Space and Security

Kazuto Suzuki
Professor, Hokkaido University

China's ASAT (anti-satellite attack) test in 2007 sparked a focus on space security. However, cogent discussions and analyses available on this issue are limited in number, and the significance of the issue has yet to be understood in Japan. Meanwhile, the creation of a "space force" advocated by President Trump has been approved by Congress, and space security issues are evolving daily, with India conducting an ASAT test in March 2019. Japan cannot be indifferent to these developments. The National Defense Program Guidelines for FY 2019 and beyond (the 2018 NDPG) approved by the Cabinet in December 2018 has positioned space as a new security domain alongside with cyberspace and the electromagnetic spectrum. Although there prevails a recognition that space is vital for Japan's national defense, 1 no clear direction has so far been indicated --- defend what, and how and why.

1. "Space for Security" and "Security of Space"

The confusion that often arises around discussions on space security issues is due to our failure to understand well the relationship between "space" and "security." The 2018 NDPG argues that "capabilities of information collection, communications, and positioning should be strengthened by use of space," while "a space situational awareness (SSA) system" should be developed. Although these are all concerned with space security, they differ greatly in what they defend, what measures they adopt, and what they aim for. Some clarification may be needed.

The acquisition of space capabilities for defense purposes of information collection, communications, and positioning is space security in the sense that it is a "means" for enhancing ground defense capabilities by using space.2 It is a "means" that will enable ground troops to conduct effective combat actions by: detecting and analyzing threats by information gathering capability; maneuvering units and sending efficient instructions by communications capability; and accurately identifying the positions of enemy and friendly forces by positioning capability. Thus, "space for security" is utilized by a state to: defend its territories; employ military means on the ground to that end; and ultimately defend itself and repel enemy forces. In other words, rockets and artificial satellites can be considered "enablers" for the state to improve its military capabilities on the ground.

Space security as a "means" or "space for security" depends greatly on each country's security strategy and the nature of its defense equipment. Support from space systems would be essential for any country to do what the United States is doing, i.e., deploy troops globally; pay attention to events everywhere in the world; and efficiently operate equipment such as drones and cruise missiles. The loss of such space systems would make it difficult even for the United States to achieve its security strategy. Similarly, China and Russia have become increasingly dependent, if not more so than the United States, on their space systems. Increasingly, India is following the same path to China. On the other hand, Europe, Canada, and Japan --- unlike the former three --- have implemented global deployment of troops in the form of dispatching peacekeeping troops. Their security strategies do not assume any large-scale military operations. They also operate unmanned aerial vehicles like drones, which, however, do not play a decisive role in their national security. They also need space systems, but are not as dependent on them as are the United States, China and Russia. Many states, including developing countries, do not have a security strategy based on the use of space. They lack strong interest in "space for security." As for Japan, the 2018 NDPG states that "the use of artificial satellites is indispensable for the implementation of cross-regional operations," not for individual unit operations. It confines the necessity of satellites to the implementation of cross-regional operations.

The SSA system as mentioned in the 2018 NDPG is not necessary for space security as a "means" but for space security as a "purpose," or for the "security of space."3 As already said, space systems have become indispensable for modern security, and their proper functioning has important implications for security strategies. Meanwhile, what matters here is the fact that space systems are extremely vulnerable. Ordinarily, they are designed to be as light in weight as possible, because the deployment of an artificial object in the Earth's orbit requires launching against the Earth's gravity. (The lighter a satellite is in weight, the larger quantity of fuel it can carry, which will prolong satellite lifespan, and the more equipment it can carry as well.) Therefore, it is highly likely that satellites are crippled by an external impact or attacks using electromagnetic waves.

Moreover, in space, not only intentional attacks but also unintentional collisions can occur. Numerous space debris exist in space such as rocket fairings, defunct satellites and fragments of man-made objects, in addition to meteorites and asteroid fragments. These debris exist in the Earth's orbit, travelling at a speed of 7.9 km/s (28,000 km/h). If a satellite collides with these debris, its function will be irrevocably damaged.

