If the political, tech, and budgetary stars join NASA and its partners in the coming years, the moon could be where the century unfolds. Astronauts would once again explore Earth’s celestial neighbor and perhaps initiate future mining efforts to extract ice likely lurking in sunlight-shy craters to be processed into water, oxygen and rocket propellant. People who “settle” on the moon could be a future perspective.
The next chapter in the US human exploration of the moon, the Artemis Project, will send crews there for extended periods of time, building on Apollo’s legacy. Between 1969 and late 1972, a dozen astronauts kicked up the powdery regolith, the dirt at the top of the moon. But there’s one flashback message from the Apollo moonwalkers worth paying attention to: the place is a Disneyland of fabric.
During their landings, dust blown up in the thin lunar atmosphere affected astronauts’ vision. Once the crews got to the moon, the dust had damaging effects on their spacesuits, helmets, equipment and instruments. Apollo expedition members could not escape tracking lunar material in their lunar landers. After removing their helmets and gloves, moonwalkers could feel the abrasive nature of the dust, even experience an “Apollo aroma” – a distinctive, fragrant scent.
As explained by the Apollo 17 crew on the Moon:
“I think dust is probably one of our biggest inhibitors for nominal operation on the moon. I think we can overcome physiological, physical or mechanical problems other than dust, ”said Mission Commander Eugene Cernan. “One of the most aggravating, limiting facets of lunar surface exploration is the dust and its adhesion to everything, regardless of the type of material, be it skin, suit, metal, whatever it is and the restrictive friction-like action. of it. on whatever it gets, ”said Harrison Schmitt, lunar module pilot and geologist.
AGENCY, INDUSTRY CARE
Study groups and technologists are investigating ways to reduce the negative impact of lunar dust on the astronauts, their equipment and surface activities.
Joel Levine, a research professor in applied science at The College of William and Mary in Williamsburg, Virginia, chaired and chaired a NASA workshop on lunar dust and its impact on human exploration. The message from that workshop in February was clear. “Before the first Artemis man lands on the moon, we need to better understand the particle size distribution, structure, chemical composition, potential toxicity, magnetic and electrical properties, and the dynamics and distribution of lunar dust,” he said.
The workshop’s findings were published Sept. 24 as a NASA Engineering and Safety Center Technical Assessment Report, stating that the dust problem “is an agency and industry problem affecting most mission subsystems and needs to be addressed.” The report also said it is critical that measurements and experiments are conducted and performed on the lunar surface by precursor landers to discover dust characteristics “that will affect hardware design and provide toxicological data to protect the health of the crew.”
PROTECT LUNAR GEAR
Future machines on the moon will face challenges, said Gerald Sanders, an in-situ resource utilization (ISRU) expert for NASA’s Space Technology Mission Directorate at Johnson Space Center in Houston. Unlike other equipment and instruments that work on the Moon, ISRU systems and hardware must operate continuously and in direct contact with lunar regolith and dust for very long periods of time. It is vital, he said, to develop techniques and technologies to resist wear, protect optical coatings and protect rotating mechanisms. Ultimately, easily replaceable components in lunar gear will be critical.
“While the Apollo missions and monsters that have returned to Earth have provided a wealth of information, we will not get a good idea of what the regolith looks like to design future ice-mining equipment until the VIPER rover enters a permanently shaded area. . Sanders said. NASA’s Volatiles Investigating Polar Exploration Rover, or VIPER, is a mobile robot that will go to the south pole of the moon, perhaps as early as December 2022 under NASA’s Commercial Lunar Payload Services program.
Philip Metzger, a planetary physicist in the University of Central Florida Faculty of Planetary Science, has focused his research on matter transport and its effects as a result of spacecraft landing on the moon.
“The exhaust from the Lunar Lander engine blows out dust, soil, gravel and rocks at high speed and will damage surrounding hardware, such as moon posts, mining operations or historic sites, unless the emissions are properly mitigated,” Metzger said.
