Liability for space debris collisions and the Kessler Syndrome (part 1)
by Scott Kerr
|It is not clear whether “space debris” is captured by the definition of space object, as either an independent space object or as a component part of a space object.|
Since that time, the exploration and utilization of space has continued to grow at a rapid rate. Today, space is frequented by both state and international organizations, and increasingly by private corporations and citizens: SpaceX frequently launches satellites into space;3 Planetary Resources is taking steps towards the commercial mining of nearby asteroids for valuable minerals;4 and Virgin Galactic will soon provide tourists the opportunity to explore the fringe of space.5
Space-based activities involve extraordinary costs and extraordinary speeds As such, space also poses the risk of extraordinary liability.
This paper discusses liability in space, particularly in relation to Articles II, III, and IV of the Space Liability Convention, which impose absolute liability or fault-based liability in certain circumstances. In particular, the notion of “fault” in the context of collisions in space is examined in relation to the Kessler Syndrome, a hypothetical but much-feared situation where a collision in space creates more space debris, resulting in a positive feedback loop. First, the Space Liability Convention is analyzed, and the issues posed by the Kessler Syndrome are presented. Second, rules of international law that may impact liability are examined. Third, we examine whether non-compliance with international best practices can be considered “fault” for the purposes of the Space Liability Convention. Fourth, other issues of liability in space are discussed, including national space legislation. Fifth, a hypothetical Kessler Syndrome is analyzed using the principles established within this paper.
The Space Liability Convention forms the basis of liability for damage caused by a space object. There are three important aspects of this sentence that must be mentioned: “damage,” “space object,” and “caused by.”
Damage is defined as: “loss of life, personal injury or other impairment of health; or loss of or damage to property of States or of persons, natural or juridical, or property of international intergovernmental organizations.”6 This is a purposefully broad definition, as the type of damage flowing from space activities can lead to unpredictable effects, including environmental damage.7
Space object is defined as: “includes component parts of a space object as well as its launch vehicle and parts thereof.”8 This definition has spurred a great deal of academic debate due to the confusion that inevitably follows when a term is defined by itself: the definition in essence states that a space object is defined as a space object, its launch vehicle, and their parts. However, the modifier “its” in “its launch vehicle” clearly references the term “space object,” and as such we may presume that a space object must be an object that utilizes a launch vehicle.
Further, it is not clear whether “space debris” is captured by the definition of space object, as either an independent space object or as a component part of a space object. There is no legal definition of space debris. The Science and Technology Subcommittee of the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPOUS) adopted a draft set of “high-level qualitative guidelines” in 2007,9 which was subsequently endorsed by the United Nations General Assembly,10 that defines space debris as: “All man-made objects including fragments and elements thereof, in Earth orbit or re-entering the atmosphere, that are non-functional.”11 This definition is not legally binding, but “reflect[s] the existing practices as developed by a number of national and international organizations.”12 The question of whether the pieces of a space object, when fragmented due to a collision, are still part of the original “space object” has yet to be addressed.
The phrase “caused by” is undefined within the Space Liability Convention. Clearly, the phrase references causation, though the applicable test for causation is not clear.
This paper examines the basis of liability under the Space Liability Convention, and in particular examines fault-based liability. Both absolute liability and fault-based liability are found in Articles II, III, and IV of the Space Liability Convention (reproduced here in full):
A launching State shall be absolutely liable to pay compensation for damage caused by its space object on the surface of the earth or to aircraft flight.
In the event of damage being caused elsewhere than on the surface of the earth to a space object of one launching State or to persons or property on board such a space object by a space object of another launching State, the latter shall be liable only if the damage is due to its fault or the fault of persons for whom it is responsible.
1. In the event of damage being caused elsewhere than on the surface of the earth to a space object of one launching State or to persons or property on board such a space object by a space object of another launching State, and of damage thereby being caused to a third State or to its natural or juridical persons, the first two States shall be jointly and severally liable to the third State, to the extent indicated by the following:
(a) If the damage has been caused to the third State on the surface of the earth or to aircraft in flight, their liability to the third State shall be absolute;
(b) If the damage has been caused to a space object of the third State or to persons or property on board that space object elsewhere than on the surface of the earth, their liability to the third State shall be based on the fault of either of the first two States or on the fault of persons for whom either is responsible.