Such intentional and unintentional destruction of satellites will create more debris, and threaten space safety. In addition, the resulting deterioration of the orbital environment will have a great impact not only on space systems for security but on socio-economic activities using satellites. Our daily life already heavily relies on various services provided by space systems --- weather forecasts by meteorological satellites; mapping and navigation services on smart phones using positioning satellites; and services associated with agriculture and land use, disaster prevention, and financial transactions, using earth observation satellite data.

Thus, in the modern world, space systems play an extremely significant role in both security strategies and socio-economic activities. Preserving the functions of space systems and maintaining the orbital environment safe are beneficial not only for national security but for the international community as a whole. "Security of space" is beneficial to global interests as well as to human interests beyond the state boundaries.

2. Space as a War Fighting Domain

However, there exists an intractable question. As space systems become increasingly important for both security strategies and socio-economic activities, when a conflict arises, initial attacks on enemy's space systems will decisively reduce its war potential, and disturb its socio-economic order. This means that space systems could be a very "rewarding" target for attack in a conflict.

Again as already mentioned, space systems are extremely vulnerable in their structure. Consequently, it is difficult to protect them from hostile forces' attack, while even a slight impact may cause critical damage to them. In 2007, China in its ASAT test launched a missile from the ground and shot down a defunct satellite. There are other options available to do the same: laser irradiation from the ground or the use of a killer satellite designed to cripple an enemy satellite by an intentional collision. The crippling of satellites by such kinetic attacks is considered effective from the viewpoint of military strategy. Not only China but also the United States and Russia possess the capability to shoot down satellites. In March 2019, India shot down its own satellite MICROSAT-R and became the fourth ASAT-capable country in the world.

These ASAT tests create serious problems in space. Kinetic destruction of satellites is bound to produce a huge amount of debris. As described earlier, space debris are travelling at high speed in space, and if a satellite collides with them, it will be seriously damaged. The collision itself will also produce numerous debris, which in turn will present threats to other satellites --- a so-called cascade of debris. This is called the "Kessler Syndrome" after the name of Donald J. Kessler, a NASA scientist who pointed out the phenomenon. Thus, there is a risk that a large amount of debris pollutes the Earth's orbit as a result of chain collision of debris, and space may thereby become unsuitable for safe use. However, destroying satellites and thereby generating large amounts of debris is an act that would increase the risk of collision with debris even for the countries that destroy satellites.

Rather, more concern is now growing over non-kinetic satellite attacks.4 When communicating between satellites and the ground; receiving GPS signals; or viewing images of reconnaissance satellites, radio waves are exchanged between the ground and satellites. If, radio waves are therefore cut off, the operators on Earth will be unable to get access to his satellite operated by himself, and its functions will be lost. Such an electronic countermeasures technique is called "jamming." Yet, non-kinetic attacks are not jamming alone. "Spoofing" is another electronic countermeasures technique that feeds in false data in radio waves the adversary uses for the receipt of satellite-based GPS signals to obtain necessary information to, among other things, confirm his actual position. The adversary will be led to misidentify information and will fall into confusion. Another method to interfere with satellites is called "dazzling," which gives a strong stimulus to the camera or sensor of a reconnaissance satellite and paralyzes its functions. Such non-kinetic attacks will make it possible to aim at enemy satellites not only from the ground, but also from friendly satellites in orbit. Among still other non-kinetic attacks are cyberattacks on the satellite control system to hijack a satellite by means of hacking, and attacks to disable ground-based satellite attitude control systems.

Countermeasures available to address these attacks are quite limited, and it is also difficult to identify attackers responsible for damages. The question of attribution related to the demolition of space systems is accompanied by peculiar difficulties. The SSA system can monitor the movement of space debris, but it is incapable of detecting debris less than 10 cm in diameter. Therefore, if the performance of a satellite is degraded by some kinetic / non-kinetic attack, it will be difficult to judge whether the degradation is due to a collision with debris or to any intentional attack.5 In the event of a conflict, space systems will become a "rewarding" target and be readily subject to attack.

