Air From Moonrocks

A focusing lens to produce oxygen and slug from a vacuum moondust filled chamber. Image credit: NASA. Click to enlarge
When astronauts return to the Moon, to explore and eventually build a moon base, they’re going to need oxygen… and lots of it. Fortunately lunar soil – or regolith – is almost half oxygen. NASA researchers are using a technique called vacuum pyrolysis, where the regolith is heated until it releases oxygen. Light from the Sun was focused by a lens to heat lunar soil to 2,500 degrees C. As much as 20% of the soil was converted to free oxygen, and the leftover slag could be used for bricks, radiation shielding or pavement.

An early, persistent problem noted by Apollo astronauts on the Moon was dust. It got everywhere, including into their lungs. Oddly enough, that may be where future Moon explorers get their next breath of air: The moon’s dusty layer of soil is nearly half oxygen.

The trick is extracting it.

“All you have to do is vaporize the stuff,” says Eric Cardiff of NASA’s Goddard Space Flight Center. He leads one of several teams developing ways to provide astronauts oxygen they’ll need on the Moon and Mars. (See the Vision for Space Exploration.)

Lunar soil is rich in oxides. The most common is silicon dioxide (SiO2), “like beach sand,” says Cardiff. Also plentiful are oxides of calcium (CaO), iron (FeO) and magnesium (MgO). Add up all the O’s: 43% of the mass of lunar soil is oxygen.

Cardiff is working on a technique that heats lunar soils until they release oxygen. “It’s a simple aspect of chemistry,” he explains. “Any material crumbles into atoms if made hot enough.” The technique is called vacuum pyrolysis–pyro means “fire”, lysis means “to separate.”

“A number of factors make pyrolysis more attractive than other techniques,” Cardiff explains. “It requires no raw materials to be brought from Earth, and you don’t have to prospect for a particular mineral.” Simply scoop up what’s on the ground and apply the heat.

In a proof of principle, Cardiff and his team used a lens to focus sunlight into a tiny vacuum chamber and heated 10 grams of simulated lunar soil to about 2,500 degrees C. Test samples included ilmenite and Minnesota Lunar Simulant, or MLS-1a. Ilmenite is an iron/titanium ore that Earth and the Moon have in common. MLS-1a is made from billion-year-old basalt found on the north shore of Lake Superior and mixed with glass particles that simulate the composition of the lunar soil. Actual lunar soil is too highly prized for such research now.

In their tests, “as much as 20 percent of the simulated soil was converted to free oxygen,” Cardiff estimates.

What’s leftover is “slag,” a low-oxygen, highly metallic, often glassy material. Cardiff is working with colleagues at NASA’s Langley Research Center to figure out how to shape slag into useful products like radiation shielding, bricks, spare parts, or even pavement.

The next step: increase efficiency. “In May, we’re going to run tests at lower temperatures, with harder vacuums.” In a hard vacuum, he explains, oxygen can be extracted with less power. Cardiff’s first test was at 1/1,000 Torr. That is 760,000 times thinner than sea level pressure on Earth (760 Torr). At 1 millionth of a Torr — another thousand times thinner — “the temperatures required are significantly reduced.”

Cardiff is not alone in this quest. A team led by Mark Berggren of Pioneer Astronautics in Lakewood, CO, is working on a system that harvests oxygen by exposing lunar soil to carbon monoxide. In one demonstration they extracted 15 kg of oxygen from 100 kg of lunar simulant–an efficiency comparable to Cardiff’s pyrolysis technique: more.

D.L. Grimmett of Pratt & Whitney Rocketdyne in Canoga Park, CA, is working on magma electrolysis. He melts MLS-1 at about 1,400 deg. C, so it is like magma from a volcano, and uses an electric current to free the oxygen: more.

Finally, NASA and the Florida Space Research Institute, through NASA’s Centennial Challenge, are sponsoring MoonROx, the Moon Regolith Oxygen competition. A $250,000 prize goes to the team that can extract 5 kg of breathable oxygen from JSC-1 lunar simulant in just 8 hours.

The competition closes June 1, 2008, but the challenge of living on other planets will last for generations.

Got any hot ideas?

Original Source: NASA News Release

Crater Hopmann by SMART-1

ESA’s SMART-1 spacecraft captured this photograph of Crater Hopmann, located on the Moon. Only a quarter of the full crater is visible in this photograph, and it contains several other smaller craters inside of it. The small crater chains are created when secondary debris is blasted off the surface of the Moon, and then falls back in an arc of molten droplets. This area isn’t visible from the Earth because it’s on the far side of the Moon – only spacecraft have ever seen it.

This image, taken by the advanced Moon Imaging Experiment (AMIE) on board ESA’s SMART-1 spacecraft, shows one quarter of crater Hopmann – an impact structure about 88 kilometres in diameter.

AMIE obtained this image on 25 January 2006 from a distance of about 840 kilometres from the surface, with a ground resolution of 76 metres per pixel.