2. In all cases of joint and several liability referred to in paragraph 1 of this article, the burden of compensation for the damage shall be apportioned between the first two States in accordance with the extent to which they were at fault; if the extent of the fault of each of these States cannot be established, the burden of compensation shall be apportioned equally between them. Such apportionment shall be without prejudice to the right of the third State to seek the entire compensation due under this Convention from any or all of the launching States which are jointly and severally liable. [Emphasis added].
Article III addresses situations where one state’s property causes damage to another state’s property.13 In such a situation, the Space Liability Convention imposes fault-based liability, in essence stating that even if one state’s space object causes damage to another space object (i.e. there is causation), the first state is only liable if it is established if the damage is due to its fault.
|Even if one state’s space object causes damage to another space object, the first state is only liable if it is established if the damage is due to its fault.|
Article IV(1)(b) and (2) together address situations where two or more states’ property causes damage to a third-party state’s property. In such a situation, the Space Liability Convention imposes fault-based liability, in essence stating that all states whose property caused damage to a third-party state’s property, and are found to be at fault for such damage, are jointly and severally liable for that damage. Notably, the legal scheme referred to above only applies to damage that occurs within space, which is commonly considered to begin at 100 kilometers above the Earth’s surface.14 In contrast, Article IV(1)(a) imposes absolute liability for such damage that occurs on the surface of the Earth or in the air.
Where fault-based liability is required, the Space Liability Convention clearly delineates “causation” and “fault” as separate tests. Fault-based liability requires an intentional act or omission. Therefore, while a state may cause damage, the state is only liable if it was their intentional act or omission caused the damage.
This raises the question as to why are different standards of liability required: absolute liability for land-and-air-based damages versus fault-based liability space-based damages? It seems likely that absolute liability is imposed where the loss of life or private property—that is, on the Earth and in the air—in order to ensure protection of private citizens. However, space is changing and is increasingly becoming the realm of private citizens and corporations, such as SpaceX, Planetary Resources, and Virgin Galactic. As such, perhaps the presumed justification for imposing absolute liability—the protection of private citizens and corporations—should be extended to space as well.
More than 21,000 orbital debris larger than 10 cm are known to exist. The estimated population of particles between 1 and 10 cm in diameter is approximately 500,000. The number of particles smaller than 1 cm exceeds 100 million.15
Even small pieces of debris can cause significant damage, as the average impact speed of space debris with a space object is 10 kilometers per second.16 As a result, space objects must constantly analyze potential collisions and, if necessary, conduct avoidance procedures. The International Space Station must conduct such avoidance procedures to avoid collision approximately once per year.17
Despite these precautions, collisions do occur. On February 10, 2009, a Russian military satellite and private communications satellite owned by a US-based company collided in orbit. Both were destroyed. The Russian satellite had been defunct since 1995, while the US satellite was still operational. The collision created at least 2,000 fragments of large space debris.18 No claim was made under the Space Liability Convention.
|Whereas domestic law normally requires causation and fault, causation and fault are not elements required in order to establish a state is liable in international law.|
The problems related to liability, causation, and fault for space-based damage are exemplified by a hypothetical, but probable and commonly-feared situation: the Kessler Syndrome (alternatively referred to as “collisional cascading”).19 In this situation, one space object (such as a satellite) collides with another space object, which causes the object to fragment into several uncontrolled pieces (referred to as space debris). The various pieces of space debris enter into various orbits, and subsequently collide with additional space objects, repeating the process and creating additional space debris. The amount of space debris quickly grows to dangerous levels, as each collision would create multiple objects which themselves would collide and create multiple objects, and would continue ad infinitum without human intervention.20
In such a situation, who is at fault based on the Space Liability Convention? In order to begin to answer this question one must look towards international law and previous instances of space objects causing damage.
International law does not mirror domestic law. Whereas domestic law normally requires causation and fault, causation and fault are not elements required in order to establish a state is liable in international law. As stated in Article 1 of the International Law Commission’s Draft Articles on Responsibility of States for Internationally Wrongful Acts: “Every internationally wrongful act of a State entails the international responsibility of that State.”21 One must only establish that there was wrongful conduct attributable to the state in order to establish the state is liable.22 This principle reflects absolute liability, which is utilized in Articles II and IV(1)(a) of the Space Liability Convention. The express inclusion of the word “fault” in Articles III and IV(1)(b) and (2) of the Space Liability Convention makes clear that the standard of liability is different in those circumstances—that there is a substantive difference between absolute liability and fault-based liability.
