Pressurised natural caves could offer a home from home on the Moon

Imagine ahabitable colony on Mars or the Moon and the kinds of structures that come to mind are probably gleaming domes or shiny metallic tubes snaking over the surface. But with no Earth-like atmosphere or magnetic field to repel solar radiation and micrometeorites, space colonists would probably need to pile metres-thick rocks and geological rubble onto the roofs of such off-world settlements. More like a hobbit hole than .There could be another solution, however, that would offer future colonists safer and far more expansive living space than any cramped base built on the surface. Writing in , Raymond Martin, an engineer at Blue Origin, a rocket company, and Haym Benaroya, an aerospace engineer at Rutgers University, explore the benefits of setting up a Moon base inside giant geological tunnels that lie just below the lunar surface.