Human Lunar Missions Would Be Threatened By Dust Pileups: Study

Dust on the moon accumulates at a rate 10 times faster than previously believed, which could make it difficult for future human explorers to use solar power cells on the lunar surface, a new study says.

“You wouldn’t see it; it’s very thin indeed,” stated Brian O’Brien, a University of Western Australia professor who co-authored the research. “But, as the Apollo astronauts learned, you can have a devil of a time overcoming even a small amount of dust.”

O’Brien also developed the Lunar Dust Detector, an experiment that flew aboard three Apollo moon missions in the 1960s and 1970s. The experiment, which was about the size of a matchbox, had three tiny solar cells on board. Voltage from the experiment fell as dust accumulated.

His experiment was deployed on Apollo 12 (in 1969) and Apollos 14 and 15 (in 1971), then shut off in 1977 due to budget cutbacks.

In these years of data, electrical measurements showed that 100 microgams of lunar dust fell per year per square centimeter. “At that rate, a basketball court on the Moon would collect roughly 450 grams (1 pound) of lunar dust annually,” stated a press release from the American Geophysical Union.

Past models assumed that the dust built up because of meteor impacts and cosmic dust, but O’Brien’s data was far in excess of that. He suggested it could be because the moon has a “dust atmosphere” built up as individual particles jump between different locations.

“During each lunar day, solar radiation is strong enough to knock a few electrons out of atoms in dust particles, building up a slight positive charge,” the AGU stated.

“On the nighttime side of the Moon, electrons from the flow of energetic particles, called the solar wind, which comes off the sun strike dust particles and give them a small negative charge. Where the illuminated and dark regions of the moon meet, electric forces could levitate this charged dust, potentially lofting grains high into the lunar sky.”

Artist's conception of NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) orbiting above the moon. Credit: NASA Ames/Dana Berry
Artist’s conception of NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) orbiting above the moon. Credit: NASA Ames/Dana Berry

This data especially has resonance for NASA now that its Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft is orbiting about 155 miles (250 kilometers) above the moon. The agency is trying to learn more about how the dust environment on the moon works, particularly at the “terminator” — the point between light and darkness — where dust may levitate due to electrostatic charging.

“Something similar was reported by Apollo astronauts orbiting the Moon who looked out and saw dust glowing on the horizon,” stated Monique Hollick, who led the work and is also a researcher at the University of Western Australia.

The Surface Electrical Properties experiment deployed on the Apollo 17 mission. Scientists are concerned that solar panels, such as the one visible on this experiment, could quickly become unusable due to the buildup of lunar dust. Credit: NASA
The Surface Electrical Properties experiment deployed on the Apollo 17 mission. Scientists are concerned that solar panels, such as the one visible on this experiment, could quickly become unusable due to the buildup of lunar dust. Credit: NASA

NASA believed O’Brien’s data was lost for decades as the agency did not preserve the archival tapes, but in 2006 O’Brien — when he heard of NASA’s issue — informed them he still had the data.

“It’s been a long haul,” stated O’Brien. “I invented [the detector] in 1966, long before Monique was even born. At the age of 79, I’m working with a 23-year old working on 46-year-old data and we discovered something exciting—it’s delightful.”

The work was published this week in Space Weather and is available here.

Source: AGU

LADEE Lunar Probe Unveiled at NASA’s Wallops Launch Site in Virginia

NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) Observatory has arrived at the launch site on the Eastern Shore of Virginia at NASA’s Wallops Flight Facility on Wallops Island and is now in the midst of weeks of performance testing to ensure it is ready for liftoff in early September.

The LADEE lunar orbiting probe will be the first planetary science mission ever launched from NASA Wallops and the Mid-Atlantic Regional Spaceport (MARS). It will soar to space atop a solid fueled Minotaur V rocket on its maiden flight.

LADEE will blaze a brilliant trail to the Moon during a spectacular nighttime blastoff slated for Sept. 6, 2013 at 11:27 PM from Launch Pad 0B.

LADEE_1

LADEE is equipped with three science instruments to gather detailed information about the lunar atmosphere, conditions near the surface and environmental influences on lunar dust.

“LADEE will investigate the moons tenuous exosphere, trace outgases like the sodium halo and lofted dust at the terminator,” said Jim Green, Planetary Science Division Director at NASA HQ, in an exclusive interview with Universe Today.

“The spacecraft has a mass spectrometer to identify the gases, a physical dust detector and an imager to look at scattered light from the dust. These processes also occur at asteroids.”

“And it will also test a laser communications system that is a technology demonstrator for future planetary science missions. It communicates at 650 megabits per second,” Green explained to me.

