Further updates to the Committee on Space Research Planetary Protection Policy for missions to Icy Worlds

Recent discoveries have underscored the potential habitability of outer Solar System bodies like icy moons and dwarf planets. Such discoveries have elevated these bodies to high-priority targets for future astrobiology missions. However, the exploration of these environments necessitates a review and update of existing Committee on Space Research (COSPAR) planetary protection policies in view of new discoveries and to be more encompassing. A recent study by Doran et al. (Doran et al. 2024 Life Sci. Space Res. 41, 86-99. (doi:10.1016/j.lssr.2024.02.002)) proposed modifications to the COSPAR Planetary Protection Policy. Here, members of the COSPAR Panel on Planetary Protection (PPP) update those proposals based on additional community input garnered since that publication. Updates include (i) a refined definition of Icy Worlds, (ii) establish Ceres as an Icy World in addition to others under this new definition, (iii) the creation and explanation of the two-stage probability calculation for Icy Worlds, and (iv) ensuring that samples returned from an Icy World follow the same six-question framework used for small bodies in the current policy to determine whether they require restricted or unrestricted return. By incorporating critical updates, we aim to ensure the responsible exploration of these potentially life-bearing worlds while safeguarding their pristine state for future scientific investigation. The input presented in this paper will be used to make final proposals for changes to the COSPAR Policy regarding Icy Worlds by the PPP. This article is part of the theme issue 'Planetary Protection for sustainable space exploration'.