Tort Liability of Non-State Actors for Violations of the Outer Space Treaty

Potentially Tortious Activities in Outer Space

In the short history of human presence in outer space, several instances of questionable conduct by private actors have taken place that conceivably would have infringed the rules set out in the OST. To name a few, space objects have been launched into outer space without a governmental license, satellites have been intentionally destroyed creating a large amount of orbital debris, and spacecrafts have even crashed in celestial bodies causing “scars” and releasing biological matter. None of this conduct has resulted in civil liability for the perpetrators.

Considering these real historical examples, and also other situations likely contemplated in each norm of the OST, what follows is a compilation of ten categories of hypothetically tortious activities in outer space that may implicate non-State actors. We will then investigate whether and how these acts and omissions may be actionable in tort.

Interference with Lawful Space Activities and “Space Freedoms”

In general, meddling with legitimate space activities of third parties may be tortious. The U.S. government considers the “[p]urposeful interference with [another State’s] space systems, including supporting infrastructure” to be “an infringement of a nation’s right.” Specifically, any of the following are considered malicious cyber activities harmful to space operations: spoofing sensor data, corrupting sensor systems, jamming or sending unauthorized commands for guidance and control, injecting malicious code, and conducting denial-of-service attacks.

This type of conduct was already considered during the ratification hearings for the OST. At the time, Senator Gore asked what the liability of the U.S. Government would be under Article VII of the OST if “a private U.S. corporation engaging in satellite communications becomes very ambitious and undertakes to jam the signals of other communications systems.”

More broadly, activities that curtail the exercise of any of the four freedoms of space (exploration, use, access, scientific investigation) enshrined in Article I of the OST may be tortious and, under certain circumstances, actionable. Because all States are free to explore and use outer space and because access to all areas of celestial bodies shall be free, the necessary implication is a prohibition on States (and derivatively, other actors) to act in a manner that limits the exercise of those freedoms by others. The OST teaches us that the four freedoms of space must be exercised in accordance with international law (OST Art. I), for the benefit and in the interest of all countries (OST Art. I), and with due regard to the corresponding interests of all other State Parties (OST Art. IX). In addition, the exploration and use of outer space shall be “the province of mankind.” While these precepts are crafted as broad aspirational principles, they play a role in informing the contextual interpretation of other “harder-law” provisions. Note that “Congress [has] declare[d] that it is the policy of the United States that activities in space should be devoted to peaceful purposes for the benefit of all humankind.”

It may be argued that only States enjoy those freedoms. While the text of OST Article I attributes the freedom of exploration and use to “all States,” the freedom of access “to all areas of celestial bodies” and the freedom of scientific investigation are instead phrased generically, in the passive voice (e.g., “There shall be free access . . . ”; “There shall be freedom of scientific investigation in outer space . . . .”). This choice of words can be construed to mean that these specific freedoms are not afforded exclusively to State Parties but were meant to belong to all humankind.

Significantly, with respect to the appropriation and exploitation of space resources (as a subset of the freedom to “use” outer space and celestial bodies), both Congress and the Executive Branch have unequivocally taken the position that private entities have the right to exploit those resources. In fact, “[t]he United States considers unfettered freedom to operate in space vital to advancing the security, economic prosperity, and scientific knowledge of the Nation.”

Thus, the U.S. government understands that non-State actors do enjoy at least some of the freedoms of Article I of the OST. Taking the argument further, if private entities have the right to exploit outer space and celestial bodies, it follows that a remedy must be available to redress breaches of that right (ubi jus, ubi remedium). This remedy, by necessity, is domestic in nature because nongovernmental entities do not have direct access to the international liability mechanism of the Liability Convention (which, in Article XI.2, also recognizes that there are other venues for redress in the State members’ local jurisdictions).

Of note, one of the original draft bills of the U.S. Commercial Space Launch Competitiveness Act expressly provided for a civil action “for any action by another entity subject to United States jurisdiction causing harmful interference to its operations with respect to an asteroid resource utilization activity in outer space.” However, the fact that this provision was considered by Congress but never made it into the final law may evidence Congress’s intent not to afford a private right of action for acts that interfere with the right to extract space resources.

Placing of Large Number of Satellites in Orbit and Beyond (“Mega-Constellations”)

Hypothetical 1

A space developer prepares to launch and place in low-Earth orbit 600 communication satellites. Shortly after launching the first batch, satellite trails become noticeable in the sky, contaminating astronomical images. May an astronomy institute whose research has been impaired by the satellite trails file a suit to enjoin the developer from launching a second set of satellites? If the astronomy institute had recently invested millions of dollars in observation equipment, may it also sue for damages?

This hypothetical captures the negative impact on optical ground-based astronomy of the so-called “mega-constellations” of satellites. According to a report released in August 2020, the launch of “[e]xisting and planned large constellations of bright satellites in low-Earth orbit (LEOsats) will fundamentally change astronomical observing.”

One of the declared objectives of the United States in conducting space activities is “[t]he search for life’s origin, evolution, distribution, and future in the universe.” Thus, for the purposes of recognizing a cause of action in this scenario, it can hardly be argued that Congress is indifferent to the protection of space observation and research.

The OST norm clearly engaged here is the freedom of scientific exploration, but the freedoms of access, exploration, and use of outer space (OST Art. I), and the prohibition to release harmful contamination (OST Art. IX), may also be implicated.

Private Appropriation of Celestial Bodies and Depletion of Space Resources

Three potential sub-scenarios are covered under this group, all related to the prohibition of national appropriation of outer space “by claim of sovereignty, by means of use or occupation, or by any other means” (OST Art. II). One, a State asserting sovereignty over a celestial body (e.g., an asteroid) through the acts of a commercial space developer. In this case, the private actor could be deemed as aiding and abetting the State in the violation of the prohibition against national appropriation. Two, a private space developer, licensed by a State (e.g., a licensee operating with an FAA launching/reentry license properly issued) and extracting minerals from a celestial body pursuant to the CSLCA, occupies an asteroid completely, to the exclusion of all others. Three, that same space developer overuses and depletes the mineral resources in a given celestial body.

Hypothetical 2

After the success of a NASA-led mission to the metal asteroid Psyche, a U.S. corporation is granted a license to launch with the purpose of mining the whole surface of the asteroid. May a foreign space mining company sue to enjoin the corporation from occupying Psyche in its entirety?

Because the prohibition is directed at “national” appropriation, Article II does not (at least directly or facially) address or regulate appropriation of outer space that is not governmental. Put differently, it does not contain an express prohibition of non-State occupation in a private-property sense. However, it seems a necessary conclusion that non-State actors should not be permitted to do what States are forbidden from doing. To illustrate the point, for a State to grant exclusive rights of occupation and control over a celestial body to a “Hudson Bay company of space” would be hardly consistent with Article II. According to most academics, outer space and celestial bodies are res communis omnium as opposed to res (or terra) nullius: they are not subject to acquisition as private property while, at the same time, everyone can use them. It is important to distinguish between claiming property rights on resources extracted from celestial bodies (plausibly consistent with OST Article II) as against a claim of ownership or title over the surface or sub-surface of such celestial body (“space realty”), or, as P.J. Blount puts it, between real property claims versus claims of chattel property over extracted space resources.

Hypothetical 3

The successful bidder on a public tender to collect and sell lunar regolith and other rock materials sets up an extraction facility on the Moon. The large perimeter of the mining operation obstructs a natural passage and impedes access to certain areas of the Moon’s surface beyond the contractor’s installation. After continued operations for over a year, the mining activities have created numerous craters on the area, making impossible further extractions or investigations. May a lawsuit be filed to compel the contractor to allow others a right of way through its facility, to enjoin the continuation of the operations, and to have the operator disgorge the profits of same?

In this regard, the U.S. government has formally stated the position that it “does not view [Outer Space] as a global commons,” expressly rejecting the notion that the Moon Agreement reflects customary international law. This rebuff, in the context made, clearly refers to the provisions of Article 11 of the Moon Agreement, which states that the “Moon and its natural resources are the common heritage of mankind” and that the natural resources on celestial bodies in the solar system may not be appropriated by any person, public or private. The Executive Branch has also stated that “Americans should have the right to engage in commercial exploration, recovery, and use of resources in outer space, consistent with applicable law.” Arguably, the recognition of the right of Americans to explore, recover, and use space resources implies that the United States is ready to afford a remedy and a forum in the event that right is impaired. As shown later, the Alien Tort Statute may provide just that (but only to non-American plaintiffs). Finally, Section 10.2 of the Artemis Accords confirms the view of the United States on this subject when it states that “the extraction of space resources does not inherently constitute national appropriation under Article II of the Outer Space Treaty.”

Hypothetical 4

A corporation is granted a license to take samples from a small asteroid. The method used to extract the materials consists on blasting a projectile into the asteroid. As a result of the impact, the asteroid is largely destroyed. Is the corporation liable in tort to other private entities interested in the same samples?

While private use of space resources may not be proscribed by the OST (and it is certainly not banned under U.S. domestic law), the same may not hold true for their abuse. When outer space and celestial bodies are not subject to appropriation, and their use is to be carried out for the benefit of humankind, does the concept of waste apply to an otherwise permitted use of space resources? For instance, the Moon’s vacuum, a useful resource, may be easily disturbed, and, if destroyed by one actor, it will be destroyed for everyone. Another example would be the complete depletion of the resources of an asteroid. At a minimum, the conduct in these examples run afoul of the due regard principle of OST Article IX.

In conclusion, on the one hand, the mere appropriation of space resources by way of extraction (e.g., asteroid mining) is unlikely to be considered tortious by American courts. On the other hand, claims of private appropriation of the surface (or sub-surface) of an asteroid, or an entire area of a planet, to the exclusion of others would likely contravene international law (and, in particular, OST Article II). Also, depletion of space resources on a given celestial body may be regarded as a violation of the due regard principle or analogized with the unlawful appropriation forbidden by OST Article II.

Placing of Nuclear or Other Weapons of Mass Destruction in Outer Space

Hypothetical 5

The government signed a contract with a private provider of launching services to launch a rocket with a payload that includes the equipment necessary to perform a nuclear test on an asteroid. The contract is publicly leaked. May a member of the public file suit to enjoin the launch services contractor from launching or otherwise continuing to perform the contract?

OST Article IV prohibits the “weaponization” of outer space and allows its use exclusively for peaceful purposes. While this is a prohibition that likely only States have the capability to violate, private launchers may be the agents that actually place those weapons in orbit. Either as primary tortfeasors or by aiding and abetting the State in question, non-governmental actors engaging in these activities could be violating OST Article IV.

Failure to Assist Distressed Astronauts

Hypothetical 6

While carrying out a commercial mission on the Moon, Astronaut “A” receives a distress call from Astronaut “B,” who has been injured after her rover crashed. Astronaut “A” ignores the call, and ultimately Astronaut “B” succumbs. May the estate of Astronaut “B” bring a wrongful death action against Astronaut “A” and her employer?

