Cave on the Moon: What this discovery means for space exploration

• Scientists have confirmed the presence of a cave on the Moon, not far from the site of the first lunar landing 55 years ago. This discovery can, in the future, provide astronauts with a welcoming habitat on the Moon.

The finding

• A study titled ‘Radar evidence of an accessible cave conduit on the Moon below the Mare Tranquillitatis pit’ established the presence of a moon cave at the Sea of Tranquillity, a sprawling lunar mare large, dark, basaltic plains on its surface.
• Situated 400 kilometres from where astronauts Neil Armstrong and Buzz Aldrin landed on the Moon in 1969, the cave is roughly 45 metres wide and up to 80 metres long, having an area equivalent to 14 tennis courts.
• While the existence of lunar caves has been theorised for over 50 years, this is the first time the entry point of a cave has been discovered.
• Analysed by photos taken in 2010 by NASA’s Lunar Reconnaissance Orbiter (LRO) spacecraft of this area, known to house the deepest known pit on the moon. They concluded that the pit was the entry point to a cave created by the collapse of a lava tube, a tunnel formed when molten lava flows beneath a field of cooled lava.
• In contrast to craters which are bowl-shaped and the result of asteroid or comet strikes, pits appear as massive steep-walled depressions. At least 200 such pits have been discovered, of which 16 are believed to have formed from collapsed lava tubes, resulting from volcanic activity formed over a billion years ago.

Protecting humans from harsh lunar conditions

• The Moon is exposed to solar radiation 150 times stronger than Earth, with NASA stating that the lunar surface heats to about 127 degrees Celsius during the day, and cools to around -173 degrees Celsius at night.
• However, caves such as the one recently discovered, harbour stable average temperatures of around 17 degrees Celsius. They would also potentially shield human explorers on the Moon from the dangers of radiation, and micrometeorites. This, scientists believe, could make them a viable spot to establish a future lunar base, or an emergency shelter.
• That being said, the depth of such caves could present a challenge with regards to accessibility. They may also carry risks of potential avalanche and cave-ins.
• Further research is required to understand and map the properties, particularly the structural stability of the caves, which could be done using ground-penetrating radar, robots or cameras. To become completely viable habitats, caves would need systems to monitor movement or seismic activity, as well as safety zones for astronauts to take shelter in the event of a cave collapse.