Furthermore, in space, not only security satellites but many satellites destined for socio-economic activities are also in orbit. Recent progress in small satellite technology has made it possible to develop, manufacture and launch satellites at a low cost. As a result, developing countries, colleges and universities, and private corporations that were not involved in space development in the past have one after the other entered the field and are promoting the use of space for technology development, education, and commercial purposes. Since these new entrants to space development often place the highest priority on launching and operating satellites, they are not well aware of the use of space for security purposes. They are likely to lack preparedness for protecting their satellite control programs from cyberattacks, and to neglect the management of radio frequency for satellite control.6 And even these civil satellites, once hacked and hijacked, could be placed on a particular orbit to collide with a target military satellite under the disguise of an accident.

For a long time, space has been regarded as a "sanctuary" that should be used "exclusively for peaceful purposes." However, as its aspect of "space for security" is now more emphasized, space is no longer monopolized by the few technologically advanced countries, but has become a domain where developing countries and universities can freely enter. In this sense space is now extremely "congested." An attack on an enemy's space systems by the use of space is now deemed "rewarding." In response to these changes, the United States has come to recognize that space has evolved into a "war fighting domain."7 "Security of space" is now considered important to utilize "space for security."

3. Is Deterrence Possible in Space?

To deter hostile attacks under traditional security mechanisms, it is a prerequisite to occupy or control a certain space in the forms of homeland defense, spheres of influence, or sea or air control, and to eliminate hostile forces entering these spaces, thereby suppressing their attacks. But as far as space is concerned, the concept of spatial domination does not hold. Space as common heritage of humanity is acknowledged by the Outer Space Treaty that came into effect in 1967, while it is physically quite difficult to shoot down all enemy rockets launched into space. All objects in space are in the Earth's orbit and cannot stay in one place. Even if, therefore, we define a particular part of space as an extension of our airspace, it is almost impossible to remove space objects from there. International agreements, on the other hand, such as the UN Principles on Remote Sensing allow countries to take satellite images of other countries from the sky above. Meanwhile, a satellite on a geostationary orbit that travels at the same speed as the Earth's rotation, it appears to ground observers motionless above the airspace. It, therefore, gains certain spatial attributes that justify its exclusive use by the owner. (Exclusive use of a geostationary orbit slot for a communication satellite is permitted based on the regulations and agreements of the International Telecommunication Union.)

Thus, since space is a domain where geographic domination is not practicable, it is quite hard to work out a security strategy for space as in other terrestrial domains. What is most difficult in this context is how to introduce the concept of "deterrence." In space, as mentioned earlier, attribution of a kinetic or non-kinetic attack is anything but easy --- even if attacked, retaliation will be unlikely, unless the perpetrator is identified. Consequently, instead of deterrence by punishment that is based on the preventive effect of the threat of assured retaliation, preference is given to "deterrence by denial" that aims to reduce the effect of the adversary's attack to the minimum and makes his attack costly, thereby nullifying it. "Deterrence by denial," however, primarily intends to make the adversary give up attacks. Two conflicting countries, for example, must demonstrate a considerable capability of mission assurance to deter each other from making "rewarding" attacks on each other's space systems, attacks which are bound to deprive them of military capabilities. But cost to build such a capability could be enormous. Non-kinetic attacks, on the contrary, are advantageous in terms of cost, and almost free from the effect of "deterrence by denial."

Furthermore, even if attribution is identified, reliance on space systems widely varies from country to country. Therefore, when one country wants to retaliate for attacks on its own space systems, it is difficult to retaliate in an "eye for eye" manner, because it may be that the hostile country does not depend on space systems. For example, North Korea does not possess a missile defense system, but it has rockets needed to carry objects into space, as well as missiles that can reach 2000 km in altitude. So, if North Korea could attack the space systems of the United States or Japan by launching missile from the ground, and cripple US and Japanese satellites, an equivalent retaliation would not be available for either of the allies --- because North Korea has no active satellite and its military operations are barely dependent on space systems. The only way to deter North Korean attacks is to direct retaliation against its military assets other than space-related.

Needless to say, in the relationship between the United States, China, Russia, and India, all of which have ASAT capabilities and highly (but not equally) rely on their own space systems, a certain deterrent effect is anticipated, because they have the capabilities to attack one another's space systems. When, India, therefore, conducted an ASAT test in March 2019, Prime Minister Modi declared that "India has become a space power," and that it would be capable of deterrence in space.8 However, space deterrence strategies have not yet matured enough to acquire robust stability, and the asymmetry of reliance on space systems remains intact.