Astronauts are “envoys of mankind,” and the OST grants them special protection. On Earth (at least in the United States, and generally in the common law world), generally no duty to rescue exists, and one cannot sue for personal injury or death on a theory of negligence based on a failure to provide assistance. By contrast, OST Article V creates a duty on “the astronauts of one State Party” to “render all possible assistance to the astronauts of other States Parties” while carrying out activities in outer space. Remarkably, this obligation applies beyond question to non-State actors (i.e., the individual astronauts “of one State Party”).

In addition, States are under an obligation to alert other State Parties or the U.N. Secretary-General of “any phenomena they discover in outer space or celestial bodies, which could constitute a danger to the life or health of astronauts.”

Failure to Return Space Objects

Under Article VIII of the OST and the Rescue Agreement, States retain jurisdiction over, control of, and ownership of objects launched into outer space. As a corollary, States that find themselves in possession or control of space objects belonging to other States have the obligation to return them to their rightful “owner.” In both Article VIII of the OST and Article 5.3 of the Rescue Agreement, this obligation is couched in the passive voice (“objects . . . shall be returned”), which may suggest a broad application of the precept. In my view, expanding the obligation to return space objects so as to reach private entities as well would be a stretch, given that most non-State actors will not have the capability to handle space objects. Regardless, private actors could participate or engage in a violation of this norm as agents or aiders and abettors of their State. In addition, a private space actor intentionally retaining possession of, and preventing access to a space object belonging to someone else, may well be liable for common law conversion, without the need to engage the norms of the OST.

Release of Biological Material into Outer Space or Celestial Bodies

This conduct was best exemplified in the crashing of the lunar lander Beresheet on April 11, 2019. Beresheet was a private mission undertaken by the nonprofit SpaceIL and sponsored by the Israeli Space Agency with the goal to land an unmanned spacecraft on the surface of the Moon. It was launched by a SpaceX Falcon 9 from Cape Canaveral. According to NASA “Beresheet attempted to touch down on April 11, 2019, in an ancient volcanic field known as the Sea of Serenity (Mare Serenitatis in Latin). NASA’s Apollo 17 astronauts landed near this region on Dec. 11, 1972. The team lost contact with the spacecraft shortly before expected touchdown.” The lunar lander contained a capsule with dehydrated microorganisms (tardigrades) supplied by the NGO “The Arch Mission,” which was instantly released to the lunar surface upon crashing. Apparently, The Arch Mission had willfully concealed from SpaceIL that living organisms were in the capsule. It is thought that the tardigrades survived the impact, but whether they were actually ejected outside of the capsule is unknown.

Transferring lifeforms or organic material to celestial bodies may be considered a form of “interplanetary contamination” (or “forward contamination”) contrary to the prohibition against causing harmful contamination contained in OST Article IX. In addition, such conduct may curtail the freedom of scientific investigation (OST Art. I) as it disturbs the natural conditions of unexplored celestial bodies and prevents adequate astrobiology research (e.g., exporting earthen life could invalidate life detection experiments in the celestial body being explored). Furthermore, the obligation to act in outer space with due regard of the interests of other nations may be engaged as well (OST Art. IX).

In this respect, an international standard for planetary protection has been developed by the Committee on Space Research (COSPAR). COSPAR has developed standards for “planetary protection,” such as the COSPAR Planetary Protection Policy. Space agencies, including NASA, have generally embraced it. Critically, NASA “recognizes that the 1967 Outer Space Treaty (OST) sets forth legal requirements on U.S. governmental and non-governmental entities to prevent such forward and backward harmful biological contamination.”

Creation and Dissemination of Space Debris

Space (or “orbital”) debris is defined as “all artificial objects including fragments and elements thereof, in Earth orbit or re-entering the atmosphere, that are non-functional.” It is a known threat for space activities. According to the European Space Agency, “[t]here are currently over 129 million objects larger than a millimetre in orbits around Earth.”

The negligent or willful creation and dissemination of space debris likely constitutes harmful contamination in violation of OST Article IX, infringes the due regard principle, and potentially impairs the freedoms of use and exploration of outer space to the extent that the debris damages space objects of a third party.

Disturbance to Space Historical Sites

Hypothetical 7

While extracting resources from the Moon, the lunar rover of a private space developer unintentionally traverses the Apollo XI landing site, damaging it irreversibly. May a nonprofit devoted to the preservation of space human heritage sue?

While the OST is silent with respect to human heritage in outer space, it has been argued that the obligation to conduct space activities with due regard to the interests of other State Parties as well as the prohibition of harmful interference and harmful contamination (OST Art. IX) requires respect for historical landing sites on celestial bodies. Non-profit organizations such as For All Moonkind and Open Lunar Foundation have brought awareness to the international community about the importance of preserving space historical sites and the need to rationalize human settlement on the Moon.

At the domestic level, on December 2020, Congress passed the One Small Step to Protect Human Heritage in Space Act, which represents an acknowledgment of the value and the need to protect lunar landing sites and artifacts. In its operative part, the act directs NASA to “continue to develop best practices to respect the principle of due regard and limit harmful interference with historic Apollo lunar landing site artifacts” and to include those best practices and recommendations “as a condition or requirement to contracts, grants, agreements, partnerships or other arrangements pertaining to lunar activities carried out by, for, or in partnership with [NASA].” In addition, the Artemis Accords acknowledge “a collective interest in preserving outer space heritage” and devotes Section 9 to proclaim the intention of its signatories to preserve outer space heritage.

Space Piracy

Any attacks or plundering by a private space actor to another spaceship will be considered piracy under the definition of “piracy” in Article 101 of the United Nations Convention on the Law of the Sea. The definition includes “any illegal acts of violence or detention, or any act of depredation, committed for private ends by the crew or the passengers of a private ship or a private aircraft, and directed: . . . against a ship, aircraft, persons or property in a place outside the jurisdiction of any State.” Because outer space is “outside the jurisdiction of any State,” these types of violent acts will qualify as piracy when committed therein. As noted later in this Article (infra Section V, Cause of Action Under the Alien Tort Statute), piracy is one of the offences that fall squarely under the purview of the ATS.

Redress for Harmful Activities in Space

The above hypotheticals depict situations where a non-governmental entity has behaved, is behaving, or plans to behave contrary to the norms of conduct defined in the OST. Is there any legal recourse for a person that has been adversely affected by such activities?

The first avenue is the international liability regime established by the OST and developed through the Liability Convention. Pursuant to OST Article VII, a launching State “is internationally liable” for damage caused by their space objects to another State Party’s natural or juridical persons. Thus, if “space damages” are suffered by a natural or juridical person, a State may seek redress on the victim’s behalf directly from the tortfeasor launching State. The Liability Convention makes clear though that only the State, and not the individual, may present a claim to another State under this regime. Given that private aggrieved parties do not have direct access to the international liability mechanism and that, in all likelihood, the ratification of the OST does not equal to a waiver of State immunity, should OST Article VII be interpreted as imposing an obligation on each signatory State to create domestic remedies to channel those claims? Perhaps.

In any event, the Liability Convention was not meant to be the sole remedy or forum to redress harmful conduct in outer space. This is clear from Article XI thereof, which states that the international liability regime set in the OST and the Liability Convention does not preclude “a State, or natural or juridical persons it might represent, from pursuing a claim in the courts or administrative tribunals or agencies of a launching State.” As such, the drafters of the Liability Convention were well aware of the possibility of suits in domestic courts for conduct related to space activities.

Equally important, there are significant gaps in the scenarios covered and types of damages redressed by the Liability Convention. The Liability Convention defines “damage” as death, personal injury, and property damage to the property of States, persons (individuals and entities), or International Organizations. As such, damages to the surface of celestial bodies, discharges of substances to the Moon, pollution by mega-constellations, or economic loss, are not covered by this mechanism. This fact bolsters the conclusion that the Liability Convention is not and cannot be regarded as an exhaustive or sole remedy for harmful conduct in outer space.

There is no doubt that Congress is aware of potentially tortious activities in outer space by private entities. Indeed, 51 U.S.C. § 50914(g)—relating to Commercial Space Launch Activities—provides that federal courts have exclusive jurisdiction to hear suits for death, bodily injury, or property damage or loss resulting from an activity carried out under a launch or reentry license. This provision is significant because typically tort actions may be filed in State court unless there is diversity, federal question, or some other specific grant of jurisdiction to the federal system (such as the ATS).

The contention of this study is that the gap left by the Liability Convention may be filled by domestic tort law. As we will now see, recourse may also be had against private space operators under discrete common law tort theories (public nuisance, negligence per se, waste) and the ATS.

Cause of Action Under the Alien Tort Statute

ATS in General

28 U.S.C. § 1350 (2019), also known as the Alien Tort Statute (ATS) (or the “Alien Tort Claims Act”), provides: “The district courts shall have original jurisdiction of any civil action by an alien for a tort only, committed in violation of the law of nations or a treaty of the United States.” Enacted by the First Congress in 1789 as part of the Judiciary Act, the ATS grants jurisdiction to the federal courts for tortious conduct committed against aliens when such conduct is in violation of international law (either “the law of nations” or “a treaty of the United States”).

It has been consistently said that the ATS was Congress’s response to the jurisdictional gap identified in the so called Marbois affair, when in 1784 the Consul General of France was assaulted in Philadelphia, prompting the French government to complain about the U.S. authorities’ inability to address the matter. Ultimately, the purpose of the enactment was to “avoid foreign entanglements” by providing a forum for certain international wrongs (violation of safe conducts, offenses against ambassadors, piracy), which “if not adequately redressed could rise to an issue of war.”

The ATS went largely dormant for over 190 years. Then, starting in 1980 (with the case of Filartiga v. Pena-Irala) and up until today, it has been invoked in numerous lawsuits as a tool to vindicate alleged violations of human rights and other norms of international law, including environmental strategic litigation.

The U.S. Supreme Court has grappled with the ATS on several occasions, having set the boundaries of its application in Sosa (2004), Kiobel (2013), Jesner (2018), and Nestlé (2021).

The ATS is a purely jurisdictional statute (i.e., it does not create new causes of action) that grants jurisdiction to the federal courts to hear suits for torts committed against international law to the extent recognized by the federal common law. The Supreme Court has expressly acknowledged that among those torts are (a) torts recognized as such in 1789 by Congress, namely the so called “three Blackstone offenses against the law of nations” (violation of safe conducts, offences against ambassadors, and piracy), and (b) torts in violation of norms of international law (and treaties) developed in the future as long as they are specific and have become norms of customary international law.

Simply put, the ATS does not create a new statutory tort (or “super tort”) for violation of international law. Instead, what the ATS does is to provide a federal forum to bring causes of action based on tortious acts or omissions in breach of international law norms that meet the test established in Sosa. Those “international law torts,” and the corresponding causes of action cognizable under the ATS, are either already existing under current federal common law (the three Blackstone offenses) or may in the future be recognized by the courts if there is breach of a norm of international law (customary international law or treaty of the United States) that is (a) specific so “as to support the creation of a remedy,” (b) universal, and (c) obligatory.

