NASA’s Artemis return humans to the Moon by 2024 program.
Credit: NASA

Between 1969 and the end of 1972, twelve U.S. astronauts kicked up the powdery regolith, the topside dirt of the Moon. They were later dubbed the “dusty dozen.” Along with invaluable lunar samples, Apollo moonwalkers brought back a significant message to Earth: The Moon is a Disneyland of dust.

A vial of Apollo 11 Moon dust from a lunar sample collected in 1969.
Credit: Marilee Bailey/Lawrence Berkeley National Laboratory

Those 20th century human outings confronted the harmful impact of lunar dust on the astronauts and their equipment, including their spacesuits. Lunar dust is an abrasive powder that clings to space suits, robots, and virtually all machinery.

Dust up on the Moon. Apollo 17 commander Eugene Cernan prepares to doff lunar dust-covered space suit.
Credit: NASA

Apollo expedition members tracked lunar material inside their Moon lander homes. After doffing their helmets and gloves, moonwalkers could feel the abrasive nature of the dust, as well as smell and even taste the Moon. Since the dust became weightless after departure from the Moon, the astronauts had trouble breathing without their helmets.

Go-to place

Now, fast forward to the 21st century.

Apollo 17 helmets and dusty spacesuits stuffed inside lunar lander following the last human treks on the Moon in December 1972.
Credit: NASA

Earth’s Moon is slated to be the “go-to” place as the century progresses, with crews exploring, mining and “settling in” on lunar territory, extracting ices likely hidden in Sun-shy polar craters for transformation into water, oxygen, and rocket fuel.

Artist impression of activities in a Moon Base.
Power generation from solar cells, food production in greenhouses and construction using mobile 3D printer-rovers.
Credit: ESA – P. Carril

All that said, there’s need to deal with the impact of lunar dust on astronauts and their surface system equipment.

Research scientists are gathering this week at the Lunar and Planetary Institute in Houston, Texas to appraise the impact of dust on future human exploration of the Moon. That includes health effects of Moon dust.

Unexpected discovery

“The Apollo Missions to the Moon led to the unexpected discovery that lunar dust has a very negative impact on the astronauts, their surface systems, including space suits and helmets, other surface equipment and on lunar surface operations,” explains Joel Levine of the College of William and Mary and NASA Engineering and Safety Center. He is convener of this week’s “Impact of Lunar Dust on Human Exploration Workshop.”

Credit: NASA

The next phase of the U.S. human exploration of the Moon, the Artemis Project, will send humans back to the Moon for longer periods that the astronauts will be on the lunar surface and exposed to lunar dust, Levine adds. “It is critical to the success of future human lunar missions that we develop techniques and technologies to reduce and mitigate the negative impact of lunar dust on the astronauts, their surface systems and surface operations.”

 

Astronaut John Young works at the mission’s Apollo 16 Moon buggie in April 1972.
Credit: NASA

Different century, same problems?

The challenges of lunar dust were well documented by the Apollo program. Engine blast ejecta, seal contamination, spacesuit zipper problems, as well as degradation of optical surfaces among them, reports NASA engineer, John Connolly.

“The physics of lunar crewed missions has not changed since Apollo, and the technologies, materials and systems have changed only incrementally,” Connolly notes. So the question persists: will lunar dust present the same challenges to 21st century lunar explorers as it did to 20th century explorers?

“The 50 years that have passed have given us a greater understanding of lunar regolith chemistry, physical properties and its interaction with exploration systems,” Connolly points out. “New understanding, however, often poses new questions,” he suggests.

Wanted: dust mitigation strategy

NASA’s M. R. Johansen explains it is well known that the Apollo lunar surface missions experienced a number of issues related to dust – which are sometimes referred to as “The Dust Problem.”

Moonwalking geologist, Apollo 17’s Jack Schmitt.
Credit: NASA

“The jagged, electrostatically charged lunar dust particles can foul mechanisms and alter thermal properties. They tend to abrade textiles and scratch surfaces. NASA and other interested parties require an integrated, end-to-end dust mitigation strategy to enable sustainable lunar architectures,” Johansen says.

An integrated dust mitigation strategy requires coordination from architecture to technology development, Johansen points out. “Many of the concerns associated with lunar dust can be lessened with early consideration. Through architecture and operational considerations and technology maturation, NASA aims to resolve The Dust Problem.”

Blast effects

Philip Metzger, a planetary physicist with the Planetary Science faculty at the University of Central Florida, has focused research on dust transport and its effects due to landing spacecraft on the Moon.

Apollo 12’s visit to Surveyor III landing site.
Credit: NASA

“Lunar lander engine exhaust blows dust, soil, gravel, and rocks at high velocity and will damage surrounding hardware such as lunar outposts, mining operations, or historic sites unless the ejecta are properly mitigated,” says Metzger.  

Metzger explains that the best information about damage from impact of these ejecta comes from the robotic Surveyor 3 lunar lander visited by Apollo 12 moonwalkers two and a half years after the probe plopped down on the Moon.

Pieces of the Surveyor were cut off by the Apollo astronauts and brought back to Earth. The Surveyor’s surface facing the Apollo lunar module had been sandblasted thoroughly. On Surveyor, they crushed the paint pigment and mixed dust into the paint, Metzger reports.

Twenty years of research have developed a consistent picture of the physics of rocket exhaust blowing lunar soil, “but significant gaps exist,” Metzger  adds. “No currently-available modeling method can fully predict the effects. However, the basics are understood well enough to begin designing countermeasures.”

Health consequences

Flagged by Peter Sim, an emergency medicine specialist in Newport News, Virginia, are the health consequences of human exposure to lunar dust.

Flow chart shows the possible health effects of breathing lunar dust, in both the short- and long-term.
Credit: Rachel Caston

Human contact with lunar dust has only occurred briefly, during the Apollo missions, Sim explains in his abstract for the meeting this week.

Apollo 17 lunar module pilot Harrison Schmitt’s exposure resulted in symptoms he described as “lunar hay fever,” Sim notes. “In the 47 years since Apollo 17, returned samples of lunar regolith and dust have been exhaustively analyzed, but there are still important gaps in our knowledge.”

The respiratory system is most at-risk, Sim says, but the eyes and skin will also be affected. “Obviously, prevention of exposure should be the primary objective, but plans to minimize and mitigate inevitable exposures must be in place. Keeping habitats dust-free will be a major challenge.”

Credit: NASA/ESA

 

The paper offered by Sim concludes: “Because of its physical and chemical characteristics, lunar dust, in sufficient doses, represents a toxic threat to human health when we return to the Moon and establish a long-term presence. The respiratory system is particularly at risk. Prevention of exposure should be our primary goal.”

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