For this reason, space deterrence is fundamentally "cross-domain" deterrence. In other words, space attacks will be retaliated to by conventional military forces. According to the Tallinn Manual that argues the possibility of a military response to cyberattacks and measures available under international law, it is stipulated that only in such cases as the violation of state sovereignty or serious damages or casualties, a state is in a position to exert the right to use conventional weapons against cyberattacks.9 But this does not represent NATO's official views on cyber deterrence but those of international law scholars in NATO member states. At present there is no equivalent to the "Tallinn Manual" regarding space deterrence. The Woomera Manual Group, led by the University of Adelaide in Australia, and the MILAMOS (Manual on International Law Applicable to Military Uses of Outer Space) Group of Experts based at McGill University in Canada are currently discussing how space warfare is to be positioned in international law. They are aiming at coming up with some type of manual in the next few years. The two groups are deliberating on whether a space object is subject to state sovereignty, and whether retaliation for attacks on the object by exercising the right of self-defense is an "inherent right of states to individual or collective self-defense." Their discussions have so far not reached any definite conclusion.

Even if a "cross-domain" retaliatory attack is acknowledged as the exercise of the right of self-defense, it is mandatory to clarify how much retaliation is appropriate for what kind of attack. While it is not hard to identify a kinetic attack by missiles from the ground as clearly an intentional attack, if, on the other hand, satellites collide with each other and are destroyed, it may be difficult to classify the event as an accident or as an intentional attack. Likewise for jamming, it will be difficult to judge on the spot whether it is perpetrated intentionally or is due to some kind of defect or mistake. Furthermore, it is also difficult to assess how much loss such an attack would cause, and in particular, whether it would create significant disturbances and obstacles endangering human life. A retaliatory attack is not necessarily bound to ensure the "proportionality" between the damages suffered and the punitive damages awarded, but excessive retaliation may lead to the escalation of conflicts, which could become uncontrollable. It is not easy to clarify what level of retaliation is appropriate for what kind of damage. The Woomera Manual Group and the MILAMOS Group of Experts mentioned above may be discussing these issues, but it will take them time to come up with a conclusion.


Space systems are now essential to both security and to socio-economic activities, but their vulnerability and attribution difficulties subject them to kinetic and non-kinetic attacks and make them hard to protect. Due to the nature of space, traditional deterrence mechanisms do not work there, and for the time being, space security efforts will be focused on developing collision avoidance mechanisms using the SSA system and mission assurance mechanisms in preparation for the loss of space system functions.

With progress in small satellite technology, many commercial ventures and developing countries have taken part in space development, which will accordingly flourish more. As a result, space will be more congested than ever before. Under such circumstances, kinetic attacks that will produce space debris and non-kinetic attacks to cripple satellites by means of jamming will not only jeopardize space security but will also have a great impact on the socio-economic activities of humanity. As a consequence, the international community should establish new rules for space activities, and create an environment to help maintain the situation where space systems not only for military purposes but also for socio-economic purposes can continue operations.

Meanwhile, the making of international space rules has failed to demonstrate smooth progress to date. International coordination for the rule making is fatally hampered by the difficulty in making rules associated with "space for security," or more specifically, by the question of the deployment in space of an anti-ballistic missile defense system as part of missile defense. Unless this situation is overcome, "security of space" will not be established. In recent years, space development experts have defined "security of space" as a space safety issue, arguing that it should be distinguished from "space for security" (a security issue), and that an international agreement should be developed on, first of all, "space safety."10

Thus, the issue of space security is still evolving and no effective space security system has so far been established. If space becomes a "war fighting domain" where military force is exerted, an enormous volume of space debris stemming from this will cause a large-scale contamination of space, affecting the military use of space as well as a wide range of socio-economic activities. In order to avoid this worst possible scenario, it is urgently necessary to establish a space governance system as a global commons that should transcend the egoism of individual states, and to ensure "space safety" at the least.

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