Scholars argue that increased interplanetary space exploration requires a novel approach to regulation.
In the 56 years since the first moon landing, space probes have visited every planet in our solar system. Today, space exploration is entering a new phase. NASA is preparing for human missions to Mars and intends to establish the first long-term presence on the moon. At the same time, private companies such as SpaceX are launching their own space missions with the goal of making humanity a multiplanetary species.
This expansion creates new regulatory challenges that existing legal frameworks were not designed to address. In a recent article, two legal experts argue that our current national and international laws are insufficient to manage the risks and benefits of our increasingly interplanetary existence. To address these risks, they call for an internationally coordinated effort to develop an interplanetary system of risk regulation.
Looking ahead, humanity may face a wide range of interplanetary risks, including those associated with mining, settling, terraforming, and the possibility of armed conflict among spacefaring actors. Jonathan B. Wiener, a professor at Duke University School of Law, and Chase Hamilton, an associate at Akin Gump, argue that humanity’s expanding international activities create novel risks that existing space law cannot adequately address. In particular, the authors address two key space-related risks already facing humans: contamination between planets and asteroid impacts.
The Outer Space Treaty (OST) already urges parties to avoid bringing Earth-based contaminants to other celestial planets, a process known as “forward contamination.” It also directs them to avoid bringing back to Earth harmful extraterrestrial materials from other planets, known as “back contamination.” Wiener and Hamilton argue that this two-way planetary protection against harmful biological contamination should be expanded to address contamination between other planets.
Because life is plentiful on Earth and the status of life on other planets remains unknown, Wiener and Hamilton theorize that the risk of forward contamination is currently much greater than back contamination. The risks of contamination are also likely to vary across different planets. To show how scientists attempt to manage these differences, Wiener and Hamilton cite a five-point contamination risk assessment in the planetary protection policies issued by the international Committee on Space Research (COSPAR).
Even so, Wiener and Hamilton identify two challenges in addressing the risk of interplanetary contamination. First, although the OST specifically addresses “harmful contamination,” Wiener and Hamilton contend that it fails to define the term with specificity. They observe that what may cause harm to one celestial body may have little impact on another. Second, Wiener and Hamilton maintain that the efficacy of the COSPAR contamination risk assessment is undermined by the limitations on humans’ ability to identify life forms on other planets.
Wiener and Hamilton call for COSPAR to update and elaborate the planetary protection policies as the scientific knowledge about extraterrestrial life evolves. They similarly urge the current regime to fill regulatory gaps created by ill-defined key terms in the OST’s provision on interplanetary contamination and its failure to account for an additional risk scenario: contamination of life from Earth that is altered in space before returning to Earth.
Even if the existing regulations are updated, Wiener and Hamilton caution that significant enforcement challenges remain. Because COSPAR’s planetary protection policies rely on national regulatory bodies for implementation, the authors note that countries with newer or less developed space programs may struggle to enforce them effectively.
Governments must also contend with the rapid growth of private commercial space actors, which Article VI of the OST requires nation-states to supervise. Wiener and Hamilton, however, observe that the treaty does not clearly define the scope of this responsibility, leaving national governments broad discretion with little oversight in regulating private space actors.
Wiener and Hamilton suggest that interplanetary risk regulations must be designed carefully to reduce overall risk through policies that are sufficiently cost-effective to not stymie beneficial space activities. They also maintain that these policies must be updated continually in an internationally coordinated effort as new risks come to light. These principles guide their analysis of specific interplanetary risks.
Applying this framework, Wiener and Hamilton address planetary defense, which encompasses the different strategies and actions required to protect Earth from potential impacts involving asteroids and other celestial bodies. From an interplanetary perspective, planetary defense includes the prevention of harmful collision impacts between planets. Wiener and Hamilton note that while Earth is an obvious concern, future human settlements on the Moon, Mars, and elsewhere may also be vulnerable to such impacts.
Wiener and Hamilton argue that effective interplanetary risk regulation should prioritize the early identification and continuous tracking of potentially dangerous objects, careful assessment of the likelihood and severity of possible impacts, and the development and use of tools to prevent or reduce the likelihood of collisions. Building on these principles, they explain that regulatory oversight is necessary because planetary defense requires coordination, involves uncertain and technically demanding risk assessments, and may give rise to conflicts as more spacefaring actors participate in impact response efforts.
They further contend that the existing regime of international law is ill-equipped to manage planetary defense through collective action and global coordination. To overcome these limitations, Wiener and Hamilton suggest the creation of new institutions with authority to assess collision threats affecting any celestial body, evaluate missions that involve altering the movement of celestial objects, coordinate responses to potential impact risks, and oversee the use of asteroid deflection technologies to manage the tradeoffs created by human intervention.
Wiener and Hamilton conclude that, as humanity expands its sphere of influence to other planets, it is essential that institutions adopt well-designed interplanetary risk regulation to protect the interests of those on Earth and other celestial bodies.