Elements of an ATS Cause of Action

The elements of an ATS cause of action include the following:

1. a foreign plaintiff or “alien” (per the express terms of the ATS);
2. a defendant that is either a natural person or a U.S. corporation (but not a foreign corporation, after Jesner).
3. a tort committed in violation of either the law of nations or a treaty of the United States.

In turn, only certain international torts are actionable under the ATS:

1. Those recognized at the time of enactment of the ATS (violation of safe-conducts, offences against ambassadors, piracy);
2. New international torts if they satisfy the two-step test established by the Supreme Court in Sosa:
   1. The alleged violation at the base of the tortious conduct is one “of a norm that is specific (“sufficiently definite to support a cause of action” and “so well defined as to support the creation of a remedy”), universal, and obligatory; and
   2. Allowing a particular cause of action to proceed under the ATS is a proper exercise of judicial discretion, or instead whether caution requires the political branches to grant specific authority before liability can be imposed.

While it is unclear whether the Sosa framework would apply in its entirety to an ATS cause of action based on a violation of a treaty of the United States (as opposed to a violation of the law of nations), this Article will test the space hypotheticals against both prongs of the ATS.

Moreover, there is an still another inquiry as part of the first step of the Sosa test, introduced by footnote 20 in Sosa: the international law norm allegedly violated by the defendant must be one that is capable of breach by a non-State actor (“whether international law extends the scope of liability for a violation of a given norm to the perpetrator being sued, if the defendant is a private actor such as a corporation or individual”).

Finally, as an additional element of a prima facie case when the alleged tort occurred overseas, there is also the presumption against extraterritoriality (proclaimed by the Supreme Court in Kiobel and corroborated in Nestlé), that the ATS plaintiff needs to overcome in order to succeed. In a nutshell, if the violation alleged occurred outside of the territory of the United States (more precisely, in the territory of another sovereign), then there is a presumption that the U.S. courts will not have jurisdiction unless the plaintiff can prove that the claims at issue “touch and concern the territory of the United States . . . with sufficient force to displace the presumption against extraterritorial application” in that “the conduct relevant to the statute’s focus occurred in the United States.”

Once a prima facie case is made, an ATS defendant may be able to assert defenses. In this context, defendants have typically argued the defenses of act of state (when a foreign state has been involved in the alleged tortious violation of international law), international comity, sovereign immunity, political question, and forum non conveniens.

Applicability of the ATS to Space Activities

Against this backdrop we will now interrogate the hypotheticals described in Part III above, to determine whether the five elements of a successful ATS suit can be met. As a preliminary matter, bringing an ATS claim to redress tortious conduct in violation of the norms established in the OST should align with the rationale behind the enactment of the ATS. The ATS’s intent was to provide a federal judicial forum for foreign nationals to bring tort claims for violations of the law of nations where the United States would be responsible for the failure to provide such a forum. This would be exactly the case for a violation of the OST by a U.S. corporation (or its principals) operating in outer space. If the laws of the United States do not provide a domestic remedy to the alien victim for the tort committed by the bad actor, then the international violations will be attributed to the U.S. government by application of the international liability regime of the OST and the Liability Convention. Indeed, the federal government has agreed to indemnify, with certain exceptions and limitations, their private counterparts that are users of space vehicles or providers of launch services against third-party claims for death, bodily injury, or property damage resulting from activities carried on in connection with launching and reentry operations to the extent not covered (or compensated) by the mandatory liability insurance. In addition, the House Committee on Science, Space, and Technology, confirms in its report to H.R. 2262 (which became the CSLCA) that “the federal government is ultimately the responsible party as a result of the Launch Liability Convention” and that “[t]he Launch Liability Convention, to which the U.S. is a party, places international liability for space launch and reentry accidents on the federal government.”

In Jesner, Justice Kennedy cited with approval the brief of the United States, which stated that “the function of the ATS is to ensure private damages remedies in circumstances where other nations might hold the United States accountable if it did not provide a remedy.” It seems clear that, if U.S. corporations were to commit violations of the OST, other nations may be perturbed, likely resulting in international friction. Those nations may try to hold the United States accountable for such breaches, either through the international liability regime of the Liability Convention or worse. Simply put, other State Parties to the OST are not likely to condone conduct that otherwise infringes the OST simply because it was performed by citizens of another State Party.

Ultimately, an ATS suit in these circumstances would serve the purpose that animated the Founders when enacting the ATS “to avoid foreign entanglements.” In his concurring opinion in Jesner, Justice Alito boiled down the relevant issue in that case as “whether the United States would be embroiled in fewer international controversies if we created causes of action under the ATS against foreign corporate defendants.” If we interrogate the scenarios described here against that concern, the answer is likely a resounding yes as long as the defendant is a U.S. corporation or individual. This rationale should apply with particular force in a suit brought under the treaty prong of the ATS for a violation of the OST, because there is no principled reason why State Parties should be allowed to infringe the obligations and prohibitions of the treaty through the agency of their nationals. In addition, the OST is remarkably clear in making the State Parties responsible to supervise the conduct of their citizens in outer space (Art. VI).

There is a “symbolic force” in ATS liability. An ATS lawsuit “contributes to the uptake of international human rights norms,” while a traditional tort lawsuit does not. For that reason, allowing actions to proceed under the ATS for violations of the OST by private actors would have the effect of placating the international community and avoiding foreign entanglements for the United States.

A Proper Plaintiff: Standing

Only an alien (against whom the tort has been committed) may be a plaintiff in an ATS suit. The alien plaintiff can be an individual or an entity. This meaning is hardly surprising since the purpose of enacting the ATS was to afford aggrieved foreign citizens a cause of action that could be adjudicated in the federal courts of the United States.

For some of the hypotheticals described above in the space context (e.g., release of biological material into a celestial body), it may be difficult to identify the individual plaintiff injured by the tort (the “victim” of the tort), a fact that is likely to present standing issues. It is worth noting that the minimum standing conditions of Article III of the U.S. Constitution may not be done away with by statute.

For standing purposes, the clearer cut scenarios are those involving some personal injury or property damage, such as a violation of the obligation to render assistance to distressed astronauts (OST Art. V) and the failure to return space objects (OST Art. VIII). The distressed astronaut (or the estate thereof, if the astronaut tragically perished), and the owner of the object respectively would be rightful plaintiffs. Also, when orbital debris causes physical damage to another space object, the owner of the damaged or destroyed device should be able to sue under the theory that the defendant limited plaintiff’s freedom to use, explore, or investigate outer space (OST Art. I), that the defendant explored or used outer space not in conformance with international law (OST Art. III), or without due regard for the interests of others (OST Art. IX).

On the other end of the scale, there is the tortious release of harmful contamination into outer space (OST Art. IX). Who has standing to sue when a non-governmental entity breaches that norm? Arguably, anyone has, since the exploration and use of outer space are the province of mankind (“l’apanage de l’humanité tout entière”). The Liability Convention emphasizes that the exploration and use of outer space for peaceful purposes is an interest worthy of legal protection (a “legally-protected interest” in Article III of the U.S. Constitution parlance), and, importantly, that such interest is common to all humankind. As a matter of pleading, the plaintiff will need to allege that he or she personally suffered an injury in order to satisfy the constitutional standing requirements. In our space hypothetical, it would not be enough for the plaintiff to argue that he or she has an interest in outer space being free from contamination and that the defendant, having released harmful contamination into outer space, has invaded it. Some concrete (de facto) and particularized (individual to that plaintiff) injury will need to be alleged, albeit not necessarily actual (in other words, it can be a threatened injury), economic, or tangible.

Between the two ends of the spectrum (i.e., clear, identifiable loss to the person or private property of the plaintiff, versus harm to the common interest of humankind in the peaceful exploration and use of outer space) lays a wide variety of situations where certain violations of the provisions of the OST may cause harm that is specific to the plaintiff although in a less traditional manner. Conduct impairing the freedom of access, use, or exploration of outer space (OST Art. I) that can be pinpointed to specific plaintiffs (or groups of plaintiffs) will fall under this category. For instance, a scientific institute whose Earth-based astronomic observations or astrobiology research is drastically curtailed or rendered impossible due to the effect of mega-constellations (hypothetical #1 above), or as a result of the release of biological agents in celestial bodies. Similarly, a not-for-profit organization interested in the preservation of cultural heritage in space may decide to sue a space commercial actor that disturbed a historic landing site (hypothetical #7 above). In this respect, it is settled in the standing jurisprudence that observation of the environment is a legally protected interest whose invasion meets the constitutional requirements.

Finally, a stand-alone category may be the appropriation of celestial “real estate” and resources in breach of OST Article II (prohibition of national appropriation). The OST contains no express prohibition of private or non-State (as opposed to “national”) occupation in a private property sense. However, it seems a necessarily logical conclusion that non-State actors should not be allowed to do what States are forbidden from doing. As P.J. Blount reminds us, “[S]pace is not a state of nature,” res nullius, up for grabs for whoever gets there first. It is instead the province of humankind. For that reason, “claims of real property that assert exclusive control over a spatial territory in space are likely prohibited by Article II.” The next question then is: Who can sue?

In our hypotheticals #3 (occupation, to the exclusion of others, of a whole area of celestial body) and #4 (depletion of space resource), if the defendant “space developer” were sponsored, or at least licensed, by a State, then the occupation of the celestial body potentially amounts to “national appropriation,” in which case other States may have recourse under the international liability provisions of the OST and the Liability Convention.

Now, would the disappointed space developer also have standing to sue directly— in domestic court and in tort—the first space “land grabber”? For one, the putative plaintiff does not have a property right over the celestial body, thus precluding any action for trespass. It could still take the position that the defendant has adversely affected the plaintiff’s freedom to use outer space in violation of OST Article I, thereby frustrating its legitimate expectation to exploit resources in outer space and celestial bodies. Of course, taking that position assumes that non-State actors enjoy the space freedoms enshrined in the OST, which is less than clear. The plaintiffs will have to show that they were deprived of a real and concrete opportunity to exploit that very same celestial body or space resource. All in all, it seems that such a plaintiff would face an uphill battle in proving the standing requirements in these scenarios.

