Lacuna in the updated planetary protection policy and international law

The Planetary Protection Policy (PPP) has proclaimed the lofty ideal "All the planets, all the time." Originally formulated as Planetary Quarantine Requirements (PQR), the planetary protection policy imposed strict decontamination standards for spacecraft during the initial period of interplanetary exploration. The policy properly has been seen as a work in progress, continuously open to consideration of new data, and subject to periodic re-examination and question with a view toward improvement to better meet the goals of science. This process has led to several revisions of the PPP to improve, simplify and clarify the standards. In keeping with past practice, the policy was recently revised in light of new data and experience, and the current update is pending before the COSPAR Bureau and Council for review and approval. Specific changes to the PPP add Enceladus to the group of target bodies within the solar system subject to heightened protective measures, and modify the provisions regarding the establishment of special regions on Mars. These new updates mark another important development in the evolution of the PPP. The PQR and the PPP were based on the precept that outbound spacecraft to celestial bodies should not contaminate natural celestial environments with Earth organisms. Therefore, the policy generally requires that certain missions, particularly to target bodies that could harbor evidence of past or current alien life, take active measures to decontaminate the spacecraft. Nevertheless, recent and proposed missions demonstrate that significant gaps remain in the policy. Instead of enhancing decontamination the policy actually promotes purposely and intentionally enlarging the number of potentially contaminating Earth organisms carried by a spacecraft that could reach celestial bodies, including those bodies which are subject to active decontamination requirements. Thus, even with the new updates, the PPP may not be fully consistent with the international obligations of the Outer Space Treaty, and the continued existence of the entire PPP policy could be in jeopardy. This article discusses the flight characteristics of two specific missions, one launched and one in development, which are consistent with the PPP but nonetheless pose a substantial risk of biological contamination of celestial bodies. The manner in which the risks can be reduced is identified, and suggestions are made to close some of the gaps that remain in the PPP to comply with international law.