Exploring planetary caves
In their Mars Exploration Roadmap, NASA laid out ambitious plans for sustained human missions to Mars by the 2030s. The Moon is seen as a potential springboard for missions to Mars, offering a base where resources could be produced or stored to facilitate extended space missions. The Moon became an even more attractive pit stop when lava tubes – cave- or tunnel-like structures formed within solidified lava flows – were identified. These lunar caves could provide protection from meteorite bombardment, radiation, and extreme temperature fluctuations, allowing humans to survive within them for substantial periods of time. Skylights – collapsed sections of the roof of a lava tube that have been imaged by the Lunar Reconnaissance Orbiter – could be used as entry points to the cave or tunnel within.
Before human habitation of planetary caves becomes reality, many interdisciplinary questions must be tackled – and these are categorised in a review by Judson Wynne at Northern Arizona University, USA, and colleagues from over 15 other institutions. Almost 200 questions covering topics including astrobiology, the cave environment, geology, robotics, instrumentation, and human exploration, were condensed into a high-priority list of just 53, based on surveys with 144 scientists and engineers. The questions ranged from “What lines of evidence are required to conclusively prove life existed in planetary caves?” to “How will robots sense, navigate, map, and select optimal sampling sites in complete darkness?”. The topics consistently deemed to be the highest priority were those related to robotics and instrumentation. Importantly, the team suggests that the technical developments required to support robotic missions to planetary caves, and ultimately human habitation of such caves, are achievable in the next decade – with the right financial investment and support.
The review provides a useful game plan for how to achieve human habitation in planetary caves. By involving researchers from multiple institutions and disciplines, the challenge of getting humans to Mars can be tackled in a more efficient and achievable way.
DETAILS: J. Geophys. Res. Planets (2022); doi.org/10.1029/2022JE007194