The imaged area, not visible from Earth because it is located on the far side of the Moon, is positioned at latitude of 51.7 degrees South and longitude 159.2 degrees East. It covers a square of about 39 kilometres per side.

The crater (centred at 50.8 degrees South, 160.3 degrees East) is situated on the edge of the giant South Pole-Aitken basin SPA, the largest impact crater in the solar system with a diameter of 2500 kilometres and a depth of 13 kilometres. The SPA basin shows distinctive chemical composition with unusual mineralogy types, and possible exposure of rocks from the lower crust or the upper mantle.

The hills on the lower left side are the crater wall of Hopmann. This crater is very old – many small craters can be seen on its flat floor, the largest one showing an interesting double-ringed structure. The outer rim has been also eroded by later impacts.

The small crater chains to the left of Hopmann can be interpreted as series of so-called ‘secondary craters’, created by the impact of the material ejected from a nearby large impact. This ejected material flies away in molten state, and fall in large ‘droplets’. When these impact on the surface, they form typical crater chains as those visible in this image.

The crater is named after Josef Hopmann (1890-1975), an astronomer that worked in Bonn, Leipzig and as Director of the Vienna Observatory.

Original Source: ESA Portal

New Spacecraft Will Search for Lunar Ice

An artist’s conception of LRO on its way to the moon. Image credit: NASA Click to enlarge
NASA announced a new spacecraft today that will search for ice at the Moon’s southern pole: the Lunar CRater Observation and Sensing Satellite (LCROSS). The spacecraft will launch as a secondary payload with the Lunar Reconnaissance Orbiter in 2008. As it approaches the Moon, LCROSS will split into two spacecraft. The first will smash into the Moon’s south pole, and the second will fly through the resulting plume, analyzing it for traces of water. This mission will be developed on a shoestring; NASA has allocated a total of $80 million for its development.

NASA today announced that a small, ‘secondary payload’ spacecraft, to be developed by a team at NASA Ames Research Center, Moffett Field, Calif., has been selected to travel to the moon to look for precious water ice at the lunar south pole in October 2008.

The smaller secondary payload spacecraft will travel with the Lunar Reconnaissance Orbiter (LRO) satellite to the moon on the same rocket, the Evolved Expendable Launch Vehicle (EELV), to be launched from Kennedy Space Center, Florida. The NASA Ames team proposed the secondary payload mission, which will be carried out by the Lunar CRater Observation and Sensing Satellite (LCROSS).

“The LCROSS mission gives the agency an excellent opportunity to answer the question about water ice on the moon,” said Daniel Andrews of NASA Ames, whose team proposed the LCROSS mission. “We think we have assembled a very creative, highly innovative mission, turning the upper stage of the rocket that brought us to the moon into a substantial impactor on the moon.”

After launch, the secondary payload LCROSS spacecraft will arrive in the lunar vicinity independent of the LRO satellite. On the way to the moon, the LCROSS spacecraft’s two main parts, the Shepherding Spacecraft (S-S/C) and the Earth Departure Upper Stage (EDUS), will remain coupled.

As the spacecraft approaches the moon’s south pole, the upper stage will separate, and then will impact a crater in the south pole area. A plume from the upper stage crash will develop as the Shepherding Spacecraft heads in toward the moon. The Shepherding Spacecraft will fly through the plume, and instruments on the spacecraft will analyze the cloud to look for signs of water and other compounds. Additional space and Earth-based instruments also will study the 2.2-million-pound (1000-metric-ton) plume.

“The LCROSS mission will help us determine if there is water hidden in the permanently dark craters of the moon’s south pole,” said Marvin (Chris) Christensen, Robotic Lunar Exploration Program (RLEP) manager, and acting director of NASA Ames. “If we find substantial amounts of water ice there, it could be used by astronauts who later visit the moon to make rocket fuel,” Christensen added.

Earlier, NASA had requested proposals internally from its NASA field centers for existing or reasonably matured concepts for secondary payloads that would offer cost-effective contributions to RLEP.

To prepare for the return of astronauts to the moon, NASA will conduct various RLEP robotic missions from 2008 to potentially 2016 to study, to map and to learn about the lunar surface. These early missions will help determine lunar landing sites and whether resources, such as oxygen, hydrogen and metals, are available for use in NASA’s long-term lunar exploration objectives.

“Establishing research stations on the moon will give us the experience and capabilities to extend to Mars and beyond,” noted robotics deputy program manager Butler Hine of Ames.

“An exploration science program with a sustained human presence on the moon gives us the opportunity to conduct fundamental science in lunar geology, history of the solar system, physics and the biological response to partial (Earth) gravity,” said Christopher McKay, lunar exploration program scientist at Ames.

The space agency specified that the winning proposal must demonstrate an affordable concept beneficial to RLEP, according to the document that asked NASA centers to submit suggestions for the secondary payload. NASA noted that the secondary payload mission should cost no more than $80 million. NASA also required that the payload mass not exceed 2,205 pounds (1,000 kilograms).

NASA encouraged its field centers to team with industry to develop proposals. On Jan. 10, NASA issued a request for information to industry to allow businesses to provide secondary payload concepts to NASA. Each NASA center reviewed ideas from industry as well as secondary payload concepts developed internally.

NASA asked that the concepts advance the Vision for Space Exploration to include missions that evolve lunar science, characterize the lunar environment and support identification sites for future human missions as well as the utility of those sites.

The space agency said that it was looking for missions that demonstrate technology that could enhance future exploration, that show operational schemes to support exploration, that develop or emplace infrastructure in support of exploration, that advance commercial opportunities and those missions that would collect engineering data to support the Constellation program. That program is developing NASA’s new spaceship, the Crew Exploration Vehicle.

For images related to the LCROSS mission, please visit:
http://www.nasa.gov/centers/ames/multimedia/images/2006/lunarorbiter.html

For additional high-resolution images of the and historic information, please visit:
http://www.nasa.gov/centers/ames/news/releases/2004/moon/moon.html

http://lunar.arc.nasa.gov/

http://nssdc.gsfc.nasa.gov/planetary/lunarprosp.html

http://science.nasa.gov/newhome/headlines/ast31jul99_1.htm

Original Source: NASA News Release

Swirling Feature on the Moon

Reiner Gamma Formation. Image credit: ESA/Space-X. Click to enlarge
This image was taken by ESA’s SMART-1 spacecraft, and shows a bright feature on the surface of the Moon called the Reiner Gamma Formation. This is a bright spot on the Moon which is totally flat, and surrounded by much darker “mare”. Ground observations originally misidentified it as a crater, but when US and Russian spacecraft visited the Moon, they revealed this strange swirling morphology.

These images taken by the Advanced Moon Imaging Experiment (AMIE) on board ESA’s SMART-1 spacecraft, shows a feature characterised by bright albedo, and called Reiner Gamma Formation.

The Reiner Gamma Formation, a totally flat area consisting of much brighter material than the surrounding dark ‘mare’, is centred on an area located at 57.8 degrees West, 8.1 degrees North, in the Oceanus Procellarum on the near (visible) side of the Moon, and has an extension of approximately 30 by 60 kilometres.

The AMIE camera obtained the images on 14 January 2006, from a distance between 1599 and 1688 kilometres and with a ground resolution between 144 and 153 metres per pixel.

From early ground-based observations, this feature was initially misidentified as a crater. Only later detailed observations from orbit (such as those performed by USSR’s Zond-6, and NASA’s Lunar Orbiter, Apollo and Clementine missions) revealed its true nature: a very unusual morphology, consisting of swirl-like patterns that do not correspond to any topographic features.

Its main part consists of a bright pattern of elliptical shape, located to the west of Reiner crater. Bright elongated patches extend to the northeast in the Marius Hills region and small swirls extend to the southwest. The origin of the Reiner Gamma Formation and other swirls occurring on the lunar surface is still unclear.

Lunar swirls are associated with magnetic anomalies and some of these swirls – such as Mare Ingenii and Mare Marginis – are ‘antipodal’ to large impact structures (that is they are located right into opposite regions of the Moon globe).

So, it was suggested that the Reiner Gamma swirls correspond to magnetised materials in the crust or iron-rich ejecta materials able to deflect the solar wind (constant flow of charged particles coming from the Sun). This would prevent surface materials to undergo maturation processes, and so produce an optical anomaly.

However, Reiner Gamma Formation still stands as a particular case. In fact, the magnetic anomaly does not correlate with the scale of the lunar crust structure and large-scale anomalies seen on the far side. Furthermore, the anomaly is not associated with any obvious antipodal basin structure, and the surface material related to Reiner Gamma appears optically very immature (the age for its emplacement could be quite recent).

The analysis of NASA’s Clementine imaging data showed that the optical and spectroscopic properties of the local regolithic surface layer are close to those of immature mare crater-like soils. This is consistent with the properties of a shallow subsurface mare soil layer.

Considerations from works on impact cratering support the hypothesis that the uppermost part of the regolith could have been modified through an interaction with falling fragments of a low-density comet nucleus, previously broken by tidal forces and having ploughed the regolith.

Then, the magnetic anomaly would not be the result of an antipodal crustal field generated in the formation process of large impact basins. It would rather arise from local effects during the interaction between the lunar surface and cometary physical environment, with the possibility that the solar wind is locally deflected and contributes to the unusual optical properties.

So, the Reiner Gamma Formation could be an interesting site for future human exploration because of the radiation deflected from the surface. Further testing of this hypothesis requires access to the physical properties of the surface to constrain the mechanisms of formation of the lunar swirls. This is an ongoing task for the AMIE camera, aimed at studying regolith photometric properties.

Original Source: ESA Portal

Watch Out for Moonquakes

Buzz Aldrin deploys a seismometer at the moon surface. Image credit: NASA Click to enlarge
During the Apollo Moon missions – between 1969 and 1972 – NASA astronauts placed seismometers at their landing sites to detect if the Moon has earthquakes (moonquakes). The equipment mostly detected minor tremors, but it also experienced some fairly strong ones, measuring greater than 5.5 on the Richter scale. And they lasted for a very long time, sometimes going on for 10 minutes. If the next group of astronauts will be visiting the Moon for any length of time, they’ll need a lunar base that can withstand the occasional trembler.

NASA astronauts are going back to the moon and when they get there they may need quake-proof housing.

That’s the surprising conclusion of Clive R. Neal, associate professor of civil engineering and geological sciences at the University of Notre Dame after he and a team of 15 other planetary scientists reexamined Apollo data from the 1970s. “The moon is seismically active,” he told a gathering of scientists at NASA’s Lunar Exploration Analysis Group (LEAG) meeting in League City, Texas, last October.

Between 1969 and 1972, Apollo astronauts placed seismometers at their landing sites around the moon. The Apollo 12, 14, 15, and 16 instruments faithfully radioed data back to Earth until they were switched off in 1977.

And what did they reveal?

There are at least four different kinds of moonquakes: (1) deep moonquakes about 700 km below the surface, probably caused by tides; (2) vibrations from the impact of meteorites; (3) thermal quakes caused by the expansion of the frigid crust when first illuminated by the morning sun after two weeks of deep-freeze lunar night; and (4) shallow moonquakes only 20 or 30 kilometers below the surface.

The first three were generally mild and harmless. Shallow moonquakes on the other hand were doozies. Between 1972 and 1977, the Apollo seismic network saw twenty-eight of them; a few “registered up to 5.5 on the Richter scale,” says Neal. A magnitude 5 quake on Earth is energetic enough to move heavy furniture and crack plaster.

Furthermore, shallow moonquakes lasted a remarkably long time. Once they got going, all continued more than 10 minutes. “The moon was ringing like a bell,” Neal says.

On Earth, vibrations from quakes usually die away in only half a minute. The reason has to do with chemical weathering, Neal explains: “Water weakens stone, expanding the structure of different minerals. When energy propagates across such a compressible structure, it acts like a foam sponge-it deadens the vibrations.” Even the biggest earthquakes stop shaking in less than 2 minutes.

The moon, however, is dry, cool and mostly rigid, like a chunk of stone or iron. So moonquakes set it vibrating like a tuning fork. Even if a moonquake isn’t intense, “it just keeps going and going,” Neal says. And for a lunar habitat, that persistence could be more significant than a moonquake’s magnitude.

“Any habitat would have to be built of materials that are somewhat flexible,” so no air-leaking cracks would develop. “We’d also need to know the fatigue threshold of building materials,” that is, how much repeated bending and shaking they could withstand.

What causes the shallow moonquakes? And where do they occur? “We’re not sure,” he says. “The Apollo seismometers were all in one relatively small region on the front side of the moon, so we can’t pinpoint [the exact locations of these quakes].” He and his colleagues do have some good ideas, among them being the rims of large and relatively young craters that may occasionally slump.

“We’re especially ignorant of the lunar poles,” Neal continues. That’s important, because one candidate location for a lunar base is on a permanently sunlit region on the rim of Shackleton Crater at the Moon’s south pole.

Neal and his colleagues are developing a proposal to deploy a network of 10 to 12 seismometers around the entire moon, to gather data for at least three to five years. This kind of work is necessary, Neal believes, to find the safest spots for permanent lunar bases.

And that’s just the beginning, he says. Other planets may be shaking, too: “The moon is a technology test bed for establishing such networks on Mars and beyond.”

Original Source: NASA News Release

Dark Lava Floor of Crater Billy

Lunar crater Billy as seen by SMART-1. Ima ge credit: ESA/SPACE-X Click to enlarge
This composite image, taken by the Advanced Moon Imaging Experiment (AMIE) on board ESA’s SMART-1 spacecraft, shows crater Billy at the edge of a large lava plain on the Moon.

The AMIE camera obtained two images in consecutive orbits, from a distance of about 1260 kilometres with a ground resolution of approximately 114 metres per pixel. Each image has a field of view of 56 kilometres.

Crater Billy is located on the southern fringes of the Oceanus Procellarum, on the western half of the Moon’s Earth-facing side (50??bf? West, 13.5??bf? South). It lies to the south-east of the similar-sized crater Hansteen and west-south-west of the lava-flooded crater Letronne.

The Oceanus Procellarum’s southern area is low on spectacle but high in terms of geological interest. An irregular bay, the Mare Humorum on the edge of the ‘ocean’ can be seen below and to the east of the craters Billy and Hansteen.

Billy is an old impact crater, 46 kilometres in diameter, with a rim rising to 1300 metres above its flat floor. The floor of Billy has been flooded by basaltic lava with a low albedo, meaning it leaves a dark surface.

Billy’s floor is one of the darkest spots on the Moon’s face, and can easily be seen any time when it is illuminated, even at full Moon. Billy contrasts with Hansteen, which is light-coloured with a hummocky floor.

Billy is named after the French Jesuit astronomer Jacques de Billy (1602-79), who was one of the first to reject the role of astrology in science, along with superstitious notions about the malevolent influence of comets.

Original Source: ESA Portal

Ski Jumping on the Moon

“Go big or go home.” That’s what aerialists on the US Olympic ski team say, and when they say “big,” they mean it.

Big means “Big Air,” 20 meters above the ground, as high as a five-story building. Aerial skiers fly into the void as fast as a motorcycle speeds down a city street, flipping head over heels, twisting and flipping again. The sky tumbles, but dizziness is not allowed, because only 3 heart-pumping seconds after launch, it’s time to land.

“And you don’t want to land on your ? well ? you know,” says aerial skier and Olympic gold medalist Eric Bergoust: educational video.

He should know. In the sport of aerial skiing, Bergoust has done it all. He was one of the first skiers ever to complete a quad-twist triple flip–four twists and three flips in mid-air. In 1998, hours after a frightening crash in practice, he used the move to win gold at the Nagano Olympic Games. At the time, his score was the highest ever recorded. This year, he’s a top contender again in Torino.

Bergoust has a knack for invention. He has designed new skis to soften the impact of practice landings in swimming pools. He has altered the shape of ski jumps, called “kickers,” to make flights longer-lasting and safer. And his take-off method, raising one arm propeller-style to add twist to his flight, is widely imitated.

His next innovation: “We should jump on the moon! There’s plenty of fresh powder (moondust),” he explains. “And I figure the 1/6 g would give us a lot of hang time.” More hang time means more flips–and more gold.

Consider the following:

On Earth, a typical run begins with Bergoust hurtling down a 23-degree slope. By the time he reaches bottom, 20 meters below the starting gate, he’s traveling almost 70 km/hr?directly into the kicker. From a skier’s point of view, the kicker looks uncomfortably like a wall, but it’s really a ramp guiding the aerialist almost straight up in the air. Bergoust’s favorite kickers are angled at 70 degrees! Up he goes, hanging for nearly 3 seconds before landing in soft snow another 20+ meters beyond the ramp.

see captionNow imagine the same run?same hill, same kicker, same skier?on the moon. Because lunar gravity is less, Bergoust would accelerate downslope at a more gradual pace, reaching bottom with a speed of only 28 km/hr. On Earth, such a slow start would be a disaster. On the moon, it’s perfect. Leaving the kicker at that speed, Bergoust hangs in the “air” for a whopping seven seconds, more than twice his hang-time on Earth: proof.

“I might be able to double my quad-triple,” he says.

Remember, Bergoust won gold in 1998 with a quad-triple. Since then other skiers have added a single twist to his move, turning it into a quint-triple. “Quints” are expected to win the men’s freestyle aerials in Torino. On the moon, Bergoust would have time to add four more twists and three more flips to his routine. “Let’s see?” calculates Bergoust, “that would be an octuple-twist sextuple flip.” Guaranteed gold.

Now for the problems:

skiing on the moonMoondust, although it is powdery, is not as slippery as snow. On the contrary, moondust is very abrasive. It is made of tiny sharp fragments of glass and rock produced by eons of meteoroids pulverizing the moon. Compared to snow, moondust is a “slow surface,” maybe too slow for a good jump.

To combat this, skiers are going to need extra-slick skis coated with Teflon or some other low-friction material. Thin films of diamond might be the answer. Diamond-like carbon films in Earth laboratories rival Teflon in slipperiness, with the advantage of diamond-like hardness to resist the scratching action of sharp-edged dust.

Another problem is the kicker. On Earth, kickers are made of snow. Workers blow snow into large wooden forms laid out at the base of the slope. A spray of water helps the snow stick together and makes the ramp slippery-smooth. Disassemble the forms and?voila!?a kicker.

Imagine the same process on the moon. Workers assemble their form and begin dumping moondust into it. There’s no water hose to squirt the dust to make it stick together. Water exposed to lunar vacuum sublimates (vaporizes) in a flash. So the dust remains dry. Disassemble the forms and?voila!?the kicker slumps into a shapeless pile.

The solution in this case might be a microwave water hose. In labs on Earth, researchers have discovered that grains of moondust cooked in a microwave oven quickly melt and stick together. Spraying moondust with microwaves might allow Olympic workers to mold a good kicker.

And finally?the landing.

On Earth, aerial skiers land on a layer of soft snow, which cushions their impact. On the moon, they’ll land on a layer of soft moondust. Very likely, the dust will spray upwards, coating the skier’s suit.

What’s the problem? Ask any Apollo astronaut. They hated it when moondust got on their spacesuits. Dark dust absorbed sunlight, causing the suit to overheat. Sharp edges of the dust cut into seals, springing leaks. Dust-covered visors were hard to see through. A skier’s suit, thoroughly “dusted,” might be useless after a single run. Another problem to solve….

Bergoust loves solving problems. For years he’s been tinkering with skis, redesigning kickers, inventing new moves, and he’s ready for a new frontier.

“I just need to find a spacesuit!”

Original Source: NASA News Release

Ancient Impact Might Have Created the “Man In The Moon”

The Moon. Image credit: NASA Click to enlarge
Ohio State University planetary scientists have found the remains of ancient lunar impacts that may have helped create the surface feature commonly called the “man in the moon.”

Their study suggests that a large object hit the far side of the moon and sent a shock wave through the moon’s core and all the way to the Earth-facing side. The crust recoiled — and the moon bears the scars from that encounter even today.

The finding holds implications for lunar prospecting, and may solve a mystery about how past impacts on Earth affect it’s geology today.

The early Apollo missions revealed that the moon isn’t perfectly spherical. Its surface is warped in two spots; an earth-facing bulge on the near side is complemented by a large depression on the Moon’s far side. Scientists have long wondered whether these surface features were caused by Earth’s gravity tugging on the moon early in its existence, when its surface was still molten and malleable.

According to Laramie Potts and Ralph von Frese, a postdoctoral researcher and professor of geological sciences respectively at Ohio State , these features are instead remnants from ancient impacts.

Potts and von Frese came to this conclusion after they used gravity fluctuations measured by NASA’s Clementine and Lunar Prospector satellites to map the moon’s interior. They reported the results in a recent issue of the journal Physics of the Earth and Planetary Interiors.

They expected to see defects beneath the moon’s crust that corresponded to craters on the surface. Old impacts, they thought, would have left marks only down to the mantle, the thick rocky layer between the moon’s metallic core and its thin outer crust. And that’s exactly what they saw, at first.

Potts pointed to a cross-sectional image of the moon that the scientists created using the Clementine data. On the far side of the moon, the crust looks as though it was depressed and then recoiled from a giant impact, he said. Beneath the depression, the mantle dips down as he and von Frese would expect it to do if it had absorbed a shock.

Evidence of the ancient catastrophe should have ended there. But some 700 miles directly below the point of impact, a piece of the mantle still juts into the moon’s core today.

That was surprising enough. “People don’t think of impacts as things that reach all the way to the planet’s core,” von Frese said.

But what they saw from the core all the way to the surface on the near side of the moon was even more surprising. The core bulges, as if core material was pushed in on the far side and pulled out into the mantle on the near side. Above that, an outward-facing bulge in the mantle, and above that — on the Earth-facing side of the moon — sits a bulge on the surface.

To the Ohio State scientists, the way these features line up suggests that a large object such as an asteroid hit the far side of the moon and sent a shock wave through the core that emerged on the near side.

The scientists believe that a similar, but earlier impact occurred on the near side.

Potts and von Frese suspect that these events happened about four billion years ago, during a period when the moon was geologically active — with its core and mantle still molten and magma flowing.

Back then, the moon was much closer to the Earth than it is today, Potts explained, so the gravitational interactions between the two were stronger. When magma was freed from the Moon’s deep interior by the impacts, Earth’s gravity took hold of it and wouldn’t let go.

So the warped surfaces on the near and far sides of the moon and the interior features that connect them are all essentially signs of injuries that never healed.

“This research shows that even after the collisions happened, the Earth had a profound effect on the moon,” Potts said.

The impacts may have created conditions that led to a prominent lunar feature.

The “man in the moon” is a collection of dark plains on the Earth-facing side of the moon, where magma from the moon’s mantle once flowed out onto the surface and flooded lunar craters. The moon has long since cooled, von Frese explained, but the dark plains are a remnant of that early active time — “a frozen magma ocean.”

How that magma made it to the surface is a mystery, but if he and Potts are right, giant impacts could have created a geologic “hot spot” on the moon ? a site where magma bubbles to the surface. Some time between when the impacts occurred and when the moon solidified, some magma escaped the mantle through cracks in the crust and flooded the nearside surface and formed a lunar ?hot spot?.

A hot spot on Earth forms the volcanoes that make the Hawaiian island chain. The Ohio State scientists wondered: could similar ancient impacts have penetrated the Earth, and caused the hot spots that exist here today? von Frese thinks that it’s possible.

“Surely Earth was peppered with impacts, too,” he said. “Evidence of impacts here is obscured, but there are hot spots like Hawaii . Some hot spots have corresponding hot spots on the opposite side of the Earth. That could be a consequence of this effect.”

He and Potts are exploring the idea, by studying gravitational anomalies under the Chicxulub Crater on Mexico ‘s Yucatan Peninsula . A giant asteroid struck the spot some 65 million years ago, and is believed to have set off an environmental chain reaction that killed the dinosaurs.

NASA funded this research. The space agency has been charged with returning astronauts to the moon to prospect for valuable gases and minerals.

But even today, scientists don’t entirely know what the moon is made of ? not down to the core, anyway. They can calculate where certain minerals should be, given the conditions they believe existed when the moon formed. But impacts like the one Potts and von Frese discovered have since shuffled materials around. Gravity measurements, they said, will play a key role as scientists figure out what materials lie within the moon, and where.

“We don’t fully understand the way these minerals settle out under temperature and pressure, so the exact composition of the moon is difficult to determine. We have to use gravity measurements to calculate the density of materials, and then use that information to extrapolate the likely composition,” Potts said.

von Frese said a lunar base would be needed before scientists can more completely answer these questions.

Potts agreed. “Once we have more rock samples and soil samples, we will have a lot more to go on. Nothing is better than having a person on the ground,” he said.

Original Source: OSU News Release

The Moon has Alps Too

The lunar Alps border the moon’s Sea of Rains. Image credit: NASA
It’s only a matter of time. One day, winter Olympics will be held on the moon.

The moon’s dust-covered slopes are good places to ski. There’s plenty of powder, moguls and, best of all, low-gravity. With only 1/6th g holding them down, skiers and snowboarders can do tricks they only dreamed of doing on Earth. How about an octuple-twisting quadruple backflip? Don’t worry. Crashes happen in slow-motion, so it won’t hurt so much to wipe out.

And there’s a perfect spot for the Olympic Village: the crater Plato. Most people don’t know it, but Plato of ancient Greece was not only a philosopher, but also an Olympic champion. Twice he won the pankration competition?a grueling mix of boxing and wrestling. A crater named after Plato sounds like a good place for Olympic athletes to stay. The site is flat-bottomed, filled with raw materials for building stadia and habitats, and like Torino, Italy, the site of this year’s games, Plato is near the Alps.

That is, the lunar Alps.

The lunar Alps are a range of mountains on the moon named after the Alps of Europe. They are similar to their Earthly counterparts in height, breath and spectacle. Since the modern Olympics began in 1896, most of the winter games have been held in the Alps. Why should the moon be different?

You can see the lunar Alps using a small backyard telescope. This week is an excellent time to try: Step outside at sundown and look up at the moon. The Olympic Village, crater Plato, is a conspicuous dark oval on the northern shore of Mare Imbrium, the “Sea of Rains.” Your unaided eye is sufficient to see it.

Next, train your telescope on Plato. The Alps begin there. They stretch around the rim of the Sea of Rains from Plato through the spectacular Alpine Valley to towering Mont Blanc. Amateur astronomer Alan Friedman of Buffalo, New York, used a 10-inch telescope to take this picture of the scene.***image4:left***

Although the two Alps look much alike, they formed in different ways:

The Alps of Earth grew over a period of millions of years. Powered by plate tectonics, sections of Earth’s crust pushed together, squeezing the land to produce jagged mountains. The range stretches from France through Italy all the way to Albania; the tallest peak is Mont Blanc, 15,700 ft or 4800 m high.

The Alps of the moon were formed in an instant some 4 billion years ago when a huge asteroid struck. The collision blasted out the Sea of Rains, which, contrary to its name, is a big crater, not a big sea. The Alps are “splash” from the impact.

In those early days, lunar Alps were probably as jagged and rough as the Alps of Earth. But in eons that followed, meteoroids relentlessly pounded the moon, smashing rocks into dust and blunting the sharp edges of mountain peaks. Today’s lunar Alps are a bit shorter (the moon’s Mont Blanc is only 11,800 ft or 3600 m high) and a lot smoother than their terrestrial counterparts?perfect for Olympics.

In the weeks ahead, [email protected] will publish a series of stories exploring the physics of low-gravity Olympics. Is an octuple-twisting quadruple backflip really possible? Should snowboarders be allowed to pilot lunar landers? How is a bobsled like a spaceship? Stay tuned for the answers to these questions and others?with exclusive video from Olympic athletes.

Let the Games begin!

Original Source: NASA News Release

The Smell of Moondust

Apollo 17 astronaut Jack Schmitt, with his spacesuit grayed by moondust. Image credit: NASA Click to enlarge
Moondust. “I wish I could send you some,” says Apollo 17 astronaut Gene Cernan. Just a thimbleful scooped fresh off the lunar surface. “It’s amazing stuff.”

Feel it?it’s soft like snow, yet strangely abrasive.

Taste it?”not half bad,” according to Apollo 16 astronaut John Young.

Sniff it?”it smells like spent gunpowder,” says Cernan.

How do you sniff moondust?

Every Apollo astronaut did it. They couldn’t touch their noses to the lunar surface. But, after every moonwalk (or “EVA”), they would tramp the stuff back inside the lander. Moondust was incredibly clingy, sticking to boots, gloves and other exposed surfaces. No matter how hard they tried to brush their suits before re-entering the cabin, some dust (and sometimes a lot of dust) made its way inside.

Once their helmets and gloves were off, the astronauts could feel, smell and even taste the moon.

The experience gave Apollo 17 astronaut Jack Schmitt history’s first recorded case of extraterrestrial hay fever. “It’s come on pretty fast,” he radioed Houston with a congested voice. Years later he recalls, “When I took my helmet off after the first EVA, I had a significant reaction to the dust. My turbinates (cartilage plates in the walls of the nasal chambers) became swollen.”

Hours later, the sensation faded. “It was there again after the second and third EVAs, but at much lower levels. I think I was developing some immunity to it.”

