SWF PREPRINT Security, Policy and Legal Challenges of Planetary Defense


Christopher D. Johnson

Posting date:

September 27, 2023




Potentially Hazardous Near-Earth Objects (NEOs), including both asteroids and comets, pose serious risks to human and environmental security on Earth. International arrangements such as the International Asteroid Warning Network (IAWN) and the Space Mission Planning and Advisory Group (SMPAG) exist as coordinating mechanisms to detect, characterize, and assess NEO threats and to discuss and share information on possible ground and space-based threat responses and mitigation measures. However, the international political and legal environment is inadequate to deal with NEO threats. While some elements of international law, including space law, provide broad guidelines, necessary clarity is lacking. The international legal and political order does not have in place adequate safeguards, mechanisms for action, the clear delineation of roles, rights, and responsibilities at the international level to respond to a NEO threat. Additionally, a number of stressors on rational decision-making exist and would degrade the quality of NEO threat responses. Stressors on the quality of decisions and actions in response to a NEO threat include the incentive to wait for further data about the NEO, a conflicting incentive to take immediate action, and bold steps so as to satisfy constituents immediately and to feel some amount of control over the situation. Public distrust, misinformation, disinformation, and conspiracies are all also likely and will degrade public reactions and stakeholder decisions. A number of steps can be taken now, while the NEO threat remains hypothetical yet likely. These steps are warranted so as to assure the best possible response when a real, actual NEO threat emerges.


asteroid, comet, international law, militarization, Near Earth Object, NEO, planetary defense, space law, outer space, United Nations, weaponization


Christopher Johnson, "Security, Policy and Legal Challenges of Planetary Defense", SWF Preprint PP23/07, 2023.

Last updated on October 31, 2023