Category Archives: Moon

Moon, moon missions

Lunar Soil and Other Resources for Future Astronauts

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The Moon's soil could be a rich resource to help astronauts synthesize supplies they need for future missions. Courtesy LRO.
Lunar soil could be a rich resource to help astronauts synthesize supplies they need for future missions. Courtesy LRO.

When people begin long-term occupancy of the Moon, they’ll have to depend on local materials (lunar soil, etc.) for resources. It’s pretty expensive to transport everything from Earth to the Moon. So, any future colonies and science labs will need to become self-sufficient as soon as they can.

So, what resources will lunar citizens need? Water. Oxygen. Fuels. Materials for habitats. Some of that will be brought from Earth, at first. But, it’s gonna get expensive. So, other resources have to come into play.

We all know that there’s no running water on the Moon, and no air, and those are first-order priorities. Once lunar colonists establish their “beachheads”, they will have to synthesize what they need. That’s going to require quite a lot of infrastructure development beyond what gets brought in the first wave from Earth. At the moment, there are no manufacturing plants, labs, or even habitats on the Moon. Just robots and orbiters. That’ll change, of course.

Using Lunar Soil and Astronaut “Exhaust”

As it turns out, oxygen and water can be generated from lunar rocks and soil. And, of course, the lunar polar regions do harbor water ice. So, those resources are there, although they will take some work to unlock.

So, how do we get life-supporting substances from the Moon? First, look at all the resources available. Lunar soil is rich in materials that can convert carbon dioxide into oxygen and fuels, according to scientists at Nanjing University in China. They’re analyzing materials brought back to Earth from the Chang’e 5 mission. The sample seems to be abundant in iron and titanium. So, that’s one source of raw materials.

Another source is lunar astronauts themselves. As they work, they breathe out water vapor and carbon dioxide. That can be captured for use—it would be a shame to just let it escape, right?

The team at Nanjing analyzed those resources and proposed a strategy they called “extraterrestrial photosynthesis”. It would use water processed from lunar soil, plus that from the astronauts, and the elements in the soil itself. The process would then create such compounds as methane, which can be a fuel. Tweak the process another way, and you get oxygen and water. The beauty of this procedure is that it uses local materials. You don’t have to pay to bring stuff from Earth on a rocket.

The leader of the Nanjing team, Zhigang Zou, described the system they hope to develop for use on the Moon and h ow it would work. “We use in-situ environmental resources to minimize the rocket payload,” he said in a press statement. “Our strategy provides a scenario for a sustainable and affordable extraterrestrial living environment.”

Future Lunar Resources Synthesis Machines

The Nanjing team is testing different configurations of equipment to allow future lunar astronauts to create their fuels, oxygen, and water. In addition, they’re studying ways that the lunar soil can supply resources for materials useful in creating livable environments. If all goes well, future lunar inhabitants will become self-sufficient. According to Zao, that future isn’t all that far away.

“In the near future, we will see the crewed spaceflight industry developing rapidly,” he said. “But, if we want to carry out large-scale exploration…we will need to think of ways to reduce payload, meaning relying on as little supplies from Earth as possible and using extraterrestrial resources, instead.”

Zao described the team’s work in a peer-reviewed paper, “Extraterrestrial photosynthesis by Chang’E lunar soil”, published in the journal Joule, May 5, 2022.

astronomy, lunar reconnaissance orbiter, Moon

KREEP on the Moon

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Planetary scientists can usually tell a great deal about a world’s history by looking at its surface. This is particularly true of the Moon. Of course, we’re all familiar with the so-called “near side”—it’s what we see from here on Earth. It has large plains called “maria” (Latin for “oceans”). These are wide, dark-colored old lava flows that flooded the surface between 1 and 3 billion years ago. There are also many craters, which were “excavated” by objects plowing into the surface. In fact, the entire Moon is pockmarked with craters from that period.