Customary international law is a source of international law that is applicable to all states.23 A rule or obligation of international law becomes customary international law when it satisfies two factors: 1) the state practice is sufficiently general and widespread, and 2) there is evidence of opinio juris, meaning states feel the state practice is obligatory.24 When considering whether a state practice is sufficiently general and widespread, one need not consider all states in the world, but rather only those states to which the practice might apply. In the case of space law, only a small (but growing) number of states in the world could be considered spacefaring states, and as such only the practice of these states is relevant.
As such, it is quite likely that many space-related international treaties (such as the Outer Space Treaty and the Space Liability Convention) have crystallized into customary international law.25 Arguably, even non-binding United Nations General Assembly Resolutions (such as Resolution 62/217, which endorsed the Space Debris Mitigation Guidelines) may have crystallized into customary international law; alternatively, their relative infancy suggests they have not yet had time to crystallize into customary international law. Ultimately, the principles of space liability discussed in this paper may be applicable to all states.
The Vienna Convention on the Law of Treaties26 (the “VCLT”) applies to treaties concluded between States, including the Space Liability Convention. Article 31.3 states that when interpreting a treaty one must consider the context, including: (a) any subsequent agreement between the parties regarding the interpretation of the treaty or the application of its provisions, and (b) any subsequent practices in the application of the treaty which establishes the agreement of the parties regarding interpretation.
Unfortunately for our purposes, there has only been one claim for damages under the Space Liability Convention. On September 18, 1977, the Soviet Union launched the Kosmos 954 into space, a reconnaissance satellite meant to observe ocean traffic. Though intended to orbit the Earth long-term, by December 1977 the satellite deviated from its orbit. The Soviet Union subsequently attempted to re-establish the proper orbit, causing the satellite to make erratic movements that changed its orbital altitude by up to 75 kilometers. Proper control over the satellite was lost, and the satellite was to re-enter Earth’s atmosphere. However, the satellite had a nuclear reactor core. The satellite contained a mechanism meant to launch the core into orbit (creating space debris, according to the COPUOS definition) but the mechanism failed. On January 24, 1978, the satellite re-entered Earth’s atmosphere and scattered radioactive debris over a 600-square-kilometer area of Canada.27
|Does non-compliance with a United Nations General Assembly Resolution satisfy the “intentional act or omission” requirement for fault-based liability under Articles III and IV of the Space Liability Convention?|
Under the Space Liability Convention, Canada claimed damages of C$6,041,174.70 for actual and future unpredicted expenses associated with the search and recovery mission and radioactive material. Such damages presumably flow from Article II of the Space Liability Convention, which states: “A launching State shall be absolutely liable to pay compensation for damage caused by its space object on the surface of the earth or to aircraft flight.” According to Article II, the Soviet Union was liable for the damages caused by Kosmos 954 and suffered by Canada on the basis of absolute liability. No formal proceedings followed. Instead, Canada and the Soviet Union agreed on $3,000,000 in damages, less than half of Canada’s original claim. According to VCLT Article 31.3(a), this subsequent agreement between Canada and the Soviet Union is relevant to “the interpretation of the [Space Liability Convention] or the application of its provisions.”
