Icy ocean worlds remain compelling targets of interest for planetary science and astrobiology-focused missions. Past spacecraft missions such as Cassini and Galileo set out to study icy moons in the outer solar system and revealed the existence of liquid subsurface oceans at Enceladus and potentially Europa. The subsurface oceans of these moons are believed to be in direct contact with their rocky cores (Carr et al. 1998; Schubert et al. 2007, 2009) and to fulfil most of the criteria for habitability: liquid water, chemical building blocks, and energy sources (Hendrix et al. 2019, Cable et al. 2021). Data analysis also uncovered the presence of biologically essential elements, as well as simple and complex organic molecules in Enceladus (Khawaja et al. 2019; Postberg et al. 2018, 2023; Waite et al. 2017), making it a tantalizing focus for future spacecraft mission concepts (Cable et al. 2021, MacKenzie et al. 2021; 2022) Europa, meanwhile, is currently the target of the ongoing Europa Clipper (Pappalardo et al. 2024) by NASA and JUICE (Grasset et al. 2013) mission by ESA, showcasing its astrobiological potential.
In planetary exploration, analogue research on Earth habitats is of great importance (Yücel et al. 2025). Instrumentation development for space missions, improvement of analytical methods, and aiding in data interpretation can greatly benefit from analogue experimental input. Both Europa and Enceladus present several similarities with respect to their internal structure (e.g., a salty subsurface ocean in direct contact with a rocky core, an ice shell several km in thickness and tidal heating). Interesting interfaces exist in the interiors of these moons where rock, liquid water, brine or ice interact, potentially allowing material and energy gradients to exist, and on Earth, such interfaces modulate habitability (Hendrix et al. 2019). Indeed, understanding Earth’s environments, analogous to particular features of icy ocean worlds, could aid future space missions to better tailor their exploratory strategies.