A team of scientists led by the University of Colorado at Boulder is proposing a new solution to the problem of dust on the moon – to remove the dirt with an electron beam. The study, published in the journal Acta Astronautica, presents the latest research on a persistent and perhaps surprising problem in humanity’s dreams of colonizing the dust moon. Astronauts walking or passing on the lunar surface raise huge amounts of lunar dust – regolith.
“This is really annoying,” said Xu Wang, a researcher at the Laboratory of Atmospheric and Space Physics (LASP) at CU Boulder. “Moon dust sticks to all surfaces – suits, solar panels, helmets – and can damage equipment”.
So he and his colleagues devised a possible solution – one that uses an electron beam, a device that releases a concentrated (and safe) stream of negatively charged particles with low energy. In a new study, the team aimed such a tool at a range of dirty surfaces inside the vacuum chamber. And they found that the dust just flew away.
Researchers still have a long way to go before real astronauts can use this technology for everyday cleaning. But according to the study’s lead author, Benjamin Farr, early findings from the study suggest that electron beam dust collectors could become an integral part of lunar bases in the not too distant future.
Some of the space pioneers have complained about moon dust, which often resists cleaning efforts. Harrison “Jack” Schmitt, who visited the moon with Apollo 17 in 1972, was allergic to the material and said it smelled like “waste gunpowder”.
Wang explained that the problem with moon dust is that it doesn’t look like the one that accumulates on bookshelves on Earth. Moon dust is constantly flooded with solar radiation, which gives the material an electrical charge. This charge, in turn, makes the dust even more sticky.
“Moon dust is very uneven and abrasive, like shards of glass”, Wang said.
Then the question arose before his group: how to separate this sticky substance from nature?
Electron beams have become a promising solution for scientists. According to a theory developed from recent scientific studies of how dust naturally rises to the surface of the moon, such a device could turn the electrical charges on the dust particles into a weapon against them. If you hit a layer of dust with a stream of electrons, Wang said, that dusty surface will collect additional negative charges. Insert enough charges into the gaps between the particles and they can start repelling each other – just like magnets do when the wrong ends are squeezed together.
“The charges get so big that they bounce off each other and then dust explodes from the surface”, Wang said.
To test this idea, he and his colleagues loaded various materials into a vacuum chamber, coated with a NASA-produced “simulated moon” resembling lunar dust.
Indeed, after aiming the electron beam at these particles, the dust scattered, usually in just a few minutes. This trick worked on a wide variety of surfaces, including spacesuit fabric and glass. According to scientists, this new technology is aimed at cleaning the smallest dust particles that are difficult to remove with brushes. The method was able to clean dusty surfaces by an average of 75-85%.
“It worked pretty well, but not good enough for us to finish”, Farr said.
Researchers are currently experimenting with new ways to increase the cleaning power of their electron beam.
But study co-author Mihai Horanyi, a professor at LASP and the CU Boulder Department of Physics, said the technology has real potential. NASA has experimented with other strategies for removing lunar dust, such as embedding a network of electrodes into spacesuits. However, an electron beam can be much cheaper and easier to deploy.
Horanyi imagines that one day the lunar astronauts can simply leave their spacesuits hung in a special room or even outside of their habitat and clean them up after a long day. The electrons will do the rest.
“To remove fine dust, you can simply enter the shower with an electron beam,” he concluded.