A Proper Defendant

Although the text of the ATS does not limit the scope of potential defendants in an ATS action, not everyone may be sued under the statute. First, the Supreme Court held in Jesner that “foreign corporations may not be defendants in suits brought under the ATS.” Domestic corporations however may be sued. Second, foreign States may not be sued under the ATS. An action against those entities must be brought only pursuant to, and in compliance with, the Foreign Sovereign Immunities Act, and the ATS cannot be construed to constitute a blanket exception to sovereign immunity (as held in Argentine Republic v. Amerada Hess Shipping Corp). Third, the ATS is not an implied waiver of sovereign immunity by the United States. As such, a plaintiff “seeking to sue the United States must establish, independent of that statute, that the United States has consented to the suit.” In this respect, the mere ratification of the OST by the United States does not appear, at least facially, to constitute a waiver of immunity. However, the Federal Tort Claims Act (FTCA) may “act[] as a waiver of sovereign immunity in specified types of cases.” In this regard, the D.C. Circuit has held that territories beyond any state jurisdiction (Antarctica, in that case) do not fit into the “foreign country” exception to the Federal Tort Claims Act. In doing so, it relied heavily on the analogy with the OST. Nonetheless, the Supreme Court later clarified that the FTCA’s waiver of sovereign immunity does not apply to tort claims arising in Antarctica. It is to be expected that the same logic would apply to tortious acts or omissions occurring in outer space.

On the other hand, the “no sole remedy” provision in Article XI of the Liability Convention likely reinforces the proposition that State Parties have consented, or at least contemplated, the eventuality of being sued for damages in domestic court. That section states that the international liability regime set out in the OST and the Liability Convention does not preclude “a State, or natural or juridical persons it might represent, from pursuing a claim in the courts or administrative tribunals or agencies of a launching State.” In short, albeit beyond the scope of this article, it may be possible to sue the federal government for violations of the OST.

In conclusion, foreign and U.S. natural persons may be liable under the ATS as well as domestic corporations.

Ultimately, is a violator of the norms of the OST “an enemy of mankind” as pirates were considered back in the eighteenth century? The question that ATS courts need to ask, according to Justice Breyer in Kiobel, is “Who are today’s pirates?”

A Tort in Violation of the Law of Nations or a Treaty of the United States: The Sosa Framework

By its terms, the ATS requires that the claim brought by an alien sound in “tort only, committed in violation of the law of nations or a treaty of the United States.” Thus, two categories of international wrongs may support an ATS claim: one, a violation of the law of nations; and two, a breach of an international treaty ratified by the United States.

There is consensus that the term “law of nations” refers to customary international law. It is, however, less clear whether all norms of customary international law qualify for ATS purposes, as opposed to only those peremptory or jus cogens.

Despite the fact that ATS plaintiffs often allege violations of both the law of nations and a treaty in their complaints, the case law has largely ignored the treaty prong of the ATS. In fact, “it has been more difficult for plaintiffs to succeed in pleading a violation of a treaty as a basis for jurisdiction.” In addition, the majority of the Supreme Court declared in Jesner that “[b]efore recognizing a common-law action under the ATS, federal courts must apply the test announced in Sosa” without distinguishing between the law-of-nations and the treaty prong of the ATS. Ultimately, under either of those paths, “a wrong becomes an international violation within the meaning of the [ATS]” only if “the nations of the world have demonstrated that the wrong is of mutual, not merely several, concern, by means of express international accords.” For this reason, an ATS complaint alleging a violation of the OST should need to satisfy at least the second step of the Sosa test (or a modified version of it) and possibly also the specificity part of step one.

Of note, the OST enjoys a dual status as international law: it is unquestionably a treaty of the United States (since it was ratified by Congress and without any declaration or qualification) and customary international law (although it remains unsettled which of its norms have risen to the level of jus cogens). In conclusion, an ATS action under any of the space-based hypotheticals above could seemingly rely on either prong of the ATS.

Importantly, though, not all norms of international law whose violation is alleged triggers ATS jurisdiction. In Sosa, the Supreme Court developed a test to identify which

ATS claims would be recognized as a matter of federal common law, which considers: (1) Whether the alleged violation is of a norm that is specific, universal, and obligatory and (2) whether allowing a particular cause of action to proceed under the ATS is a proper exercise of judicial discretion.

The recent decision in Nestlé shows a divided approach from the Court about the future of the Sosa framework. Three justices (Justices Gorsuch, Kavanaugh, and Thomas) were inclined to either limit ATS claims to the three Blackstone torts, or openly overrule Sosa. Another three (Justices Breyer, Kagan, and Sotomayor) advocated strongly against a further restriction of the federal courts’ ability to identify violations of international law as torts subject to ATS jurisdiction. For now, and for the purposes of this Article, it is fair to assume that Sosa stands until and unless overruled.

Sosa Step #1: Violation “of a Norm That Is Specific, Universal, and Obligatory”

In Sosa, the Supreme Court held that the ATS authorizes federal courts to recognize claims for relief for torts committed in violation of the law of nations so long as the violations were of norms supported by an international consensus of the same degree as the “historical paradigms” (e.g., piracy, offenses against diplomats, violation of safe-conducts) known to the Framers. In guiding this inquiry, the Court adopted the test already defined by the Ninth Circuit in Hilao v. Marcos (In re Estate of Marcos). Actionable violations of international law must be those of a norm that is universal, obligatory, and specific.

Universal

A norm is “universal” for ATS purposes when it has become customary international law, when there is consensus among the international community about the international wrong in question, or, in the words of the Filartiga court, when the rule in question has “command[ed] the general assent of civilized nations.”

The norms contained in the OST are unquestionably “universal,” given the fact that 110 States have ratified it (and another 23 have signed it), and the broad consensus that they enjoy the status of customary international law. To that effect, the Restatement (Third) of Foreign Relations states:

The Outer Space Declaration, for example, might have become law even if a formal treaty had not followed, since it was approved by all, including the principal “space powers.” A spokesman for the United States stated that his Government considered that the Declaration reflected international law as accepted by the members of the United Nations, and both the United States and the U.S.S.R. indicated that they intended to abide by the Declaration.

Furthermore, the requirement of universal character of the norm allegedly violated does not apply to ATS actions based on breaches of a treaty. In the Sosa test, universality is only necessary as evidence that the norm has acquired the character of customary international law. For that reason, this element is unnecessary when the complaint alleges a violation of a treaty ratified by the United States, because the norm is already binding international law for the States parties thereto, including the United States.

Obligatory

The norm must be binding in international law, “rather than hortatory.” There is no question that the OST represents a binding obligation, in international law, for all the States that have ratified it, including the United States. Also, the precepts quoted above for the purposes of tort liability are “obligatory” in the sense of commanding or prohibiting certain conduct. Nowhere in the OST is it suggested that States may or may not abide by those norms at their convenience. Furthermore, the Presidential Proclamation confirming the ratification of the OST by the United States declares “that the Treaty and every article and clause thereof shall be observed and fulfilled with good faith, on and after October 10, 1967, by the United States of America and by the citizens of the United States of America and all other persons subject to the jurisdiction thereof.” It is remarkable that this proclamation calls on all citizens and other persons under U.S. jurisdiction to comply with the terms of the treaty.

Specific

The norm allegedly violated must not have less “definite content . . . than the historical paradigms familiar when [the ATS] was enacted.” (Those paradigms are the following: violation of safe-conducts, infringement of the rights of ambassadors, and piracy.) That norm has to be “so well defined as to support the creation of a federal remedy.”

Generally, courts have concluded that general principles contained in treaties or declarations are not specific enough. Flores v. Southern Peru Copper Corp. and Sarei v. Rio Tinto PLC concluded that “neither the right to life nor the right to health was sufficiently specific to form the basis for an ATS claim.” In this respect, “general statements regarding the rights to life and health [that are] are boundless and indeterminate” and simply “express virtuous goals” are not enough. In Amlon Metals v. FMC Corp., the district court found that Principle 21 of the Stockholm Declaration of Principles was not sufficiently specific because it did not “set forth any specific proscriptions, but rather refer[red] only in a general sense to the responsibility of nations to ensure that activities within their jurisdiction do not cause damage to the environment beyond their borders.”

This lack of specificity may be also attributed to a handful of precepts in the OST, namely the principle of due regard (Art. IX) and the duty to conduct activities pursuant to international law (Art. III). However, the universal character of the OST as a whole is unquestionable, given the number of ratifications and its nature of customary international law. Another important distinction exists between ATS environmental claims and a hypothetical OST-ATS claim: when dismissing environmental suits, the courts have placed significant weight on the fact that they were not willing to impinge on other sovereigns’ rights to exploit resources in their territories. This is not a concern in outer space, which is not the territory of any sovereign. Also, these courts have interpreted the “specificity” requirement as part of the inquiry regarding whether the norm allegedly violated constitutes customary international law. In other words, in rejecting the ATS environmental claims, they relied heavily on the fact that there was no consensus that the particular international environmental norms alleged were customary international law. Here, the OST is clearly customary international law.

On the other hand, the international law prohibition against nonconsensual human medical experimentation was found to be “every bit as concrete—indeed even more so—than the norm prohibiting piracy.” Likewise, genocide and war crimes have been found to be “sufficiently specific, obligatory, and universal to give rise to an [ATS] claim.”

Importantly, in this inquiry, ATS courts have placed significant weight on whether the United States has ratified the treaty containing the norm in question. For instance, the Sarei court rejected the proposition that norms of UNCLOS could be capable of sustaining an ATS suit. It reached this conclusion despite its acknowledgment that UNCLOS “may reflect customary international law that is specific and obligatory.” What carried the day was the fact that, in the court’s view, the environmental issues at stake and the norms contained in UNCLOS were “not a matter of universal concern in the same manner that jus cogens norms such as genocide, torture or crimes against humanity are” because, among other reasons, “the United States has signed but not yet ratified UNCLOS.” The opposite is true for the OST, which was signed and ratified by the United States without any declaration or reservation. With the above in mind, which norms of the OST are sufficiently “specific” as to meet Step 1 in the Sosa test?

The precepts of the OST can be grouped in three categories with respect to their specificity in describing the conduct that is either prescribed or proscribed, from more to less specific. The first group (more specific) includes the prohibition of national appropriation of outer space and celestial bodies (OST Art. II), the prohibition to place in orbit nuclear and other weapons of mass destruction (OST Art. IV), the obligation to render assistance to distressed astronauts (OST Art. V), the obligation to take steps to return space objects (Rescue Agreement Art. 5), the obligation to inform the UN Secretary-General of the discovery of dangerous phenomena (OST Art. V), the prohibition to release harmful contamination into outer space (OST Art. IX), and the prohibition to cause adverse effects on Earth by the introduction of extraterrestrial matter (OST Art. IX). In my view, these norms pass muster. In the second group, an in-between category, is the duty not to impinge on the exercise of any of the four space freedoms of access, use, exploration, and scientific investigation (OST Art. I). While these norms are phrased in very general terms, a violation thereof may be easily identified; for instance, the hypothetical of the mega-constellation that encroaches upon the exercise of the freedom of scientific exploration of outer space by an Earth-based astronomy institute. Finally, the third category of less specific precepts cover the obligation to explore and use outer space in accordance with international law (OST Art. III) and the obligation to conduct space activities with due regard of other States’ interests (OST Art. IX).

Sosa Footnote #20: Are Private Corporations Proper ATS Defendants?

