Protecting astronauts and their equipment once they leave Earth’s magnetic cocoon is one of the central challenges of sustained lunar and Martian exploration.

The lunar surface in particular is an unforgiving place: without an atmosphere or magnetosphere, it is continuously bombarded by powerful solar and cosmic radiation, and endures some of the most intense temperature swings in the Solar System—from blistering highs of about 121 °C in sunlight to frigid lows near –146 °C in darkness.

In permanently shadowed polar regions, temperatures can plummet to around –240 °C. On top of that, a steady rain of micrometeorites erodes and sandblasts the surface. Any long-term human presence must therefore find shelter from radiation, thermal stress, and hypervelocity dust impacts rather than try to withstand them directly on the surface.

Ancient volcanic activity on the Moon and Mars has left behind lava tubes that are now seen as promising locations for future base camps, offering natural protection beneath the surface. Skylights, collapsed sections of tube ceilings, and long sinuous rilles identified in orbital imagery hint at extensive subsurface voids, but images alone cannot reveal which tubes are intact or suitable for habitats, making direct robotic exploration essential despite the harsh conditions and restricted access.