Discovery of 50km cave raises hopes for human colonisation of moon

"Using a radar sounder system that can examine underground structures, the orbiter
initially found an opening 50 metres wide and 50 metres deep, prompting
speculation that there could be a larger hollow.

This week scientists at the Japan Aerospace Exploration Agency (Jaxa) confirmed
the presence of a cave after examining the hole using radio waves.

The chasm, 50km (31 miles) long and 100 metres wide, appears to be structurally
sound and its rocks may contain ice or water deposits that could be turned into
fuel, according to data sent back by the orbiter, nicknamed Kaguya after the moon
princess in a Japanese fairytale."

See:

https://www.theguardian.com/science/...sation-of-moon