Scientists have grown plants in lunar regolith for the first time.
This is cool.
It's nasty stuff. It's made of fine grains of rock that have broken down, eroded by micrometeorite impacts on the Moon, as well as cracking under thermal stress from the huge swing in temperature from day to night. The grains of regolith are jagged and sharp. It can get in machinery and cause damage, and if breathed in it mixes with mucus and causes coughing and sore throats.
It has uses. It makes sense to look into using whatever materials exist in situ, since it is very intensive to lift material from Earth to the Moon. NASA and the European Space Agency are looking into using regolith to make building materials.
Growing plants on the Moon is an area of study right now, especially with the lunar Artemis program starting to get going, because astronauts have this annoying desire to be able to breathe and eat.
Growing plants using regolith is worth investigating because it's everywhere on the Moon. The Apollo astronauts only brought a small amount of regolith back from the Moon, and the majority of it is rocks. NASA has not released samples for studies that will change the samples.
Scientists from the University of Florida Space Plants Lab convinced NASA to send them some samples after many attempts. The samples were less than half an ounce. It was enough to start testing.
The goal is not just to see if plants can be grown in regolith, but also to see what effects the weird stuff has on the plants and how that will affect future attempts to grow them on the Moon. One of the scientists performing the experiment said something that struck him: "what happens when you grow plants in lunar soil, something that is totally outside of a plant's evolutionary experience?" We didn't evolve for that environment, so what are the long-term effects?
They used seeds from a plant that biologists love. It's very common, and has had its genome mapped, making it great for testing, as the genetic code can be looked at before and after testing to see if there are changes.
They put the regolith in small wells in plastic. They were surprised that most of the plants grew.
It shows that the regolith doesn't interfere with the plant hormones that induce growth. They found that many of the cress plants were smaller and grew more slowly than the seeds that were planted in a control group.
I know that it's a sign of physical distress caused by environmental factors when my wife is a landscape designer and has a very green thumb. When the scientists looked at the plants' genome, they found markers that show stress caused by things like salts, metals, and oxidizing compounds.
It gives biologists a place to work to help the plants grow better. They found that they used samples of regolith from different Apollo missions, as well as material that was near the lunar surface and exposed long-term to space, and therefore Cosmic rays, tiny subatomic particles zipping through space at high speed. That helps in understanding why the plants didn't grow as well and may be important when astronauts on the Moon collect regolith for use.
There will be a day when that will happen. Establishing a permanent presence on the Moon will provide a lot of scientific knowledge. Even as rocket flights get cheaper and easier, there is still a lot to be gained by using materials from the Moon itself instead of hauling them up the gravity well, and the only way to find out is to stay there. Live there.
We have to understand as much as we can by studying the Moon here on Earth. Growing plants in the lunar regolith is an important step towards that future.
There is some evidence that plants were grown from regolith before, but it is not certain if it is true. My thanks to my friend, who pointed that out.
I don't like the term "lunar soil" because it's a term I don't like, and regolith is very different. I understand why the term is used, but I prefer to distinguish the two.