Filling the Void: Why Existing International Law Is Not Suited to Mitigating Space Debris

Michael Williams
Vol. 42 Associate Editor

Space and the sea have long been paralleled, each seen as a type of res communis. There has been a push to try to understand the former through a similar lens as the latter. Space, however, provides new and complex issues that do not lend themselves well to being approached through existing frameworks. One such issue forthcoming is addressing the fear of the Kessler syndrome[1]. The Kessler syndrome, also known as ablation cascade or collision cascading, is a theoretical scenario in which a high density of space debris pollution increases the density of space debris as objects collide. As objects collide, more objects are produced generating a positive feedback loop and the likelihood of collisions increases exponentially. The fear is that as the density of space debris in low earth orbits (LEO) is increased, our ability to access space is diminished. Rockets traversing in a LEO can be rendered inoperable, or even destroyed, by pieces of debris no larger than golf balls. This fear has risen drastically as states, such as China beginning in 2007, have begun testing anti-satellite missiles which turn one item of space debris into several thousands.[2] The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies applies international law to space, but current international law – absent a new treaty – is insufficient to address the Kessler syndrome.[3] As it currently stands, soft law, customary international law, and existing treaties do not sufficiently address the issue of space debris.

The strongest argument for a soft law approach to space debris mitigation is the Space Debris Mitigation Guidelines, drafted by the Committee on the Peaceful Uses of Outer Space and endorsed by the United Nations General Assembly in 2007.[4] As part of these guidelines, member states are encouraged to utilize rockets that limit debris produced during normal operations and that any manmade object placed in LEO should only reside there so long as they remain operational and should be removed from orbit in a controlled fashion following termination of operation. As these requirements are all soft law, none of them are mandatory and member states are encouraged to comply on their own initiative. This approach fails to solve the issue for the same host of reasons that soft law has proven largely insufficient to address large scale tragedies of the common issues. Spacefaring member states have no incentive to comply, no penalty for noncompliance, and, perhaps more uniquely, the technology is still undeveloped that allows for full compliance. The recently signed Artemis Accords, however, holds that NASA and member states shall act in a manner that is consistent with the Space Debris Mitigation Guidelines, but it remains unclear to what extent member states will regulate the rapidly growing number of space fairing corporations.[5]

Customary international law faces several hurdles when addressing this issue and ultimately stumbles, proving insufficient. When drafting the United Nations Convention on the Law of the Sea (UNCLOS), there were thousands of years of seafaring to look to for what the existing customary law was at that time.[6] This is not the case with spacefaring, and parallels that can be established – if any – do not provide a strong enough foundation to build on. The Debris Mitigation Guidelines could either be a codification of customary international law in 2007 or could have become customary international law through practice and opinio juris since endorsement. It is unlikely that it codified customary international law as there is such a short window of time and so few states participated in this process of space debris mitigation before 2007. Equally unlikely is that it has become customary international law since 2007. Customary international law requires the practice of states engaged in the action – a small number here – but there has been hardly any compliance with the guidelines beyond verbal promises and guarantees. There has been zero opinio juris on the subject, unsurprising given the lack of state practice. Even if we viewed the Debris Mitigation Guidelines as binding member states through customary international law, this would again fail to address the debris left in space by corporations.

The Space Liability Convention, in conjunction with Article 31 of the Vienna Convention on the Law of Treaties, could be seen as addressing the issue of manmade space debris, but this stretches the bounds of treaty interpretation to its uttermost limits.[7] There has only been one claim under the Space Liability Convention so it can hardly be argued there is sufficient subsequent practice.[8] The definitions contained within the Space Liability Convention have, to some academics and scholars, been viewed as covering space debris. This interpretation is only possible due to the wide array of tracking of space debris and its origins.[9] Absent being able to understand where space debris originated it would be impossible to assign liability to the launching state or party. Even with tracking, fault-based liability hardly addresses space debris that is the result of a true accident. The Outer Space Treaty and the Registration Convention, the two other major treaties in the international space law regime create a patchwork framework that is nearly too vague to be usable.[10]

To truly address this issue, and others, in this new frontier, a treaty of the magnitude of UNCLOS is needed. A treaty of this scale is necessary, compared to a mere framework convention, to protect the rights of all mankind, including nations who have not yet ventured into space. To truly address the issue, such a treaty would need to hold member states strictly liable for the acts committed by private entities within their borders. As with natural resources in the high seas, we cannot let the first nations to reach space pollute it beyond usability before other nations are able to partake as well. Space, and access to it, must be a resource for all mankind.


[1] Kessler Syndrome is named for NASA scientist Donald Kessler, who first proposed the concept in 1978 in response to fears generated by exploding derelict Delta rockets generating shrapnel clouds. See Micrometeoroids and Orbital Debris (MMOD), Nat’l Aeronautics and Space Admin. (Aug. 6, 2017), https://www.nasa.gov/ centers/wstf/site_tour/remote_hypervelocity_test_laboratory/micrometeoroid_and_orbital_debris.html

[2] See Liane Zivitski, China wants to dominate space, and the US must take countermeasures, Defense News (June 23, 2020), https://www.defensenews.com/opinion/commentary/2020/06/23/china-wants-to-dominate-space-and-the-us-must-take-countermeasures/.

[3] See Treaty on Principles Governing the Activities of States in the Exploration and Use

of Outer Space, Including the Moon and Other Celestial Bodies, Jan. 27, 1967, art. I, T.I.A.S. 6347

[4] Comm. On the Peaceful Uses of Outer Space, Space Debris Mitigation Guidelines of the Committee on the Peaceful Uses of Outer Space, U.N. DOC. ST/SPACE/49, at 1 (2010), http://www.unoosa.org/pdf/publications/st_space_49E.pdf

[5] See Guoyu Wang, NASA’s Artemis Accords: the path to a united space law or a divided one? The Space Review (Aug. 24, 2020), www.thespacereview.com/article/4009/1

[6] U.N. Convention on the Law of the Sea, opened for signature Dec. 10, 1982, 1833 U.N.T.S. 397

(entered into force Nov. 16, 1994).

[7] Convention on International Liability for Damage Caused by Space Objects, Mar. 29, 1973, 24 U.S.T. 2389, T.I.A.S. No. 7762,

[8] The claim was by Canada against the Soviet Union for $6 million dollars in 1978 as a result of Soviet satellite Cosmos 954, equipped with a nuclear reactor, crashing in northern Canada. http://thebrief.muls.org/who-is-liable-for-accidents-from-outer-space. The possibility of claims under the Space Liability Convention arose in response to NASA’s Skylab falling to Earth in Western Australia, but no formal state-based claims were made. See Melissa De Zwart, With China’s space station about to crash land, who’s responsible if you get hit by space junk?, Phys Org (Mar. 29, 2018), https://phys.org/news/2018-03-china-space-station-responsible-junk.html?deviceType=mobile#!

[9] NASA, for instance, tracks over 500,000 pieces of space debris, both meteoroid and man-made, traveling up to 17,500 mph. See Space Debris and Human Space Craft, Nat’l Aeronautics and Space Admin. (Sept. 26, 2013), https://www.nasa.gov/mission_pages/station/news/orbital_debris.html

[10] For an interesting discussion on this vague framework, the loopholes it creates, and possible solutions, see Trevor Kehrer, Closing the Liability Loophole: The Liability Convention and the Future of Conflict in Space, 20 Chicago J. of Int’l L. 178, (2019).

The views expressed in this post represent the views of the post’s author only.

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