There is possibly an additional element (or at least a subset of Sosa step #1), introduced by Sosa in footnote 20: that the international law norm allegedly violated by the defendant is one that is capable of breach by a non-State actor (“whether international law extends the scope of liability for a violation of a given norm to the perpetrator being sued, if the defendant is a private actor such as a corporation or individual”). As Judge Parker stated in Abdullahi v. Pfizer, “ATS claims may sometimes be brought against private actors, . . . when the tortious activities violate norms of universal concern that are recognized to extend to the conduct of private parties—for example, slavery, genocide, and war crimes.” In other words, to support an ATS cause of action against a non-State defendant, it would not be enough that the international law norm allegedly violated is universal, obligatory, and specific. In addition, that norm, by its terms, needs to extend liability to subjects other than States. As the Sosa court declared, the norms engaged in an ATS action are those certain “rules binding individuals for the benefit of other individuals [which] overlap[] with the norms of state relationships.” According to Professor Chimène Keitner, “[I]nternational law violations that do not require state action include genocide, certain war crimes, piracy, slavery, forced labor, aircraft hijacking, and acts committed in furtherance of those violations.” Yet torture amounts to a violation of international law only if committed by officials (or private actors under color of authority). Put otherwise, the international norm prohibiting torture does not extend to the conduct of private parties.

The application of footnote 20 is less than straightforward. According to Justice Kagan during the oral argument in Jesner, “The norm [for the purposes of the Sosa step 1 analysis] is the conduct, i.e., should you be financing terrorists or not? Should you commit piracy or not? Should you commit slavery, genocide, any of the other prohibited international acts against humanity?,” as opposed to “[M]ay corporations be civilly liable for violations of the law on nations or a treaty of the U.S.” In that same oral argument, Justice Breyer clarified that “sometimes the [international law] norm [allegedly violated], even though it addresses what the state’s supposed to do directly, is also telling the private actor not to do it.” Following Justice Kagan’s logic, in the hypotheticals contemplated in this Article, the norm at stake would then be, for example, “Should you release harmful contamination into outer space?” “Should you impair exploration or scientific investigation of outer space (including celestial bodies)?” or “Should you appropriate celestial real estate to the exclusion of others?”

Also in Jesner, the plurality of the Supreme Court declared that, at the time of the judgment (2018), “there [was not] a specific, universal, and obligatory norm of corporate liability under currently prevailing international law.” It also cited (seemingly with approval) the opinion of Judge Cabranes in Kiobel v. Royal Dutch Petroleum Co. interpreting “footnote 20 to mean that corporate defendants may be held liable under the ATS only if there is a specific, universal, and obligatory norm that corporations are liable for violations of international law.”

In her dissent in Jesner, Justice Sotomayor strongly disagreed with an interpretation of footnote 20 that attempts to distinguish between categories of private actors: natural versus juridical persons. In her view, footnote 20 draws the distinction between international law norms that are addressed to, and capable of violation only by, either States or non-State actors. Specifically, she noted that “whether there is sufficient consensus that, with respect to the particular conduct prohibited under a given norm, the type of defendant [i.e., State or non-State actor] being sued can be alleged to have violated that specific norm.” To illustrate the point, she first cites to the prohibition of genocide as a norm of international law addressed to State and non-State actors alike, drawing that conclusion based on the generic, non-personal language of Article II of the Genocide Convention (defining “genocide” as “any of the following acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group”). Then, for contrast, Justice Sotomayor refers to the prohibition of torture as a norm that “require[s] state action” because under Article 1 of the Convention Against Torture, torture is committed (for the purposes of the Convention and international law) when done “by or at the instigation of or with the consent or acquiescence of a public official or other person acting in an official capacity.” This is a “norm-specific inquiry” that is “likely resolved simply by considering whether the given international-law norm binds only state actors or state and nonstate actors alike.” Justice Sotomayor concluded that “international law establishes what conduct violates the law of nations, and specifies whether, to constitute a law-of-nations violation, the alleged conduct must be undertaken by a particular type of actor.”

In the OST context, Sosa footnote 20 may be dispositive in a number of instances, if we assume that it is meant to also apply to norms contained in treaties of the United States (and not only to law-of-nations precepts). If footnote 20 is interpreted as a requirement that the international law norm allegedly breached not only defines the proscribed conduct but also affirmatively extends liability to the category of defendants involved in the particular lawsuit (State actors, or private persons, either natural or juridical entities), then only a handful of norms in the OST will meet the threshold. In most instances, the OST, by its terms, imposes the obligation or the prohibition on the States. For example, the prohibition of harmful contamination of Article IX addresses State Parties pursuing studies in and exploring outer space and celestial bodies. Indeed, the very title of the OST—Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies—points in the same direction. Also, Article XIII states that “[t]he provisions of this Treaty shall apply to the activities of States Parties to the Treaty in the exploration and use of outer space, including the Moon and other celestial bodies.” The hypothetical defendant may argue that, by its very terms, the OST applies only to activities of States, as opposed to activities of non-States.

However, other precepts in the OST are crafted in the passive voice, such as the four space freedoms of use, exploration, access, and scientific investigation. Also, one obligation is directed to individuals: the astronauts of one State Party shall render all possible assistance to the astronauts of other States Parties (Art. V).

Violation of a Treaty of the United States

An ATS action for a violation of the OST may be brought under either the law of nations or the treaty prong of the statute. This is so because it is widely recognized that the norms of the OST have achieved the category of customary international law.

There are, though, particular analytical challenges in suing under the ATS for a violation of a treaty of the United States. First, given that treaties usually regulate State conduct, which treaty norms are susceptible of violation by private actors? Second, does the Sosa two-step analytical framework apply?

The answers to these two questions are not obvious, since the jurisprudence of the Supreme Court has dealt almost exclusively with claims brought under the “law of nations” prong of the ATS, and little attention has been given to the treaty prong. While some authorities indicate that a treaty needs to be self-executing in order to support an ATS claim, others go beyond and require that a private cause of action be expressly provided for in the treaty.

The starting point of the analysis (a textual analysis of the statute) is the fact that the ATS allows suits for violations of treaties of the United States (for instance, the OST) which in turn necessarily assumes that private actors (individuals, corporations) are capable of violating at least some “treaties of the United States” (or some norms thereof). The question then becomes whether all treaties are capable of violation by non-State Parties. If not all, then which ones?

Authorities

A survey of the cases invoking the treaty prong of the ATS yields inconclusive results. In the 1795 case of Bolchos v Darrel, plaintiff Bolchos, a French captain, sued Darrel, asserting that the latter had seized slaves aboard Bolchos’s ship in violation of Article 14 of the Treaty of Amity and Commerce Between the United States and France of February 6, 1778. Arguably, the treaty directly regulated State and private conduct alike when it allowed confiscation of goods aboard enemy ships, and it mandated restitution if those goods were put onboard the enemy ship before the declaration of war.

In 1907, Attorney General Charles J. Bonaparte issued an opinion in the case of the Mexican Boundary‐Diversion of the Rio Grande. Bonaparte concluded that the ATS provided a right of action and a forum to citizens of Mexico who had been injured by the actions of the American Rio Grande Land and Irrigation Company, which diverted the waters of the Rio Grande in violation of the Boundary Convention of November 12, 1889, between Mexico and the United States. Significantly, “the court did not require that the treaty in question provide for redress in the courts of the treaty parties, and there was no question as to whether the defendant was capable, as an individual human being rather than a state, of breaching the treaty.”

In Amerada Hess, a Liberian oil tanker traversing the South Atlantic, while in international waters, was bombed by the Argentinian air force in the midst of the Falkland War. The plaintiff shipping company sued the Republic of Argentina under the ATS asserting violations of international law of the sea as codified in Article 22 of the Geneva Convention on the High Seas of 1958. Of note, Amerada Hess did not deal with a private defendant, and the main finding was that, on the facts, the U.S. courts lacked jurisdiction over Argentina in application of the Foreign Sovereign Immunities Act. However, the Supreme Court grappled with whether a plaintiff may avail itself of the rights under an international treaty, which in this case prohibited the boarding or attacking of a neutral merchant ship on the high seas and mandated restitution for any damage suffered by the merchant ship as a result of the attack. The Supreme Court concluded that these provisions of the treaty did not create private rights of action for foreign corporations to recover compensation from foreign states in U.S. courts.

Upper Lakes Shipping, Ltd. v. International Longshoremen’s Association dealt with the application of the Boundary Waters Treaty of 1909 between the United States and Great Britain. When the defendant union set up picket lines around the plaintiff’s vessels at various ports in the United States and Canada, the plaintiff corporation sued the union and others for having violated the treaty provision that ensured the freedom of navigation in all navigable boundary waters for the purpose of commerce. The district court held that the ATS did not confer jurisdiction for violation of a treaty in this case because the treaty in question expressly contained a “remedy to be pursued for violations thereof by a specified tribunal” (in this case, an International Joint Commission).

Damaskinos v. Societa Navigacion Interamericana, S.A., Panama, a personal injury case for alleged unseaworthiness of a vessel, held that a treaty must confer a cause of action for its violation to attract ATS jurisdiction. The treaty in question stated simply that nationals of the United States and Greece had to be “accorded national treatment and most-favored-nation treatment with respect to access to the courts of justice and to administrative tribunals and agencies within the territories of the other Party, in all degrees of jurisdiction, both in pursuit and in defense of their rights.” The court found that provision insufficient to create any substantive rights that could be enforced.

In Valanga v. Metropolitan Life Insurance Co., an insurance company refused to disburse life insurance proceeds because an internal corporate policy precluded payments to beneficiaries domiciled behind the Iron Curtain (the beneficiary was a resident of the U.S.S.R.). The court held that such refusal did not constitute a violation of a treaty of the United States. Among other arguments, the plaintiff contended that Metropolitan’s refusal to make good on the policy constituted a breach of a tariff agreement between Lithuania and the United States. The court rejected the argument because the tariff agreement was irrelevant to the alleged breach of the insurance contract. Citing Damaskinos, it stated that the ATS “demands strict relevancy by requiring that a violation of such treaty be demonstrated.”

Dreyfus v. Von Finck stood for the proposition that only when a treaty is self-executing—when it prescribes rules by which private rights may be determined—may it be relied on for enforcement of such rights. Plaintiff asserted jurisdiction under the ATS and alleged that the taking of his property in Germany in 1938 violated four treaties of the United States. The court found that none of the treaties cited by the plaintiff conferred any private rights with regard to his property capable of enforcement in American courts. Note, however, that Dreyfus was decided at least in part based on the premise that the law of nations deals only with States and not with individuals. That conclusion was later questioned by the Second Circuit “at least insofar as it concerns individual injuries under the international law of human rights.”