The discrepancy between damages claimed and damages paid likely flows from the definition of damages under the Space Liability Convention: “loss of life, personal injury or other impairment of health; or loss of or damage to property of States or of persons, natural or juridical, or property of international intergovernmental organizations.”28 The fact that the Soviet Union did pay damages reflects adherence to the absolute liability imposed by Article II of the Space Liability Convention. However, the discrepancy between damages claimed and damages paid suggests there were additional legal considerations. One or more of the following three considerations may have played a role:
The available information does not directly address these considerations;30 as such, all considerations should be entertained. For the purposes of this paper, the second consideration is most relevant: the test for causation may not have been satisfied for “unpredicted future damages” and therefore allowed the Soviet Union to avoid liability in respect of those damages. Such a conclusion seems valid, as causing a foreseeable risk (such as the risk of radioactive exposure) is generally insufficient to incur liability – instead, one must cause the harm to attract liability.31
As reported in the COPUOS’ Report of the Legal Subcommittee on its fifty-fourth session, held in Vienna from 13 to 24 April 2015, an interesting question was posed to the Legal Subcommittee by a member state (reproduced here in full):
Could the notion of “fault”, as featured in articles III and IV of the Convention on International Liability for Damage Caused by Space Objects (Liability Convention), be used for sanctioning non-compliance by a State with the resolutions related to space activities adopted by the General Assembly or its subsidiary bodies, such as Assembly resolution 47/68 on the Principles Relevant to the Use of Nuclear Power Sources in Outer Space, and the Space Debris Mitigation Guidelines of the Committee on the Peaceful Uses of Outer Space; in other words, could non-compliance with resolutions adopted by the General Assembly or with instruments adopted by its subsidiary bodies related to space activities be considered to constitute “fault” within the meaning of articles III and IV of the Liability Convention?32
It is a well-established principle of international law that internationally wrongful conduct (including acts or omissions, whether intentional or unintentional) by a state automatically attracts state responsibility and liability (though dispute settlement would require consent of each state). The International Court of Justice in Interpretation of Peace Treaties with Bulgaria, Hungary and Romania, Second Phase, Advisory Opinion33 applied this principle to treaty obligations, stating that “refusal to fulfill a treaty obligation involves international responsibility.”34 The application of this principle to the refusal to fulfill treaty obligations has since been established in numerous other instances, including arbitral tribunals.35 However, the principle has not been applied to “soft law” such as United Nations General Assembly Resolutions. Due to the very nature of such resolutions being non-binding, refusal to fulfill the obligations within should not attract state responsibility, unless the obligations contained therein have crystallized into customary international law.
The question posed to the Legal Subcommittee is different than the principle of internationally wrongful conduct. First, it must be noted that both Articles III and IV of the Space Liability Convention begin with “In the event of damage being caused…” and therefore can only be invoked subsequent to damage being suffered. Therefore, simple non-compliance with a United Nations General Assembly Resolution could not constitute “fault” as found in Articles III and IV of the Space Liability Convention. However, this does not mean that non-compliance is immaterial to the determination of fault. If the question is meant to examine how non-compliance may impact the determination of fault—as I suggest it is—then it appears the question posed to the Legal Subcommittee is actually: does non-compliance with a United Nations General Assembly Resolution satisfy the “intentional act or omission” requirement for fault-based liability under Articles III and IV of the Space Liability Convention?
Perhaps the best way to illustrate this question is by application to space debris. In 2007, the United Nations General Assembly adopted Resolution 62/217, which endorsed the Space Debris Mitigation Guidelines of the Committee on the Peaceful Uses of Outer Space (the “Space Debris Resolution”).36 These guidelines reflected the existing practices developed by national and international organizations. Guideline 1 states (reproduced here in full):
Guideline 1: Limit debris released during normal operations.
Space systems should be designed not to release debris during normal operations. If this is not feasible, the effect of any release of debris on the outer space environment should be minimized.
During the early decades of the space age, launch vehicle and spacecraft designers permitted the intentional release of numerous mission-related objects into Earth orbit, including, among other things, sensor covers, separation mechanisms and deployment articles. Dedicated design efforts, prompted by the recognition of the threat posed by such objects, have proved effective in reducing this source of space debris.
If a state were to launch a normal operation (such as placing a satellite in orbit) but intentionally and unnecessarily released space debris in the process, that state would be in violation of Guideline 1. If that space debris were to cause damage to Earth or aircraft, the question of liability is simple: the launching state would be liable for damage under Article II of the Space Liability Convention, which imposes absolute liability. However, if the space debris were to remain in space and collide with another state’s orbiting satellite, would the launching State be liable under Article III of the Space Liability Convention, which requires fault-based liability?
The answer to this question must be yes. The launching state caused damage (collision with another satellite) through an intentional act (releasing space debris.) Fault-based liability is established. The fact that the act was not in compliance with Guideline 1 is immaterial to establishing fault-based liability.
