Studying Moon volcanoes to find breathable air and fuel for lunar bases
Volcanic eruptions are a breathtaking demonstration of the power and forces that lie beneath the surface of a planet. Volcanoes erupt molten magma from a planet’s interior, and can gush to produce lava flows or explode to create ash. Volcanic eruptions and deposits can tell us about the interiors of planets — how they formed, their structure, and their composition.
For example, volcanic glass is an important target for sampling on the Moon because it forms when magma quickly quenches, and can seal in gases from the interior that drove the eruption. Some of these gases include oxygen and water, which we potentially could extract for resources as part of future exploration on the Moon.
With this kind of data, we can guide missions to where the most useful resources are located to support future lunar habitats — like spots that might contain high abundances of oxygen, which could be used to generate fuel and breathable air for lunar bases. These sites are high-priority targets for samples to bring back for analysis in labs on Earth.
The Moon has a long history of volcanism — the dark patches on the planet that you can see with your naked eye are flood basalts that poured as fluid lavas between 1 billion and 4 billion years ago (most Apollo missions landed on these ancient lavas). The Moon has experienced very explosive volcanic eruptions, too, and this type of deposit is a big focus for human exploration.
My team is using satellite images and spectral data to understand the origins and properties of different types of explosive volcanic deposits on the Moon, many of which have been proposed as landing sites for human missions. We have used this visible/near-infrared spectral data to map minerals from orbit, and have developed new analysis tools to locate the Moon’s volcanic glass by studying the spectral properties of volcanic deposits on Earth.
My team is interested in understanding more about the gases in the interior of the Moon that drove the explosive eruptions, and why they varied in different locations and at different times. Why were some eruptions so explosive that they covered a huge fraction of the surface, while others only produced lava? Why did some erupt for a long time and build up into big volcanic edifices, while others did not? Answers to these questions will help us understand where the gases are in the Moon; the interior lunar structure; and, ultimately, how the Moon formed and evolved over time.
Our big finding so far has been that volcanic eruptions on the Moon were much more diverse than previously thought. Nearly every kind of volcanic eruption we know about on Earth has a lunar equivalent, which tells us the underlying geologic processes on the Moon also are pretty complicated. This discovery presents a challenge for sampling by astronauts — it means we can learn something new from almost every volcano we visit, but we might have to explore many sites to really piece together the history of water and other gases inside the Moon.
The next big step is to place these explosive eruptions within the story line of the evolution of the Moon. How did they change over time and space? How were they related to the big lava eruptions that formed the lunar mare (the dark patches we see on the near side, which were called “mare,” Latin for “sea,” by 17th century observers who thought they were oceans)? When did volcanism on the Moon begin, what did it look like, and what drove the earliest eruptions?
We can answer some of these questions by digging into satellite data, but others will require visiting the Moon and bringing samples back. One of our study sites, Schrödinger crater, recently was selected as a landing site for a NASA lander mission through the Commercial Lunar Payload Services (CLPS) program (lander missions involve a spacecraft descending slowly and landing softly on the surface of a planetary body). Another of our research sites, Marius Hills, is on the docket for the next round of NASA missions and may be visited by a Japanese mission in coming years. These forays will be incredibly helpful for interpreting our data, paving the way for crewed exploration.
Our funding for this work comes from NASA. We collaborate with scientists at NASA’s Goddard Space Flight Center and Johnson Space Center; the Lunar and Planetary Institute in Houston; and the United States Geological Survey (USGS) Astrogeology Center in Flagstaff, Arizona.
If everything at NASA goes according to plan, these volcanoes are going to be some of the most important sites that future landed robotic and crewed missions visit, because of both their scientific value and their possible resources. Studying these sites from orbit, on the ground, and as samples back in the lab will open up new understanding of the inner workings of moons and planets — allowing us to expand our presence on the Earth’s Moon to more locations in a more sustainable way.
Briony Horgan, PhD
Associate Professor, Department of Earth, Atmospheric, and Planetary Sciences
College of Science
Faculty Council member, Purdue Engineering Initiative in Cislunar Space
College of Engineering