Jogi v. Voges (Jogi I) was another ATS suit based on violations of a treaty, in this case, the Vienna Convention on Consular Relations. The plaintiff (an alien) alleged that his right to access to consul had been violated. According to the Jogi I court, an ATS claim under the treaty prong is viable if the treaty in question both (1) creates an individual right enforceable in court, and (2) is self-executing. The Seventh Circuit found that the Vienna Convention was self-executing and that its Article 36 afforded an implied private right of action to enforce an individual’s rights to access to consul. Two years later, the Court of Appeals withdrew its opinion in Jogi I, thus “sav[ing] for another day the question whether the ATS might also support subject matter jurisdiction in a case like Jogi’s” because “it is unclear whether the treaty violation Jogi has alleged amounts to a tort.”

More recently, the Second Circuit reaffirmed in Abdullahi its previous holding in Khulumani v. Barclay National Bank Ltd. that “[w]hether a treaty that embodies [a norm of customary international law] is self-executing is relevant to, but is not determinative of, [the] question of whether the norm permits [ATS] jurisdiction.”

Importantly, the Supreme Court in Sosa seemed to think that violations of non-self-executing treaties may not be the basis for an ATS action when it explained that “although the [International] Covenant [on Civil and Political Rights] does bind the United States as a matter of international law, the United States ratified the Covenant on the express understanding that it was not self-executing and so did not itself create obligations enforceable in the federal courts.”

Self-Executing Treaties

As seen above, numerous authorities require that a treaty be self-executing in order for a violation of its norms to be the basis of a viable ATS suit. A self-executing treaty is a treaty that becomes judicially enforceable upon ratification, as opposed to a non-self-executing treaty, which becomes judicially enforceable only when implemented through legislation. Medellín v. Texas is the seminal case on the doctrine of self-executing treaties. The question of whether a treaty is self-executing “is distinct from whether the treaty provision also creates private rights or remedies.”

Whether a treaty is self-executing may be ascertained “by looking to various indicators, including statements that are made by Congress or the Executive regarding the treaty, indeterminate language of the treaty, or, if the treaty deals with a matter within the exclusive law-making power of Congress, indicating that Congress must create implementing legislation.” Also, “[i]n recent decades, it has become common for the Senate to include a declaration stating that some or all of the provisions in a treaty are non-self-executing under U.S. domestic law.”

Filing declarations with respect to treaties was a practice in existence since the eighteenth century. For instance, the United States has filed “reservations, declarations, and understandings” when ratifying the Convention Against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment, the International Covenant on Civil and Political Rights, or the New York Arbitration Convention on the Recognition and Enforcement of Foreign Arbitral Awards. As mentioned, the United States did not file any declaration when it ratified the OST.

Moore’s Federal Practice and some courts (Jogi I, Dreyfus) interpret the treaty prong of the ATS as requiring, for the viability of the claim, that the treaty itself provide a private cause of action to individuals. This additional layer is inconsistent with the holdings of numerous appellate courts, that for an ATS action to proceed for an alleged violation of the law of nations it is unnecessary that plaintiffs establish the existence of an independent, express right of action. Indeed, there is no principled reason that justifies a higher bar when a treaty violation has been alleged.

Others have even rejected the proposition that the self-executing nature of the treaty precept should be read as a requirement. As such, according to Herz:

[A]t least two arguments support the view that ATCA allows private suits under non-self-executing treaties. First, if ATCA does not allow such suits, the treaty provision is entirely unnecessary because self-executing treaties are already actionable under §1331 “arising under” jurisdiction. Alternatively, a tort committed in violation of a non-self executing treaty should afford courts jurisdiction to hear common law claims based on that tort, even if it does not allow plaintiffs to litigate treaty rights.

Is the OST Self-Executing?

If we assume that only self-executing treaties (or self-executing provisions thereof) may allow an ATS claim to proceed, then the next step in the analysis is to ascertain to what extent the norms of the OST are self-executing. At the time of ratification, the United States did not file any declaration or understanding to limit the application or interpretation of the OST.

During the hearing before the U.S. Senate Committee on Foreign Affairs about the ratification of the OST, Ambassador Goldberg (former Justice of the U.S. Supreme Court and head of the U.S. delegation that negotiated the Treaty) indicated that OST Article I may not be self-executing but that other provisions are.

Fifty years later, the Senate’s Subcommittee on Space, Science, and Competitiveness dealt with the self-executory character of the OST during a hearing held on May 23, 2017. The discussion showed a lack of consensus as to whether the OST, or which parts of it, are self-executing. For starters, in his opening statement, Senator Ted Cruz declared that “it’s incumbent on Congress to use this 50-year anniversary of the Outer Space Treaty to properly determine our actual international obligations, to decide if specific articles in the treaty are self-executing or not,” which is nothing short of an admission that the question is far from settled. Then, witness James Dunstan, of Mobius Legal Group LLC, contended that Article VI (dealing with international responsibility) is not self-executing but other OST provisions are, such as “no nuclear weapons in space [Article IV], no military bases on the Moon or celestial bodies [Article II], and no appropriation of a celestial body [Article II].” Mr. Dunstan also argued in a prepared statement that “[t]here is a strong argument that the last two prohibitions [harmful contamination, harmful interference] are not self-executing.” Laura Montgomery, of Ground Based Space Matters, LLC, also testified to the effect that “Article VI is not, under U.S. law, self-executing, which means that it does not create an obligation or a prohibition on the private sector unless and until Congress says it does” and “Article IX of the Treaty . . . [which provides] that states’ parties to the treaty shall avoid harmful contamination of outer space and adverse changes in the environment of Earth . . . does not, in other words, apply to private actors . . . [b]ecause the harmful contamination provision is neither applicable nor self-executing.” Finally, the written statement of Professor Matthew Schaefer, of the University of Nebraska College of Law noted: “On the self-executing nature of the OST, we could debate that endlessly . . . . [T]he key point today is that the international obligation created by Article VI remains regardless of whether it is self-executing and failure to abide by it will risk foreign retaliation . . . .”

Conclusion

It appears that two types of treaty obligations may be the rightful subject of an ATS claim: First, treaty provisions that expressly and by their own terms address private conduct. Second, treaty norms that, even though directed to State acts, regulate conduct that may also be performed by individuals. Certain obligations in treaties may only be discharged by States. In other cases, though, the proscribed conduct is such that individuals or corporations are capable of performing the prohibited act. For instance, the prohibition on releasing harmful contamination to outer space under OST Article IX can be breached by States and private actors alike.

Arguably, on the one hand, allowing a generous interpretation of which treaties are covered under the ATS would promote the main purpose of the Act: avoiding the diplomatic strife that may result if the United States tolerates the impunity of bad private actors that violate the international obligations of the United States. Ultimately, why would private citizens be allowed to do what is forbidden to the States themselves? On the other hand, an argument may be made that allowing this expansive interpretation of what treaties are “ATS-material” may open the floodgates of litigation, as numerous conducts regulated in treaties are capable of being performed by individuals.

In conclusion, it appears that at least the following provisions of the OST are capable of breach by private actors and, as such, may be the subject of an ATS action: Article I (four freedoms of space), Article V (duty to assist astronauts), and Article IX (prohibition of harmful contamination). Article IV (prohibition of militarization and weaponization of outer space) and Article II (prohibition of national appropriation) may only be breached by non-governmental entities in an accessory mode (i.e., as agents or aiders and abettors of a State). Finally, even if a treaty is not directly enforceable within the United States, it still may be relevant to an ATS case as evidence of the content of customary international law (when the treaty codifies independently recognized customary international rules, as is the case with the OST).

International Repercussions to U.S. Foreign Relations (Sosa Test, Step #2)

Even after finding that the international law norm allegedly breached by the defendant is sufficiently “specific, universal, and obligatory” (Sosa Step #1), the federal courts may still exercise their “residual common law discretion” and reject an ATS claim. They will do so if hearing the claim is likely to interfere with the foreign relations of the United States. This discretion “should be undertaken, if at all, with great caution.” Other than that caution, there is no clear guidance in the jurisprudence of the Supreme Court as to how this discretion is to be exercised. Indeed, Nestlé showed a divided court with respect to the import of the second step of the Sosa test.

In our space hypotheticals, as long as the defendants are U.S. (individual or corporate) citizens, entertaining an ATS claim should not, in principle, interfere with the foreign relations of the United States. It seems unlikely that a foreign sovereign would protest because a U.S. corporation is sued in U.S. courts. In fact, allowing ATS complaints to be heard will further Congress’s policy behind the enactment of the ATS and other acts of Congress. For instance, prosecuting actions for torts committed against the Moon heritage appears consistent with the ends and goals of the One Small Step Act. In particular, Section 2(b) of the Act underscores the need for a legal framework now that “commercial enterprises and more countries acquire the ability to land on the Moon” and ties the OST principles of due regard and avoidance of harmful interference with the protection of the Apollo landing site artifacts.

Yet Plaintiffs may argue that applying the ATS to U.S. corporations operating in outer space may put them at a competitive disadvantage with respect to foreign corporations. Although beyond the scope of this study, Canadian courts would possibly consider this type of claim against Canadian companies in application of the Nevsun doctrine.

The Presumption Against Extraterritoriality

Does the allegedly tortious conduct need to occur within the territory of the United States to be actionable under the ATS? The ATS, as any other statute, applies prima facie to acts within the territory of the United States. Only when Congress has expressly authorized its extraterritorial application, or in some other very limited circumstances, will the statute apply beyond U.S. territory. This is a canon of statutory interpretation known as the presumption against territoriality. In Kiobel, the Supreme Court held that the “principles underlying” this presumption against territoriality apply to ATS suits. It also held that the presumption may be defeated if the claims “touch and concern . . . the territory of the United States,” but only to the extent they “do so with sufficient force to displace the presumption against extraterritorial application” and that “mere corporate presence” does not suffice. The stated purpose of the rule is “to protect against unintended clashes between our laws and those of other nations which could result in international discord.”

Critically, after Nestlé, ATS plaintiffs will have to “establish that the conduct relevant to the statute’s focus occurred in the United States.” In that regard, “allegations of general corporate activity—like decisionmaking—cannot alone establish domestic application of the ATS.” The Supreme Court in Nestlé applied the test for extraterritorial application of domestic laws set forth in RJR Nabisco, Inc. v. European Community, a decision issued after Kiobel but not on an ATS case. The rulings in both Kiobel and Nabisco were premised on a dichotomy between U.S. territory and foreign territory. Thus, for a finding that a law has been impermissibly applied extraterritorially, the focus of the conduct at stake must have “occurred in a foreign country.” In ATS causes of action based upon violations of the OST occurring in outer space, does the presumption bar any lawsuit because the acts did not occur in U.S. territory?