The couch sized 844 pound (383 kg) robotic explorer was assembled at NASA’s Ames Research Center, Moffett Field Calif., and is a cooperative project with NASA Goddard Spaceflight Center in Maryland.

The LADEE spacecraft awaits spin balance testing, conducted to ensure stability during flight, at NASA’s Wallops Flight Facility in Virginia.  LADEE is slated to liftoff from Wallops  on Sep. 5, 2013  July 10.  Credit:  NASA/Patrick Black
The LADEE spacecraft awaits spin balance testing, conducted to ensure stability during flight, at NASA’s Wallops Flight Facility in Virginia. LADEE is slated to liftoff from Wallops on Sept. 6, 2013. Credit: NASA/Patrick Black

The spacecraft was then shipped cross country by a dedicated truck inside a specially-designed shipping container – blanketed with protective nitrogen – which insulated the spacecraft from temperature, moisture, bumps in the road and more than a few crazy drivers.

The first leg of LADEE’s trip to the Moon took 5 days. The trans lunar leg will take 30 days.

It’s standard practice that whenever space probes are moved by ground transportation that they are accompanied by a caravan that includes a lead scout vehicle to ensure safe road conditions and followed by engineers monitoring the health and environmental storage conditions.

Technicians are now engaged in a lengthy series of performance tests to confirm that LADEE was not damaged during the road trip and that all spacecraft systems are functioning properly.

“One important preparation about to begin is spin-balancing LADEE,” says Butler Hine, LADEE Project Manager. “During this procedure, the spacecraft is mounted to a spin table and rotated at a high-speed to make sure it is perfectly balanced for launch.”

After all spacecraft systems pass the performance tests, LADEE will be fueled, encapsulated and moved to the Wallops Island launch pad later this summer for mating with the five stage Minotaur V booster stack.

“I’m excited about the night launch because people up and down the Atlantic seacoast will be able to see it,” Green told me.

Ken Kremer

LADEE Launch Pad 0B at NASA Wallops Flight Facility in Virginia. Credit: Ken Kremer/kenkremer.com
Looking up the Flame Trench –
LADEE Launch Pad 0B at NASA Wallops Flight Facility in Virginia. Credit: Ken Kremer/kenkremer.com
Aerial view of NASA Wallops launch site on Virginia shore shows launch pads for both suborbital and orbital rockets. The Antares rocket Pad 0A for missions to the ISS is in the foreground.  Suborbital rockets blast off just behind the Pad 0A water tower. This photo was snapped from on top of Pad 0B that will soon launch NASA‘s LADEE orbiter to the Moon. Credit: Ken Kremer- kenkremer.com
Aerial view of NASA Wallops launch site on Virginia shore shows launch pads for both suborbital and orbital rockets. The Antares rocket Pad 0A for missions to the ISS is in the foreground. Suborbital rockets blast off just behind the Pad 0A water tower. This photo was snapped from on top of Pad 0B that will soon launch NASA‘s LADEE orbiter to the Moon. Credit: Ken Kremer- kenkremer.com

Moon Dust Could ‘Engulf’ Lunar Rovers — Especially During Sunrise and Sunset

Apollo 17 Mission

That video above is perhaps the ultimate off-roading adventure: taking a rover out for a spin on the moon. Look past the cool factor for a minute, though, and observe the dust falling down around that astronaut.

The crew aboard Apollo 16 (as well as other Apollo missions) had a lot of problems with regolith. It got into everything. It was so abrasive that it wore away some equipment in days. It smelled funny and probably wasn’t all that good to breathe in, either. Many have said that when we return to the moon, dust must be dealt with for long-term survival.

Things could get worse at sunrise and sunset. One new study (not peer-reviewed yet) finds a “serious risk” that rovers “could be engulfed in dust.” That’s because lunar dust appears to have electrostatic properties that, somehow, is triggered by changes in sunlight. (NASA is already doing some serious investigation into this matter using its orbiting missions.)

What the researchers did, in conjunction with ONERA (The French Center of Aerospace Research) was conduct simulations for two types of lunar regions — the terminator (the day/night boundary) and an area experiencing full sunlight.

“Dust particles were introduced into the simulation over a period of time, when both the surface and the rover were in electrical equilibrium,” the Royal Astronomical Society stated.

“In both the test cases, dust particles travel upwards above the height of the rover, but results suggest that they move in different directions. On the day side, the particles are pushed outwards and on the terminator the dust travels upwards and inwards above the rover, regrouping in the vacuum above it. The terminator simulation began with a region void of dust which was later filled by lunar dust particles.”