Does the same hold true when non-compliance flows from an intentional omission, rather than an intentional act? We now examine another example, this time in relation to Guideline 3 (reproduced here in full):
Guideline 3: Limit the probability of accidental collision in orbit.
In developing the design and mission profile of spacecraft and launch vehicle stages, the probability of accidental collision with known objects during the system’s launch phase and orbital lifetime should be estimated and limited. If available orbital data indicate a potential collision, adjustment of the launch time or an on-orbit avoidance manoeuvre should be considered.
Some accidental collisions have already been identified. Numerous studies indicate that, as the number and mass of space debris increase, the primary source of new space debris is likely to be from collisions. Collision avoidance procedures have already been adopted by some member States and international organizations.
|A breach of an ergo omnes obligation—such as failing to conduct avoidance procedures when it is known there is a reasonable risk of collision—would allow the “injured” state to invoke the responsibility of the breaching state.|
If a state launched a space object, such as a satellite, and later abandoned it due to completion of its mission or failure of its systems, Guideline 3 suggests the launching state should analyze available orbital data to predict potential collisions and limit the probability of a collision. But what if the launching state analyzes the available orbital data, is aware of a potential collision, but chooses not to utilize avoidance procedures—after all, the satellite is no longer of value to the State, so it has no interest in preventing damage to said satellite. Would the launching state be liable under Article III of the Space Liability Convention, which requires fault-based liability?
Once again, the answer to this question must be yes. The launching state caused damage (collision with another satellite) through an intentional omission (failing to limit the potential collision.) Fault-based liability is established. The fact that the state was not in compliance with Guideline 3 is immaterial to establishing fault-based liability.
Continuing with the above scenario, what if the State B has also analyzed orbital data and realizes there is a potential collision in the future. Perhaps this potential collision will occur one year from the present date. No damage has yet occurred. However, the launching state is unable to utilize avoidance procedures, either because of a systems malfunction or a lack of fuel. As a result of this potential collision, State B utilizes a significant amount of fuel to modify its own satellite’s orbital altitude. Can State B claim damages (for fuel costs and lost satellite productivity) against the launching state for non-compliance? Is the launching state at fault?
The answer to the above question must be no. The launching state caused damage to State B (fuel costs and lost satellite productivity) due to non-compliance (failing to limit the potential collision), but that non-compliance was not intentional. If it were, then it would be considered an intentional act or omission, and non-compliance would be immaterial. The heart of the issue rests with the analysis of whether an intentional act or omission occurred that caused the damage, not whether the intentional act or omission was in compliance with United Nations General Assembly Resolutions. Even an intentional act or omission that is in compliance with such Resolutions could lead to fault-based liability.
This is not to say that non-compliance has no impact on a fault-based liability analysis. Non-compliance may be used to establish that the damage was foreseeable, thereby precluding the launching state from claiming the damage was too remote. The Space Debris Resolution (and other United Nations General Assembly Resolutions) set the expectations for space-faring states, and failure to adhere to such expectations should not absolve a state from liability—an event cannot be too remote when the widely-followed international guidelines directly contemplate such an event.
Finally, the use of the word “sanction” in the question posed to the COPUOS Legal Subcommittee is extremely interesting. The relevant section of the question states: “Could the notion of ‘fault’ as featured in articles III and IV of the [Space Liability Convention]…be used for sanctioning non-compliance by a State with the resolutions related to space activities adopted by the General Assembly or its subsidiary bodies...” This is interesting in that it appears to be an attempt by a member state to utilize the Space Liability Convention for enforcement of the expectations set in regards to prominent issues such as space debris and the use of nuclear power in space.
It is not clear how such sanctioning would work in practice. Articles III and IV of the Space Liability Convention cannot be invoked until damage has occurred. However, if these international best practices have crystallized into customary international law (as it is suggested they have, or may soon), then the guidelines of the Space Debris Resolution could be ergo omnes obligations—meaning obligations each state owes to the international community.37 For example, perhaps Guideline 3 has become an ergo omnes obligation to conduct avoidance procedures if there is a reasonable risk of collision. A breach of an ergo omnes obligation—such as failing to conduct avoidance procedures when it is known there is a reasonable risk of collision—would allow the “injured” state to invoke the responsibility of the breaching state.38 Theoretically, this is possible, but full analysis is outside the scope of this paper.