Because outer space is not the territory of any State, the answer should be “no.” Indeed, Kiobel repeatedly referred to the presumption as applying to acts within the territory of another sovereign (as opposed to anywhere outside the territory of the United States), underscoring that the raison d’être of the presumption is to avoid the United States injecting itself into another sovereign’s affairs. Nabisco, similarly, rejects the extraterritorial application of U.S. laws when the relevant facts occurred in a foreign country. Ultimately, the presumption ensures the avoidance of diplomatic strife. Following this very logic, the majority in Kiobel reconciles the fact that piracy is a paradigmatic ATS offense even though it typically occurs outside of U.S. territory, by emphasizing that the High Seas are jurisdictionally unique because they are beyond any sovereign’s territory, and, therefore, the concerns about foreign entanglements is attenuated. The same principle applies to outer space, which is neither the territory of another sovereign, nor subject to national appropriation.

Beyond Kiobel, there is authority providing support for the proposition that the ATS would apply to torts committed in the High Seas: Jansen v. Vrow Christina Magdalena (recognizing that an ATS claim would be a basis for jurisdiction for acts outside of U.S. territory, on the High Seas) and Bolchos v. Darrel (acknowledging ATS jurisdiction when the original cause arose at sea). But, with respect to Antarctica, the Supreme Court held in Smith v. United States that an action against the federal government arising in that territory was barred because Antarctica is deemed a “foreign country” for the purposes of the foreign-country exception of the Federal Tort Claims Act.

The nuance here is that, in Kiobel and Nestlé, and for ATS purposes, extraterritoriality does not mean application of U.S. law outside of the U.S. territory but into the territory of another sovereign. The High Seas, Antarctica, or outer space is not the territory of another sovereign, and, as such, extraterritoriality should not preclude an ATS action.

In conclusion, the presumption against extraterritoriality should not bar ATS actions brought for violations of the OST that occurred in outer space. This is so because outer space is, by the very clear terms of Article III of the OST, beyond sovereignty claims of appropriation. Importantly, the OST by its own nature is a treaty with extraterritorial reach: it applies extraterritorially (i.e., to conduct that occurs in outer space, the Moon, and other celestial bodies) or it does not apply at all.

Finally, if it was determined that the presumption against extraterritoriality does extend to outer space, then a court would need to determine whether on the facts of the case the particular ATS claim touched and concerned the territory of the United States with sufficient force. In our space hypotheticals, conceivably the Kiobel test could be met. First, the putative defendants are U.S. corporations by necessity (Jesner telling us that foreign corporations may not be sued under the ATS), and most likely all decisions leading to the tort are made on U.S. territory. Second, it is doubtful that any foreign State would protest the fact that U.S. courts are assuming jurisdiction. Finally, the defendants would be principal tortfeasors, as opposed to aiders and abettors, making the connection to U.S. territory even stronger.

Defenses

If an ATS plaintiff is able to make out a prima facie case, the defendant still may be able to assert defenses, such as act of state, forum non conveniens, international comity, or failure to exhaust domestic remedies. In our space hypotheticals, where the defendant is a U.S. corporation, the act of state defense could only apply when the private entity is acting as an accessory or agent to the tortfeasor State (for instance, in the case of a space commercial launcher placing in orbit weapons or other military material). Forum non conveniens will likely be of no avail in these scenarios where the tortfeasor is an U.S. corporation sued in federal court because the defendant will be at home and no other forum is more convenient than that.

With respect to international comity or political question, those would likely be disposed of at the second step of Sosa. Finally, failure to exhaust available domestic remedies does not apply to space torts when it comes to violations of the ATS, because there are no extraterrestrial courts or remedies. It may be argued though that redress under the international liability mechanism of the Liability Convention should be pursued before suing in federal court. However, the very terms of the Liability Convention (Art. XI.2) clarify that domestic relief may be pursued and is not incompatible with the international liability regime. Also, individuals do not have direct access to such a mechanism.

Finally, in the space appropriation hypothetical (private actor making a claim of property in a celestial body to the exclusion of others), a defendant may argue that the U.S. government has proclaimed that there is freedom to extract resources in outer space, that they have been issued a license, or that outer space and celestial bodies are not global commons.

Conclusion

As argued above, an action under the ATS to vindicate violations of certain norms of the OST perpetrated by commercial entities may be viable. However, such a lawsuit will no doubt be met with significant challenges. First, standing to sue could be difficult to prove, given that the damage or injury in some instances (harmful contamination or appropriation of outer space) is not individualized. Second, the specificity branch of Sosa 1 may constitute a significant hurdle as it can be argued that many of the precepts of the OST are more general principles than specific norms. Third, it is very unclear how the tenets of the footnote 20 in Sosa would be applied to extend (or not extend) the norms of the OST to private actors. Fourth, an attack based on the doctrine of self-execution of treaties is also likely to be launched by a plaintiff. Finally, it is yet to be seen whether the opinion in Nestlé ends up drastically limiting the scope of actionable torts to the three Blackstone offenses of attacks to ambassadors, violation of safe-conducts, and piracy.

Public Nuisance & Waste

Public Nuisance

May OST violations by private actors be redressed through a suit for public nuisance? Public nuisance is the “unreasonable interference with a right common to the general public.” Rights common to the general public include “such things as the right to use a public park, highway, river, or lake.” One of the criteria recognized by the Restatement (Second) of Torts to determine whether a violation of a public right is unreasonable is whether the defendant’s conduct is proscribed by a statute, ordinance, or administrative regulation. Arguably, conduct in violation of the norms of the OST fulfills this requirement.

For the purposes of standing in public nuisance there is no need that defendants or plaintiffs act in the exercise of private property rights. This is important because, as we saw earlier in this Article, there is no real property in outer space or celestial bodies.

In this analysis, the ultimate question is whether the rights and freedoms enshrined in the OST are “public rights” (rights common to the general public) for the purposes of the definition of public nuisance. From the groups of activities listed in Part III above, the following are potential candidates:

a) Placement of a high number of satellites in orbit that hampers the observations of Earth-based astronomers, which potentially violates the freedom of scientific investigation under OST Article I.

b) Certain forms of private appropriation of celestial bodies and depletion of space resources, potentially hindering the freedom to use outer space and celestial bodies (Art. I) and, arguably, violating the prohibition of national appropriation (Art. II), as well as the principle of due regard if the exploitation was conducted at the behest of a State (Art. IX).

c) Release of biological material into outer space, creation and dissemination of space debris, and disturbance of space historical sites in violation of Article IX, if we assume a public right to be free from harmful contamination in outer space and celestial bodies (i.e., a right to an “outer space environment” free from pollution).

The affirmation in Article I that the use and exploration of outer space are “the province of all mankind” militates in favor of the acknowledgment that the four space freedoms (exploration, use, access, and scientific investigation) are “rights common to the general public.” In this respect, Secretary of State Dean Rusk, when presenting the OST to the Senate for ratification, related that “[i]t was recognized [during the negotiations of the OST] that, while only a limited number of states might enter outer space, such activities could affect the well-being of all in this planet and in the earth’s environment.”

The original instances that gave rise to the tort of public nuisance involved conduct such as the blocking of a public highway or navigable stream, because the public has a right to free and unobstructed passage through the highway and the waterway. In the case of outer space, it appears that humankind as a whole has a right to its free use, exploration, access, and scientific investigation. Thus, any unreasonable interference with the exercise of those rights by members of the public amounts to a nuisance subject to abatement.

Modern courts have found that the public has an interest, which merits protection, in natural resources and the environment. In Pruitt v. Allied Chemical Corp., the district court found that plaintiffs had “a constructive property interest in the Bay’s harvestable species,” which had been allegedly damaged by the defendant’s discharge of a chemical. In Burgess v. M/V Tamano, the right at stake was the public’s “right to fish or to harvest clams in Maine’s coastal waters,” which is a “public right held by the State in trust for the common benefit of the people.” These courts found that a public nuisance occurred when a corporation damaged the marine life and curtailed the ability to exploit natural resources by plaintiffs. Arguably, activities in outer space that deplete resources or otherwise impede the exercise of the rights and freedoms enshrined in the OST may be likewise characterized, as long as the interference caused by the defendant is determined to be unreasonable.

Waste

“Waste” has been defined as the situation that “occurs when someone who lawfully has possession of real estate destroys it, misuses it, alters it or neglects it so that the interests of persons having a subsequent right to possession is prejudiced in some way or there is a diminution in the value of the land being wasted.” Parties with a protected possessory interest may sue the tenant that is committing waste for either damages or injunctive relief.

The doctrine may conceivably apply to those uses of space resources, including occupation of celestial bodies, that result in their neglect or destruction in a way that substantially injures the rights of others to use those resources in the future. The argument runs as follows: According to the OST (Arts. I and II) and customary international law, outer space, including celestial bodies, may not be appropriated to the exclusion of others, although use is permitted. This right to non-exclusive use, which includes the right to extract resources, is not unrestricted, since it has to be exercised in accordance with international law, for the benefit of all peoples (OST Preamble, Art. I) and with due regard to the interest of other States (OST Art. IX). In addition, use and exploration of outer space are the province of mankind (OST Art. I). The above norms would place all users of space resources in a fiduciary relationship with respect to the whole of humankind and future generations. Space operators may be analogized to “space tenants” who act as trustees or quasi-trustees for all humankind. They would have a right to use the space resource and to appropriate the benefits of the exploitation, but subject to a duty to keep the given celestial body that they occupy in repair, to prevent decay, and to return it unimpaired by their negligence at the end of the “tenancy.”

The principal challenge with this argument is the difficulty of the plaintiff to show that it actually holds a property interest (a subsequent right of possession or a “possibility of future possession”) over the celestial body that is being allegedly overused. On the one hand, it is unquestionable that the use and exploration of outer space are the province of mankind (“elles sont l’apanage de l’humanité tout entière” in the French text of OST Art. I). As such, any person has an interest in ensuring that waste of outer space (including celestial bodies) is not committed. However, it is less clear what rights, of a kind that may be enforced in a court of law, derive from that prerogative. At best, the individual plaintiff could argue to be the owner of a somehow contingent future interest, but even in that case most authorities deny damages or any remedy at all. In conclusion, without a property right recognized by domestic law, an action for waste of space resources will likely fail.

Negligence

Negligence in General

Does the OST create a duty of care on private actors for the purposes of tortious negligence? For instance, do commercial space developers owe others a duty to conduct their activities in outer space “in conformance with international law” (OST Art. III), or “with due regard to the corresponding interests of all other State Parties” (OST Art. IX)? Do individuals or corporations have a duty to avoid harmful contamination to outer space and to refrain from causing “adverse changes in the environment of the Earth resulting from the introduction of extraterrestrial matter” (OST Art. IX)? To the extent that the OST was to create duties on non-State actors, then the duty element of a negligence cause of action will be established and a plaintiff could simply sue for negligence in State court. That is, however, unlikely, because treaties, in general, create obligations exclusively on the signatory States and only in very limited circumstances do they create binding obligations directly enforceable against private actors. However, these international law norms may still be the source of liability for private individuals that act in a way that is inconsistent with them, through the doctrine of “negligence per se.”

Duty of Care, International Law, and Negligence Per Se

The OST “was intended to become a foundation for all future activity in outer space.” Taking this statement at face value, the standards of conduct defined in the OST should be relevant for duty of care purposes in a negligence action. The more general question is then whether a breach of customary international law or a treaty may be considered negligence per se.