The lunar Near side, as seen by NASA's Lunar Reconnaissance Orbiter in 2010. The large dark areas are the Mare, created by extensive volcanic flows. Impact craters surround the maria and imply a lot of bombardment early in the Moon's history. Courtesy NASA.
The lunar Near side, as seen by NASA’s Lunar Reconnaissance Orbiter in 2010. The large dark areas are called “maria”, created by extensive volcanic flows. Impact craters surround the mare and imply a lot of bombardment early in the Moon’s history. Courtesy NASA.

The lunar far side (the one that always faces away from us), looks much different. There are no maria, but we can see a LOT more craters over there. It’s almost like each side of the Moon has its own history. The Moon is tidally locked to Earth (meaning the far side always faces outward from Earth). So, we had no idea how different they were until the Space Age allowed orbiters to study the entire lunar surface.

The lunar Far side shows much more impact cratering and very few basins. The darkened area in the lower middle is the Aikin-South Pole basin. Image made by the Lunar Reconnaissance Orbiter between 2009-2011. Courtesy NASA.
The lunar Far side shows much more impact cratering and very few maria and basins. The darkened area in the lower middle is the Aikin-South Pole basin. Image made by the Lunar Reconnaissance Orbiter between 2009-2011. Courtesy NASA.

Explaining the Moon’s Two Sides

Most of the Moon’s craters formed during an event called the “Late Heavy Bombardment”. That happened some 3.8 billion years ago, although objects do still collide with the Moon today.

Still, there are some mysteries about the Moon that need solving. One of them involves a strange mix of chemical elements known as KREEP, and what their existence on the lunar near side tells us about its history.

Could KREEP be related to the difference between the two sides of the Moon? That’s a question that planetary scientists have been working to answer for many years. The visual evidence tells them that something happened. But, to get a true understanding of the event that caused the Moon to look so different, they looked for reasons that might explain the “two-sided dichotomy”.

A Heck of an Ancient Impact

Lately, scientists have pursued an idea that may tell the tale. It all starts with a feature near the lunar south pole called the “South Pole-Aitkin” (SPA) basin. It’s an impact basin that measures about 2500 kilometers across and over eight kilometers deep. It probably formed about four billion years ago. The most likely explanation is that a slow-moving object plowed into the Moon. The force of that impact melted a lot of rock and launched a plume of heat through the Moon.

An LRO image map of the Aitken-South Pole region on the Moon. Courtesy NASA.
An LRO image map of the Aitken-South Pole region. C ourtesy NASA.

As it traveled through the Moon, the plume would have carried such elements as thorium (which produces heat), rare earth metals, phosphorus, and other metals. That “splash” of heat would have spurred volcanic activity on the near side, creating the maria. In fact, there’s evidence for this idea in the chemical composition in a near side region called Oceanus Procellarum. It has a high concentration of these materials, often referred to as KREEP (K for potassium, REE is for rare earth elements, P is for potassium).

KREEP Tells the Tale

For a long time, scientists wondered how Procellarum could be rich with KREEP materials when the rest of the Moon isn’t. The impact that created the South Pole-Aitkin region would have been the trigger. In addition, the far side didn’t get “resurfaced” by volcanism since all the heat went to the near side. That could explain why the far side appears so much more cratered—its impacts weren’t obliterated by volcanic flows.

A computer model of heat convection in the Moon during and after an impact that sent a plume of heat and heat-producing elements through the lunar interior. Courtesy Brown University.
A computer model of heat convection in the Moon during and after an impact that sent a plume of heat and heat-producing elements through the lunar interior. Courtesy Brown University.

This hypothesis about the South Pole-Aitkin impact and its effect on the near side of the Moon is the latest attempt to tell the tale of the Moon’s two faces. It has been the subject of intense computer modeling by scientists at Brown University, Purdue, the Lunar and Planetary Science Laboratory, Stanford University, and NASA-JPL. You can read more about their work at this site.