Carbon dioxide ice can be stored in deep, dark lunar craters

Image: Possible locations of frost deposits on the dark bottoms of craters near the Moon’s south pole. (NASA’s Goddard Space Flight Center)

This is good news for future manned lunar missions. After water, carbon is perhaps the most important resource on the Moon. It can be used to produce rocket fuel, biomaterials and steel.

In the craters around the icy poles of the Moon, all kinds of volatile matter can accumulate. Although the Moon does not have an atmosphere, and therefore not much water, water and carbon is regularly supplied by comets and (micro) carbonaceous meteorites.

Thus many of the molecules formed in this way eventually disappear into space, but the molecules that accidentally end up in deep pits around the moon’s poles can be deposited in place like ice. Due to the lack of sunlight, temperatures are so low that the pits act as “cold traps”.

water ice

Data from the Diviner Lunar radiometer experiment shows that temperatures around the Moon’s poles are low enough to trap carbon dioxide molecules. In theory, large amounts of carbon dioxide could accumulate here, but whether this is really the case or not, remains to be seen. What is certain is that another NASA lunar probe in 2009 detected carbon dioxide in a plume of material that exploded after a rocket stage (intentionally) hit the moon’s south pole.

The total area of ​​CO2 cold traps around the south pole of the Moon is about 200 square kilometres. By comparison, the water ice traps cover approximately 14,000 square kilometres. Thus potential concentrations of carbon dioxide are extremely rare, but most cold traps can be found at the bottom of the relatively accessible Amundsen crater. The temperature there never exceeds -212 ° C, so it will be difficult to explore this area.