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Abstract EANA2026-93 |
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Safe and sustainable exploration of the solar system and icy worlds: COSPAR planetary protection policy
The COSPAR Planetary Protection Policy constitutes the principal international framework for preventing harmful biological contamination during space exploration. It provides guidance for ensuring compliance with the Outer Space Treaty, requiring States to avoid harmful contamination of celestial bodies and adverse changes to Earth’s environment resulting from extraterrestrial material. Although non-binding, the policy has evolved flexibly in response to scientific advances and remains the internationally recognized reference for planetary protection (Hedman et al., 2026; Olsson-Francis et al., 2026).
The COSPAR Panel on Planetary Protection (PPP) is responsible for developing, maintaining, and promoting the policy. The Panel currently comprises 26 international members, including representatives appointed by space agencies and experts from the scientific and engineering communities, with additional participation from ex-officio members and private-sector stakeholders. Its primary objective is to protect both the integrity of scientific investigations and Earth’s biosphere from the risks of forward and backward contamination. Forward contamination refers to the transfer of terrestrial organisms to other planetary bodies, potentially compromising the search for extraterrestrial life, while backward contamination concerns the possible risk of extraterrestrial material returned to Earth through sample-return missions. COSPAR emphasizes that planetary protection requirements must be grounded in the latest peer-reviewed scientific knowledge and should enable, rather than impede, Solar System exploration.
The PPP establishes policy objectives and requirements but does not prescribe specific technical solutions, leaving implementation to the responsible mission operators. Mission categorization depends on both target bodies and mission architectures. Planetary protection considerations for missions to the giant planets, including Juno, JUICE, and Europa Clipper, are discussed in Tobie et al. (2026).
Recent PPP activities have focused on assessing planetary protection needs across a range of Solar System destinations. No policy revisions were considered necessary for missions to small bodies or Venus (Zorzano et al., 2023). In contrast, the Panel revised lunar protection measures and examined key planetary protection knowledge gaps for robotic and future human exploration of Mars (Olsson-Francis et al., 2022; Spry et al., 2024). The PPP also evaluated JAXA’s MMX mission, to launch in 2026, assigning Category III requirements for the outbound phase and Category V unrestricted Earth return for the inbound phase (Raulin et al., 2019).
The Panel also conducted a comprehensive review of “Icy Worlds,” defined as outer Solar System moons and dwarf planets such as Pluto (see the 2026 update of the COSPAR Planetary Protection Policy), introducing a unified categorization framework based on established biological limits for life, particularly temperature and water activity (COSPAR, 2026; Doran et al., 2026). Through these continuing reviews, COSPAR seeks to ensure that planetary protection policies remain scientifically robust, proportionate and responsive to the evolving needs of space exploration (Coustenis et al., 2025).
References
-Coustenis, etal., 2025. ActaAstr. 233, 330.
-COSPAR (2026). SRT 224, 17.
-Doran, etal., 2026. Phil.Trans.A 384(2314).
-Hedman, etal., 2026. Phil.Trans.A 384(2314).
-Olsson-Francis, etal., 2026. Phil.Trans.A 384(2314).
-Olsson-Francis, etal., 2022) LSSR 36, 27
-Raulin, etal., 2019. LSSR 23, 1.
-Spry, etal., 2024). Astrobiology 24, 230.
-Tobie, etal., 2026. Phil.Trans.A. 2026; 384 (2314)
-Zorzano-Mier, etal., 2022. LSSR, 37,18.