A Roadmap for the Exploration of Encelad

Enceladus is a high priority target for the fields of astrobiology and planetary science given that 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 new flagship mission this coming decade after a Uranus Orbiter and Probe. In 2021 the science definition team behind the Enceladus Vent Explorer, a concept funded under NASA’s Innovative Advanced Concepts award, held three workshops at the Jet Propulsion Laboratory to discuss high priority science that could be achieved over several missions to Enceladus. A product of these workshops was a list of investigations and their flow down to measurements at Enceladus, addressing two science goals: 1) "How has the thermal evolution of Enceladus impacted the moon's ability to sustain a liquid ocean and recycle nutrients?" and 2) "How has the astrobiological potential of Enceladus changed over time?" Critically, this set of investigations was not designed to fit a particular mission architecture, but rather to serve as a framework to guide the development of successive mission concepts outlined in the 2023 Planetary Science and Astrobiology Decadal Survey and beyond. Here, we discuss the goals, objectives, and physical parameters for each proposed investigation, and we review the science background and motivation for each. In addition, we introduce a novel approach to describe the abiotic organic state of a planetary body to facilitate the development of hypotheses related to the emergence of life. Finally, we provide recommendations for further development of technology and research. This paper aims to provide hypotheses that can guide future or ongoing mission concepts to Enceladus as well as other ocean worlds including Ceres, Europa, and Titan.