The bottom line? A lunar rover could accumulate a significant amount of dust on the moon, especially if it’s sitting at or near the terminator. This could be addressed by using dome-shaped rovers that would see the dust fall off, added lead author Farideh Honary, a physicist at the University of Lancaster, in a statement.

The work was presented at the RAS National Astronomy Meeting today (July 3). A paper has been submitted to the Journal for Geophysical Research, so more details should be forthcoming if and when it is published.

Credit: Royal Astronomical Society

The Moon Is Toxic

As our closest neighbor in space, a time-capsule of planetary evolution and the only world outside of Earth that humans have stepped foot on, the Moon is an obvious and ever-present location for future exploration by humans. The research that can be done on the Moon — as well as from it — will be invaluable to science. But the only times humans have visited the Moon were during quick, dusty  jaunts on its surface, lasting only 2-3 days each before departing. Long-term human exposure to the lunar environment has never been studied in depth, and it’s quite possible that — in addition to the many inherent dangers of living and working in space — the Moon itself may be toxic to humans.

An international team of researchers has attempted to quantify the health dangers of the Moon — or at least its dust-filled regolith. In a paper titled “Toxicity of Lunar Dust” (D. Linnarsson et al.) the health hazards of the Moon’s fine, powdery dust — which plagued Apollo astronauts both in and out of their suits — are investigated in detail (or as best as they can be without actually being on the Moon with the ability to collect pristine samples.)

Within their research the team, which included physiologists, pharmacologists, radiologists and toxicologists from 5 countries, investigated some of the following potential health hazards of lunar dust:

Inhalation. By far the most harmful effects of lunar dust would come from inhalation of the particulates. Even though lunar explorers would be wearing protective gear, suit-bound dust can easily make its way back into living and working areas — as Apollo astronauts quickly discovered. Once inside the lungs the super-fine, sharp-edged lunar dust could cause a slew of health issues, affecting the respiratory and cardiovascular system and causing anything from airway inflammation to increased risks of various cancers. Like pollutants encountered on Earth, such as asbestos and volcanic ash, lunar dust particles are small enough to penetrate deep within lung tissues, and may be made even more dangerous by their long-term exposure to proton and UV radiation. In addition, the research suggests a microgravity environment may only serve to ease the transportation of dust particles throughout the lungs.

Skin Damage. Lunar regolith has been found to be very sharp-edged, mainly because it hasn’t undergone the same kind of erosive processes that soil on Earth has. Lunar soil particles are sometimes even coated in a glassy shell, the result of rock vaporization by meteorite impacts. Even the finer particles of dust — which constitute about 20% of returned lunar soil samples — are rather sharp, and as such pose a risk of skin irritation in instances of exposure. Of particular note by the research team is abrasive damage to the outer layer of skin at sites of “anatomical prominence”, i.e., fingers, knuckles, elbows, knees, etc.

“The dust was so abrasive that it actually wore through three layers of Kevlar-like material on Jack [Schmitt’s] boot.”

– Professor Larry Taylor, Director of the Planetary Geosciences Institute, University of Tennessee (2008)

Eye Damage. Needless to say, if particles can pose abrasive damage to human skin, similar danger to the eyes is also a concern. Whether lunar dust makes its way into the eye via airborne movement (again, much more of a concern in microgravity) or through direct contact from fingers or another dust-coated object, the result is the same: danger of abrasion. Having a scratched cornea is no fun, but if you’re busy working on the Moon at the time it could turn into a real emergency.

While the research behind the paper used data about airborne pollutants known to exist on Earth and simulated lunar dust particles, actual lunar dust is harder to test. The samples returned by the Apollo missions have not been kept in a true lunar-like environment — being removed from exposure to radiation and not stored in a vacuum, for instance — and as such may not accurately exhibit the properties of actual dust as it would be encountered on the Moon. The researchers conclude that only studies conducted on-site will fill the gaps in our knowledge of lunar dust toxicity. Still, the research is a step in the right direction as it looks to ensure a safe environment for future explorers on the Moon, our familiar — yet still alien — satellite world.

Read the team’s paper in full here.

“The Apollo astronauts reported undesirable effects affecting the skin, eyes and airways that could be related to exposure to the dust that had adhered to their space suits during their extravehicular activities and was subsequently brought into their spacecraft.”

– Dag Linnarsson, lead author, Toxicity of Lunar Dust

Top image: Apollo 16 astronaut Charlie Duke with a dust-coated LRV. Side image: a dusty Gene Cernan in the LM at the end of an Apollo 17 EVA. (NASA/JSC)