Liquid metal spacesuits vs. lunar dust

In lieu of aliens or secret government bases, there is a very real and persistent threat on the Moon to future astronauts on NASA's Artemis mission – dust. This powdery substance is far from the commonplace kind we're used to earthside.

Lunar dust is the finest fraction of crushed regolith easily disturbed and distributed throughout the low-gravity atmosphere of the Moon. It differs significantly in its origin and properties from terrestrial soil. On Earth, particles are worn smooth by various types of erosion, differently affected and weighed down by stronger gravity, living processes, moisture and the like.

"There is no erosion on the Moon," said Erica Montbach, project manager for lunar dust mitigation at NASA's Glenn Research Center in Ohio. "That's one of the things that surprised me. When I first started, I thought, 'What's the big deal, we deal with dust on Earth a lot.' It's different because there is no erosion, so those individual particles end up being very sharp and angular. It is very damaging in ways that we don't see on Earth."

This sharp and superfine moon dust of lunar soil is made of statically active particles that cling to surfaces and grind between seams. It easily scours and corrodes, clogs ducts and coats surfaces causing overheating and can destroy the intricate moving parts of tools and spacesuits. All this poses a significant hazard to exposed equipment and astronaut health if inhaled.

Those dangers are compounded for longer exploration missions and threaten sustainability on the Moon, as well as future manned missions to Mars. In addition, lunar dust from the sun-facing side of the Moon is permanently exposed to solar radiation, creating a positive electrical charge, making it even clingier and harder to dislodge.

Reversing simple forces

Arif Rahman, an assistant professor of engineering at Hawaiʻi Pacific University, and his team could have the solution using liquid metal technology to repel lunar dust.

"During my research career, I have worked with liquid metals like gallium alloys, which have the unique capability to be turned on and off, allowing them to appear and disappear based on specific conditions. I am well-acquainted with these dynamic properties," said Rahman. "So, when I learned that NASA has a problem with lunar dust sticking to the surfaces and posing a significant threat to the equipment and to the astronauts, it occurred to me that liquid metals might offer a potential avenue for developing an electrostatic or electrodynamic shield to mitigate these issues with lunar dust."

To fund Rahman's research, NASA awarded HPU a $50,000 grant through the space agency's Minority University Research and Education Project (MUREP), which provides competitive awards to minority-serving institutions, including native Hawaiian-serving Institutions like HPU.

With this funding, Rahman and his team have developed Liquid Metal Electrostatic Protective Textile (LiqMEST), a fabric that will actively repel lunar dust while being flexible and stretchable.

The LiqMEST technology utilizes the same humble electrostatic forces that build up during lightning storms and zap from doorknobs after shuffling across carpet in socks.

"The technology is designed to be stretchable, and when activated, it generates an electric field that repels lunar dust, preventing the dust from adhering to the LiqMEST fabric. This strategy can be applied both to spacesuits and fabric covers for lunar equipment during moon missions," said Rahman.

An urgent need

NASA has been studying dust mitigation for decades, one of the main challenges for long-term astronaut habitats on the Moon.

With NASA planning to land astronauts on the surface of the moon once again with its Artemis program as early as 2025, time is ticking on coming up with final designs on spacesuits that can handle the dust and other rigors of living on the moon.

HPU's electrostatic tech isn't the only spacesuit solution under consideration. NASA has also space-tested a fabric variant on the exterior of the International Space Station through a project series called the Materials International Space Station Experiment (MISSE). The experiments test materials in harsh orbital conditions for months at a time, in a vacuum and with high radiation from the sun.

A team at NASA's Kennedy Space Center launched an electrodynamic dust shield to the International Space Station (ISS) as the first test in the series using the permanently installed test platform affixed to the exterior of the ISS. A follow-up mission, including the shield, called MISSE-15, launched in 2021, but results are not yet available on NASA's ISS experiment website.

Rahman and his team of HPU engineering students will work to produce a LiqMEST prototype by the end of May. Once completed, a full grant proposal will be submitted directly to NASA to begin developing functional products for upcoming space missions.