ascent ASAT missiles or co-orbital weapons.

“The [Defense] Department will prioritize investments in resilience, reconstitution, and operations to assure our space capabilities.”2018 National Defense StrategyU.S. Department of Defense 1

While the vulnerabilities of U.S. national security space systems are often discussed publicly, the progress other nations are making in counterspace systems is not as readily accessible. The purpose of this report is to review the open-source information available on the counterspace capabilities of others that can threaten U.S. space systems. The report focuses on four specific countries that pose the greatest risk for the United States: China, Russia, Iran, and North Korea. Following these case studies, a fifth section analyzes the counterspace capabilities of other actors, including allies and partners of the United States, other nations, and some non-state actors.

This report is not a comprehensive assessment of all known threats to U.S. space systems because much of the information on what other countries are doing to advance their counterspace systems is not publicly available. Instead, this report serves as an unclassified assessment that aggregates and highlights open-source information on counterspace capabilities for policymakers and the public.

This report classifies counterspace weapons into four categories: Kinetic Physical, Non-Kinetic Physical, Electronic, and Cyber. Each category differs in its development, deployment, detection, and attribution.

Image Source: Caroline Amenabar / CSIS

COUNTERSPACE WEAPONS CAN VARY significantly in the types of effects they create, the level of technological sophistication required to conceive them, and the level of resources needed to develop and deploy them. Counterspace weapons also differ in how they are employed and how difficult they are to detect and attribute. The effects of these weapons can also be temporary or permanent depending on the type of system and how it is used. This assessment uses four broad categories to discuss different types of counterspace weapons.

Kinetic Physical Counterspace Weapons

KINETIC PHYSICAL COUNTERSPACE WEAPONS ATTEMPT to strike directly or detonate a warhead near a satellite or ground station. A direct-ascent ASAT weapon attempts to strike a satellite using a trajectory that intersects the target satellite without placing the interceptor into orbit. Ballistic missiles and missile defense interceptors can be modified to act as direct-ascent ASAT weapons, provided they have sufficient energy to reach the target satellite’s orbit. A co-orbital ASAT weapon differs from a direct-ascent weapon because it is first placed into orbit and then, when commanded to do so, the satellite maneuvers to strike its target. Co-orbital ASATs can lie dormant in orbit for days or even years before being activated.2 A key technology needed to make both direct-ascent and co-orbital ASAT weapons effective is the ability for the interceptor to sense and autonomously guide itself into a target satellite. This guidance technology requires a high level of technological sophistication and significant resources to test and deploy. Both are also enabled by associated targeting and command and control capabilities. An un-guided co-orbital ASAT, such as a satellite that is repurposed to intentionally maneuver into the path of another satellite, can be a nuisance and interfere with the normal operation of the targeted satellite by forcing it to maneuver to safety. However, an incident like this is unlikely to pose a serious collision risk without on-board guidance and sophisticated targeting capabilities.

“New threats to commercial and military uses of space are emerging, while increasing digital connectivity of all aspects of life, business, government, and military creates significant vulnerabilities. During conflict, attacks against our critical defense, government, and economic infrastructure must be anticipated.”2018 National Defense StrategyU.S. Department of Defense 3

Ground stations can also be vulnerable to kinetic physical attacks by a variety of conventional military weapons, ranging from guided missiles and rockets at longer ranges to small arms fire at shorter ranges. Ground stations can be easier to attack in some respects because they are often highly visible, located in foreign countries, and are relatively soft targets. Ground stations can also be disrupted by attacking the electrical power grid, water supply, and the high-capacity communications lines that support them.

Kinetic physical attacks tend to have catastrophic and permanent effects on the satellites and ground stations they target. These counterspace weapons are likely to be attributable because the United States and others can identify the source of a direct-ascent ASAT launch or ground attack, and can, in theory, trace a co-orbital ASAT’s orbital data back to its initial deployment. Moreover, an attacker is likely to know if its attack is successful almost immediately because of effects that would be publicly visible, such as orbital debris.

Non-Kinetic Physical Counterspace Weapons

NON-KINETIC COUNTERSPACE WEAPONS, such as lasers, high-powered microwaves, and electromagnetic pulse weapons, can have physical effects on satellites and ground stations without making physical contact. These attacks operate at the speed of light and in some cases, can be less visible to third party observers and more difficult to attribute. High-powered lasers can be used to damage or degrade critical satellite components, such as solar arrays. Lasers can also be used to temporarily dazzle or permanently blind mission-critical sensors on satellites. Targeting a satellite from Earth with a laser requires high beam quality, adaptive optics, and advanced pointing control to steer the laser beam as it is transmitted through the atmosphere—technology that is costly and requires a high degree of sophistication.4 A laser is effective against a sensor on a satellite if it is within the field of view of that sensor, making it possible to attribute the attack to its approximate geographical origin. The attacker, however, will have limited ability to know if the attack was successful because it may not produce debris or other visible indicators.

