Cave on moon 'could shelter future explorers'

An Italian-led team has reported that there's evidence of a sizable cave accessible from the deepest known pit on the moon. It's located at the Sea of Tranquility, just 400 kilometres from Apollo 11's landing site.

The pit, like more than 200 others discovered up there, was created by the collapse of a lava tube.

Researchers analysed radar measurements by NASA's Lunar Reconnaissance Orbiter, and compared the results with lava tubes on Earth. Their findings appeared in the journal Nature Astronomy.

The radar data reveals only the initial part of the underground cavity, according to the scientists. They estimate it's at least 40 metres wide and tens of metres long, probably more.

"Lunar caves have remained a mystery for over 50 years. So it was exciting to be able to finally prove the existence" of one, Leonardo Carrer and Lorenzo Bruzzone of the University of Trento, wrote in an email.

Most of the pits seem to be located in the moon's ancient lava plains, according to the scientists. There also could be some at the moon's south pole, the planned location of NASA's astronaut landings later this decade.

Permanently shadowed craters are believed to hold frozen water that could provide drinking water and rocket fuel.

The findings suggest there could be hundreds of pits on the moon and thousands of lava tubes.

Such places could serve as a natural shelter for astronauts, protecting them from cosmic rays and solar radiation as well as from micrometeorite strikes.

Building habitats from scratch would be more time-consuming and challenging, even when factoring in the potential need to reinforce the cave walls to prevent a collapse, the team said.

During NASA's Apollo program, 12 astronauts landed on the moon, beginning with Armstrong and Aldrin on July 20, 1969.

Australian Associated Press