A Roadmap for the Exploration of Enceladus

This paper provides key hypotheses to guide future missions to Enceladus for the current decadal cycle and beyond. Enceladus is a high priority target for the fields of astrobiology and planetary science because it contains the three basic ingredients for life as we understand it: organic materials, a liquid solvent, and an energy source. This prioritization is reflected in the National Academies of Sciences, Engineering, and Medicine 2023–2032 Planetary Science and Astrobiology Decadal Survey, which highlights Enceladus in the list of destinations for a NASA New Frontiers class mission and recommends an Enceladus Orbilander mission as the second priority Flagship mission. In 2021 the science definition team behind the Enceladus Vent Explorer, a concept funded under NASA's Innovative Advanced Concepts program, held three workshops to discuss high priority science for Enceladus. Resulting from these workshops was a list of investigations addressing two science goals: (a) “How has the thermal evolution of Enceladus impacted the moon's ability to sustain a liquid ocean and recycle nutrients?” and (b) “How has the astrobiological potential of Enceladus changed over time?” Herein we detail the science background, proposed hypotheses, objectives, and physical parameters for each proposed investigation. In addition, we introduce a novel approach to describe the organic state of a planetary body to facilitate the development of hypotheses related to the emergence of life and to contextualize putative biosignatures. Finally, we provide recommendations for further development of technology and research for ocean world exploration.