Decades of research has provided a consistent picture of the physics of rocket exhaust blowing lunar soil, “but there are significant gaps,” Metzger added. “No modeling method currently available can fully predict the effects. However, the basic principles are understood well enough to start designing countermeasures. “
Metzger is Principal Investigator of the Ejecta Sheet Tracking, Opacity, and Regolith Maturity (STORM) instrument, set to fly on a Masten Space Systems Xodiac vertical takeoff and vertical landing system. The upcoming flight in Mojave, California, will measure the density and size of particles emerging during terrestrial simulations of moon landings.
INTEGRATED DUST CONTROL STRATEGY
NASA plans to place the first woman and the next man at the south pole of the moon by 2024. That location is being advocated as a future base camp, given possible access to ice and other mineral resources. However, the actual physical properties of the lunar dust and regolith in the polar regions are still unknown.
Jorge Núñez of the Planetary Exploration Group at Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, said a host of questions need to be addressed. “We can approximate and extrapolate based on the data we already have, but we won’t really know until we land in those regions,” he said.
“As we learned from the Apollo missions, lunar dust can cause a wide variety of problems, including a hazard to astronauts’ health, and adhere to all kinds of surfaces such as spacesuits, visors and windows, solar panels and radiators,” said Núñez . Moon dust also attacks seals, tissues and mechanisms. Dealing with dust requires an ‘integrated dust control strategy’, he added, such as using slow, methodical movements and allowing adequate time for dust cleaning protocols, and keeping space suits out of the pressurized habitat or the environment. lunar rover to use an electrodynamic dust screen to repel dust from materials.
Núñez said NASA’s Lunar Surface Innovation Initiative is accelerating the development of many of these dust-control technologies that are important for enabling human missions on the surface of the moon.
MOON SIMULANTS
The reactive nature of lunar dust to humans is another area highlighted by Karl Hibbitts of APL, lead facilitator for the Lunar Surface Innovation Consortium’s ISRU focus group. The lunar dust in this area has been known to be a nuisance since the Apollo era. The particles are very chemically reactive, he said, so the potential health risk (although several passivation techniques are being explored to make them less reactive).
“We’ve tried to study the reactivity of lunar soils in the lab,” said Hibbitts, “but the studies I know have all been done on samples already altered by Earth’s atmosphere. The new studies of carefully curated lunar soils will hopefully yield new insights. ”Furthermore, as for“ simulants ”- concoctions of earth-made material to imitate the properties of the lunar regolite – one has to choose which properties one needs to simulate the simulants. “It is not possible to create literally tons of lunar soil, or maybe even a small amount. Facilities are just now learning how to make realistic agglutinates, ”he added, and has yet to be reproduced: the nano-phase metallic iron present in the lunar regolith.
“We’re getting better at approximating the shape and size distribution function, but the reactivity can only be mimicked by production in a vacuum chamber and will always be limited to small quantities,” said Hibbitts SpaceNews.
So far, human contact with tiny, very sharp, glassy lunar dust particles took place only briefly during the Apollo missions, said Peter Sim, an emergency medicine specialist in Newport News, Virginia. But upon returning to the moon and establishing a long-lasting presence, lunar dust, in sufficient doses, poses a “toxic threat” to human health, he said.
The airways are particularly sensitive, Sim said, but the eyes, skin, and possibly the gastrointestinal tract and other organs can also be affected. Primary prevention of human exposure to lunar dust “should be our main goal,” he advised.
He added that NASA’s new Exploration Extravehicular Mobility Unit (xEMU) spacesuit will help keep the dust at bay. It has a group of dust resistant properties to prevent inhalation or contamination of the life support system of the suit. Still, keeping habitats dust-free by minimizing incursions and using effective atmospheric filtration systems will be a major challenge. “Monitoring the dust present in the lunar habitats will be crucial as it is where astronauts are most likely to be exposed. Therefore, the amount, size and potential toxicity of the ‘hab dust’ is of paramount importance, ”he said.
SpaceNews contributor Leonard David is the author of “Moon Rush: The New Space Race,” published by National Geographic in May 2019.
This article originally appeared in SpaceNews magazine December 14, 2020.