A high-powered microwave (HPM) weapon can be used to disrupt a satellite’s electronics; corrupt data stored in memory; cause processors to restart; and, at higher power levels, cause permanent damage to electrical circuits and processors. A “front-door” HPM attack uses a satellite’s own antennas as an entry path, while a “back-door” attack attempts to enter through small seams or gaps around electrical connections and shielding.5 Because electromagnetic waves disperse and weaken over distance and the atmosphere can interfere with transmission at high power levels, an HPM attack against a satellite is best carried out from another satellite in a similar orbit or a high-flying platform. Both front-door and back-door HPM attacks can be difficult to attribute to an attacker, and as with a laser weapon, the attacker may not know if the attack has been successful.

The use of a nuclear weapon in space is an indiscriminate form of non-kinetic physical attack. While a nuclear detonation would have immediate effects for satellites within range of the electromagnetic  pulse it creates, the primary effect of a nuclear detonation in space is that it creates a high radiation environment  that accelerates the degradation of satellite components over the long-term for all unshielded satellites in the affected orbital regime.6

Electronic Counterspace Weapons

ELECTRONIC ATTACKS TARGET the means by which space systems transmit and receive data by jamming or spoofing radio frequency (RF) signals. Jamming is a form of electronic attack that interferes with RF communications by generating noise in the same frequency band and within the field of view of the antenna on the satellite or receiver it is targeting. Jamming is usually completely reversible because once a jammer is turned off, communications can return to normal. Commercial and military satellites can be susceptible to both uplink and downlink jamming.7 The uplink refers to the communications signal going up to the satellite, while the downlink is the signal that is sent from the satellite back to the ground.8 An uplink jammer can interfere with the signal going up to a satellite, such as the command and control uplink, if it is within the field of view of the antenna on the satellite receiving the uplink.9 Downlink jammers do not have to be as powerful as uplink jammers and target the users of a satellite by creating noise in the same frequency and at roughly the same power as the downlink signal from the satellite within the field of view of the receiving terminal’s antenna.10 Ground terminals with omnidirectional antennas, such as many Global Positioning System (GPS) receivers and satellite phones, have a wider field of view and thus are more susceptible to downlink jamming from different angles on the ground.

Under severe stress situations, jamming can render all commercial [Satellite Communications, or SATCOM] and most defense SATCOM inoperable.Defense Science Board Task Force on Military Satellite Communications and Tactical Networking11

The technology needed to jam many types of satellite signals is commercially available and relatively inexpensive. Jamming can also be difficult to detect or distinguish from accidental interference, making attribution and awareness more difficult. In 2015, General John Hyten, then-commander of Air Force Space Command Space Command, noted that the U.S. military was jamming its own communications satellites an average of 23 times per month.12

Spoofing is a form of electronic attack where the attacker attempts to trick a receiver into believing a fake signal that the attacker’s device produces is the real signal it is trying to receive. Spoofing the downlink from a satellite can be used to inject false or corrupted data into an adversary’s communications systems. If an attacker successfully spoofs the command and control uplink signal to a satellite, it could take control of the satellite for nefarious purposes. Research has shown that even encrypted military GPS signals can be spoofed by a device that records the encrypted signal and rebroadcasts it with a slight delay. This specialized form of spoofing GPS signals, known as “meaconing,”13 does not require cracking the GPS encryption because it merely rebroadcasts a time-delayed copy of the original signal. Like jammers, once a spoofer is developed, it is relatively inexpensive to produce and deploy in large numbers and can be proliferated to other state and non-state actors.

Cyber Counterspace Weapons

UNLIKE ELECTRONIC ATTACKS, which interfere with the transmission of RF signals, cyberattacks target the data itself and the systems that use this data. The antennas on satellites and ground stations, the landlines that connect ground stations to terrestrial networks, and the user terminals that connect to satellites are all potential intrusion points for cyberattacks. While cyberattacks require a high degree of technological sophistication and understanding of the systems being targeted, they do not necessarily require significant resources to conduct. Cyberattacks can be contracted out to private groups or individuals, which means that a state or non-state actor that lacks internal cyber capabilities can potentially pose a cyber threat by contracting with groups of individuals that do have the necessary capabilities.

Example of a low-cost commercially available jammer. Photo from

Cyberattacks can be used to monitor data traffic patterns (i.e., which users are communicating), to monitor the data itself, or to insert false or corrupted data in the system. These different types of cyberattacks vary in terms of the difficulty and, correspondingly, technological sophistication required. A cyberattack on space systems can result in data loss, widespread disruptions, and even permanent loss of a satellite. For example, if an adversary can seize control of a satellite through a cyberattack on the satellite’s command and control system, the cyberattack could shut down all communications and permanently damage the satellite by expending its propellant supply or damaging its electronics and sensors. Accurate and timely attribution of a cyberattack can be difficult, if not impossible, because attackers can use a variety of methods to conceal their identity, such as using hijacked servers to launch an attack.

The report focuses on four specific countries that pose the greatest risk for the United States: China, Russia, Iran, and North Korea. Following these case studies, a fifth section analyzes the counterspace capabilities of other actors, including allies and partners of the United States, other nations, and some non-state actors.

China      Russia      Iran      North Korea      Others