Our Place in Space: Shackleton Crater

Hello, friends!  Welcome to Our Place in Space: A to Z!  For this year’s A to Z Challenge, I’ll be taking you on a partly imaginative and highly optimistic tour of humanity’s future in outer space.  If you don’t know what the A to Z Challenge is, click here to learn more.  In today’s post, S is for…


You would not expect to find water on the Moon.  If there ever was water on the Moon, you’d expect it to boil away into the vacuum of space pretty quickly.  And yet there is growing scientific evidence suggesting that craters near the Moon’s north and south poles are full of frozen water.  In the distant future, the most important and famous of these water-filled craters will be Shackleton Crater.

Shackleton Crater is about 21 kilometers across and 4 kilometers deep.  For the sake of comparison, the Grand Canyon is just shy of 2 kilometers deep.  What’s really important, though, is that Shackleton Crater is located almost perfectly at the Moon’s south pole.  As a result, it doesn’t matter what time it is—it doesn’t matter what part of the lunar day/night cycle it it—the bottom of Shackleton Crater is always shielded from sunlight by those 4 kilometer tall crater walls.  Always.

That makes the bottom of Shackleton Crater extremely dark.  More importantly, it makes the bottom of the crater extremely cold—cold enough to overcome water’s natural tendency to boil (or sublimate) in a vacuum.

Shackleton Crater is not unique in that respect.  There are over three hundred craters around the Moon’s north and south poles that are in a state of perpetual darkness.  Any or all of these eternally dark craters could have frozen water inside them.  So what makes Shackleton Crater so extra special?  Well, once again, the crater is located almost perfectly at the Moon’s south pole.  As a result, while the bottom of the crater is always in darkness, sections of the crater rim are always in sunlight.

This combination of perpetual sunlight up here and perpetual darkness down there makes Shackleton Crater the #1 most valuable piece of real estate on the Moon.  If you built a moon base at Shackleton Crater, you could set up solar panels along the crater rim while also having easy access to all that frozen water at the bottom of the crater.

I don’t generally like making “in the next twenty years” predictions, but in the next twenty years, there’s a good chance that somebody will land at Shackleton Crater and build some sort of scientific research station.  Perhaps there will be several research stations, clustered together, almost village-like.

In time, that village on the Moon will grow.  And it will keep growing.  In the distant future, it would not surprise me if Shackleton Crater eventually became one of humanity’s first off-world metropolises.

Want to Learn More?

Check out these links: