- Researchers use Atom Probe Tomography to analyze lunar soil.
- The technique uses only a single grain of soil to identify helium, pure iron, water, and products of space weathering.
- This is the first time a sample extracted from the Moon has been analyzed like this.
The samples collected from the Moon in Apollo missions are a precious thing. Since we have not launched any manned mission to the Moon in almost 5 decades, every piece of the sample counts for scientists now and in the future.
Keeping this in mind, researchers at the Field Museum and the University of Chicago have discovered a new way to examine lunar samples using just one grain of dust.
The new technique can help scientists understand more about the formation of resources (like helium and water) and conditions on the surface of the Moon. According to the researchers, this is the first time a sample extracted from the Moon (in 1972) has been analyzed like this.
Atom Probe Tomography
The method used in this study is known as Atom Probe Tomography (APT). It is a material analysis technique used to visualize and quantify the microstructure of materials at the atomic scale. It is mostly used to enhance industrial procedures such as making nanowires and steel.
APT’s extensive capabilities make it a perfect candidate for analyzing lunar samples. Since Apollo 17 brought 111 kilograms of lunar soil and rocks back to Earth, scientists have to use it wisely.
While most of the analysis techniques use samples in milligrams or micrograms, APT requires only a single grain of soil to identify helium, pure iron, water, and products of space weathering formed by the interactions of the space environment and lunar soil.
Regolith collected during Apollo 17 mission | Credit: National Museum of Natural History
How Exactly Does It Work?
Using a focused beam of charged atoms, researchers were able to carve out a small grain of moondust, just a few hundred atoms thick. To put this into perspective, a paper sheet is hundreds of thousands of atoms wide.
They then used a laser to knock off atoms (from the grain of moondust) at the detector plate. Different atoms took different time to reach the detector. For example, lighter elements (such as hydrogen) take less time to reach the detector plate than heavier elements (such as iron).
The device measured how much time the atom took to reach the detector, and determined the type of atom (as well as its charge) at that spot. For better visualization, the research team constructed a 3D map of the moondust, using a color-coded point for each atom and molecule.
The same technique can be applied to samples collected from asteroids. This will give astronauts insights into an important phenomenon called space weathering and accurately predict the composition of moons and asteroids.
And since researchers used just a tiny tip, the original grain of the moondust is still available for further analysis. Hundreds of such grains could be extracted from an astronaut’s glove, which would be enough for future studies.
The findings convinced NASA to fund the research team for the next 3 years. They will use the same method to analyze various types of lunar dust and investigate different aspects of space weathering.