Other astronauts didn’t get the hay fever. Or, at least, “they didn’t admit it,” laughs Schmitt. “Pilots think if they confess their symptoms, they’ll be grounded.” Unlike the other astronauts, Schmitt didn’t have a test pilot background. He was a geologist and readily admitted to sniffles.

Schmitt says he has sensitive turbinates: “The petrochemicals in Houston used to drive me crazy, and I have to watch out for cigarette smoke.” That’s why, he believes, other astronauts reacted much less than he did.

But they did react: “It is really a strong smell,” radioed Apollo 16 pilot Charlie Duke. “It has that taste — to me, [of] gunpowder — and the smell of gunpowder, too.” On the next mission, Apollo 17, Gene Cernan remarked, “smells like someone just fired a carbine in here.”

Schmitt says, “All of the Apollo astronauts were used to handling guns.” So when they said ‘moondust smells like burnt gunpowder,’ they knew what they were talking about.

To be clear, moondust and gunpowder are not the same thing. Modern smokeless gunpowder is a mixture of nitrocellulose (C6H8(NO2)2O5) and nitroglycerin (C3H5N3O9). These are flammable organic molecules “not found in lunar soil,” says Gary Lofgren of the Lunar Sample Laboratory at NASA’s Johnson Space Center. Hold a match to moondust–nothing happens, at least, nothing explosive.

What is moondust made of? Almost half is silicon dioxide glass created by meteoroids hitting the moon. These impacts, which have been going on for billions of years, fuse topsoil into glass and shatter the same into tiny pieces. Moondust is also rich in iron, calcium and magnesium bound up in minerals such as olivine and pyroxene. It’s nothing like gunpowder.

So why the smell? No one knows.

ISS astronaut Don Pettit, who has never been to the moon but has an interest in space smells, offers one possibility:

“Picture yourself in a desert on Earth,” he says. “What do you smell? Nothing, until it rains. The air is suddenly filled with sweet, peaty odors.” Water evaporating from the ground carries molecules to your nose that have been trapped in dry soil for months.

Maybe something similar happens on the moon.

“The moon is like a 4-billion-year-old desert,” he says. “It’s incredibly dry. When moondust comes in contact with moist air in a lunar module, you get the ‘desert rain’ effect–and some lovely odors.” (For the record, he counts gunpowder as a lovely odor.)

Gary Lofgren has a related idea: “The gases ‘evaporating’ from the moondust might come from the solar wind.” Unlike Earth, he explains, the moon is exposed to the hot wind of hydrogen, helium and other ions blowing away from the sun. These ions hit the moon’s surface and get caught in the dust.

It’s a fragile situation. “The ions are easily dislodged by footsteps or dustbrushes, and they would be evaporated by contact with warm air inside the lunar module. Solar wind ions mingling with the cabin’s atmosphere would produce who-knows-what odors.”

Want to smell the solar wind? Go to the moon.

Schmitt offers yet another idea: The smell, and his reaction to it, could be a sign that moondust is chemically active.

“Consider how moondust is formed,” he says. “Meteoroids hit the moon, reducing rocks to jagged dust. It’s a process of hammering and smashing.” Broken molecules in the dust have “dangling bonds”–unsatisfied electrical connections that need atomic partners.

Inhale some moondust and what happens? The dangling bonds seek partners in the membranes of your nose. You get congested. You report strange odors. Later, when the all the bonds are partnered-up, these sensations fade.

Another possibility is that moondust “burns” in the lunar lander’s oxygen atmosphere. “Oxygen is very reactive,” notes Lofgren, “and would readily combine with the dangling chemical bonds of the moondust.” The process, called oxidation, is akin to burning. Although it happens too slowly for smoke or flames, the oxidation of moondust might produce an aroma like burnt gunpowder. (Note: Burnt and unburnt gunpowder do not smell the same. Apollo astronauts were specific. Moondust smells like burnt gunpowder.)

Curiously, back on Earth, moondust has no smell. There are hundreds of pounds of moondust at the Lunar Sample Lab in Houston. There, Lofgren has held dusty moon rocks with his own hands. He’s sniffed the rocks, sniffed the air, sniffed his hands. “It does not smell like gunpowder,” he says.

Were the Apollo crews imagining things? No. Lofgren and others have a better explanation:

Moondust on Earth has been “pacified.” All of the samples brought back by Apollo astronauts have been in contact with moist, oxygen-rich air. Any smelly chemical reactions (or evaporations) ended long ago.

This wasn’t supposed to happen. Astronauts took special “thermos” containers to the moon to hold the samples in vacuum. But the jagged edges of the dust unexpectedly cut the seals of the containers, allowing oxygen and water vapor to sneak in during the 3-day trip back to Earth. No one can say how much the dust was altered by that exposure.

Schmitt believes “we need to study the dust in situ–on the moon.” Only there can we fully discover its properties: Why does it smell? How does it react with landers, rovers and habitats? What surprises await?

NASA plans to send people back to the moon in 2018, and they’ll stay much longer than Apollo astronauts did. The next generation will have more time and better tools to tackle the mystery.

We’ve only just begun to smell the moondust.

Original Source: NASA News Release