The doctrine of negligence per se provides that the elements of duty and breach of standard of care may be satisfied when a defendant has violated

a legislative enactment or an administrative regulation whose purpose is found to be exclusively or in part (a) to protect a class of persons which includes the one whose interest is invaded, and (b) to protect the particular interest which is invaded, and (c) to protect that interest against the kind of harm which has resulted, and (d) to protect that interest against the particular hazard from which the harm results.

Whether the application of the doctrine will result in liability for acts or omissions inconsistent with the precepts of the OST will depend on the specific conduct at stake and the particular norm of the OST invoked by the plaintiff as defining the standard of behavior. For example, it may be that the test is easily satisfied with respect to the obligation of astronauts to render assistance to other astronauts (OST Art. V). But a court may find that the prohibition from national appropriation of outer space (OST Art. II) or the failure to notify of the discovery of dangerous phenomena (OST Art. V) do not apply to private space actors. It largely depends on who the plaintiff is and what he or she is suing for.

Applying step by step the negligence per se analysis as defined in the Restatement (Second) of Torts to the groups of hypotheticals described above in Section III, these are the results:

Legislative Enactment or Administrative Regulation

Does the OST qualify as a “legislative enactment”? To answer this question, we need first to determine how treaties are incorporated into U.S. law and whether they are considered “legislative enactments.” The starting point is that treaties are, together with the U.S. Constitution and U.S. laws, “the supreme law of the land.” They are “part of the laws of the United States and are supreme over State and local law.” However, the jurisprudence of the Supreme Court has made clear that only self-executing treaties are “equivalent to an act of the legislature.”

As such, whether the provisions of the OST can be considered “legislative enactments” hinges on whether the specific provision at stake (i.e., the analysis is not an all-or-nothing proposition about the instrument as a whole) is “self-executing.” Currently, the debate about which provisions of the OST are self-executing and which are not, is far from settled.

At least one court has dealt with a case of asserted negligence per se based on a treaty provision. In Stutts v. De Dietrich, the plaintiff argued negligence per se alleging a violation by the defendant bank of the Geneva Convention of 1925 and the Biological Weapons Convention of 1972 (among other instruments). The court rejected the argument because “those enactments provide no private right of action . . . and thus, plaintiffs are not members of a class the enactments were designed to protect.”

The district court reasoned that only those treaty norms that provide for a private right of action may satisfy the requirement of negligence per se. The court acknowledged that international treaties create private rights of action if they are self-executing, “meaning that a private right of action is explicitly provided for in the treaty or the treaty has been implemented by a U.S. federal statute.” However, the proposition that self-executing treaties are those that expressly contemplate private causes of action was rejected by the Supreme Court in Medellín v. Texas. The Stutts court also cited to Amerada Hess for the proposition that the Geneva Convention on the High Seas did not create a private right of action. A space tortfeasor may argue that, by analogy, neither does the OST. Thus, only OST norms found to be self-executing may be able to sustain a case of negligence per se.

To Protect a Class of Persons That Includes the One Whose Interest Is Invaded

Does the specific OST provision allegedly violated aim to protect a specific class of persons? The protected class could be as broad as humankind as a whole or as narrow as the class of astronauts, with other groups in between (such as the astronomic scientific community or competitor space commercial actors).

In general, the OST protects the interest of the broadest class of persons: humankind. The OST recognizes “the common interest of all mankind in the progress of the exploration and use of outer space for peaceful purposes” (OST Preamble, para. 2). It also states that “[t]he exploration and use of outer space” shall be “the province of mankind” (OST Art. I). In this respect, as mentioned above, the negotiators of the OST understood clearly that activities in outer space could affect the well-being of all in this planet and all in the Earth’s environment. Some of the acknowledged main purposes of the OST were to ensure that “outer space would be explored and developed under peaceful conditions” and that “space powers and nonspace powers alike would benefit from the peaceful exploration of outer space” so as to avoid becoming “a vehicle for transferring conflicts that exist upon earth to the broad reaches of outer space.”

As such, one key purpose of the OST when “enacted” was to protect those interests (the four space freedoms of exploration, use, access, and scientific investigation), which belong to “all mankind.” It is therefore the treaty’s purpose to protect humankind (the class) from invasions or encroachments into their interest “in the progress of the exploration and use of outer space for peaceful purposes” (OST Preamble, para. 2). The first purpose prong of the negligence per se analysis may be thus satisfied.

Shifting from the general to the particular, each individual precept of the OST may have the purpose to protect different particular classes of persons. For example, the mandate to render assistance to astronauts (OST Art. V) clearly protects the class of astronauts. Also, the freedom of scientific investigation (OST Art. I.3) protects the world’s scientific community. Remarkably, that freedom is phrased in the OST generically, in the passive voice (“[t]here shall be freedom of scientific investigation in outer space”), suggesting that this specific privilege is not afforded exclusively to State Parties, but is meant to belong to all humankind, or at least, its global scientific community as a class.

To Protect the Particular Interest Which Is Invaded

Which are the particular interests that the specific provision of the OST aims to protect? What is the type of harm that it was designed to prevent?

For instance, OST Article V was enacted with the unquestionable purpose to protect the life and physical integrity of distressed astronauts, while Article I.3 was to protect the freedom of scientific investigation of outer space. Articles I and IV were intended to safeguard the interest of all humankind in ensuring that outer space would not become a theater of war, and Article IX was to guard outer space and celestial bodies from forward contamination.

In general, there can be no question that the drafters of the OST thought that private actors engaged in space activities should abide by the norms of the OST, to the extent applicable to their conduct. This is the inescapable conclusion of the directive to the States in Article VI to ensure that activities in outer space performed by governmental and non-governmental actors are performed in accordance with the OST. The OST sets standards of conduct for State and non-State actors alike about how to behave in outer space.

Again, different precepts of the OST target different interests. If the specific plaintiff belonging to the protected class has suffered an injury related to one of those interests, then this prong of the test will have been satisfied. For instance, in the hypothetical of the mega-constellation, the Earth-based astronomer whose astronomical observation is impaired is the member of the protected class and the interest injured is the freedom of scientific investigation of outer space (OST Art. I.3).

To Protect That Interest Against the Kind of Harm That Has Resulted

What is the kind of harm the OST (or its individual provisions) is designed to protect against? For instance, Article I.3 may be construed as intended to afford protection against the impairment of Earth-based astronomical observations by the placing of mega-constellation. Article IX (duty to avoid harmful contamination) was conceivably designed to prevent the type of harm that could have materialized with the release of tardigrades in the Moon, or to avoid a potential spoliation of the Apollo XI landing site.

To Protect That Interest Against the Particular Hazard from Which the Harm Results

Let’s apply the negligence per se analysis to the Beresheet fact pattern (supra Section III.G). A plaintiff with standing (e.g., a university which spent millions of dollars and many years of work in preparing an astro­biology mission to the Moon, whose success is now compromised because of the release of the tardigrades concealed by the Arch Mission Foundation) suing for negligence will need first to prove that Beresheet owed a duty of care and that it breached it. Our hypothetical plaintiff may argue that the standard of conduct of a reasonable man in the circumstances (that is, an enterprise sending a probe to the Moon) is defined by OST Article IX, which prescribes that exploration of outer space ought to be conducted “so as to avoid their harmful contamination.” If the court were to adopt this precept as defining the standard of care, then a finding that the Arch Mission’s placing of the tardigrades in the lunar capsule and the ensuing crash violated the prescription will be conclusive of the issue of negligence. The plaintiff, of course, will still need to prove damages and causation. Also, even if the court does not adopt OST Article IX as the standard of conduct, it still may “be relevant evidence bearing on the issue of negligent conduct.”

Individual Duty to Assist Astronauts: Astronaut’s and Employer’s Liability

A particular instance of negligence arises from the duty of astronauts to “render all possible assistance to the astronauts of other States Parties” (OST Art. V). This provision creates an obligation directly on the individual astronauts. Interestingly, this duty is not geographically limited (as it is, in contrast, the State’s duty to assist, which by the terms of OST Article V is limited to landings on State territory or the High Seas). Thus, a distressed astronaut (or her estate) may sue under a negligence theory the individual astronaut that could have helped but chose not to. The argument would run like this: defendant Astronaut D had a duty, created by OST Article V, to assist Astronaut P who was in distress. Astronaut D failed to assist, and that failure caused in fact the injuries or death of Astronaut P. In a further twist to this theory, it is also conceivable that our distressed and injured astronaut plaintiff may bring an action against the defendant astronaut’s employer under either respondeat superior (vicarious liability), or directly for negligent hiring, negligent supervision, or negligent entrustment.

Jurisdiction

In any of these scenarios, where would the plaintiff start a lawsuit? While a personal injury suit would typically be filed in state court, several grants of federal jurisdiction may be at play depending on the facts of the case, such as diversity, alienage, and, of course, the ATS. Also, pursuant to 51 U.S.C. § 50914 (g), federal courts have exclusive jurisdiction to hear suits for death, bodily injury, or property damage or loss resulting from an activity carried out under a launch or reentry license.

Conclusion

The international liability regime established in the OST and the Liability Convention is neither exhaustive nor satisfactory, particularly so in light of the irruption of commercial operators in outer space. It is a mechanism not directly accessible to victims of conduct in violation of the norms of the OST, and, for that reason, it should not be the sole remedy available for redress. The fundamental legal gap resides in the fact that the current international law of space does not directly or expressly address non-governmental activities in outer space.

However, outer space should not be a “Wild West” for anyone, including private actors. Impunity cannot be an option, for numerous reasons. First, legal uncertainty is detrimental to private investment. Second, a lacking legal framework may lead to a race to the bottom in the form of unsustainable exploitation of space resources, with the added effect of widening inequalities and promoting unfair wealth distribution between space faring and non-space faring nations. Ultimately, impunity would lead to diplomatic friction, or war.

A comprehensive framework of how everyone (States and non-States) must behave in outer space should be put in place, based on the basic rules of engagement enshrined in the OST. While new regulations are developed, existing tort law theories may allow for the enforcement of the OST standards of conduct upon private actors. As discussed in this Article, traditional torts may provide redress, albeit in limited circumstances. In the United States, the most promising avenues are ATS causes of action, negligence per se, and public nuisance. The Canadian Nevsun framework may also offer responses to the challenges and could serve as a blueprint in other common law jurisdictions. Finally, civil law countries may possibly rely on the codified rules of extracontractual liability.

In any event, this shoehorning of the norms of the OST into current common law torts is imperfect and will no doubt be met with serious legal defenses. For that reason, it is a pressing need that, under the auspices of the United Nations’ Committee on the Peaceful Uses of Outer Space (COPUOS), a specific, comprehensive, and harmonized regulatory framework of tort liability of commercial actors operating in outer space be enacted or codified to address space torts.