Category: Moon

The surface of the Moon is exposed to space radiation. Image credit: NASA Click to enlarge
On the Moon, many of the things that can kill you are invisible: breathtaking vacuum, extreme temperatures and space radiation top the list.

Vacuum and temperature NASA can handle; spacesuits and habitats provide plenty of air and insulation. Radiation, though, is trickier.

The surface of the Moon is baldly exposed to cosmic rays and solar flares, and some of that radiation is very hard to stop with shielding. Furthermore, when cosmic rays hit the ground, they produce a dangerous spray of secondary particles right at your feet. All this radiation penetrating human flesh can damage DNA, boosting the risk of cancer and other maladies.

According to the Vision for Space Exploration, NASA plans to send astronauts back to the Moon by 2020 and, eventually, to set up an outpost. For people to live and work on the Moon safely, the radiation problem must be solved.

“We really need to know more about the radiation environment on the Moon, especially if people will be staying there for more than just a few days,” says Harlan Spence, a professor of astronomy at Boston University.

To carefully measure and map the Moon’s radiation environment, NASA is developing a robotic probe to orbit the Moon beginning in 2008. Called the Lunar Reconnaissance Orbiter (LRO), this scout will pave the way for future human missions not only by measuring space radiation, but also by hunting for frozen water and mapping the Moon’s surface in unprecedented detail. LRO is a key part of NASA’s Robotic Lunar Exploration Program, managed by the Goddard Space Flight Center.

One of the instruments onboard LRO is the Cosmic Ray Telescope for the Effects of Radiation (CRaTER).

“Not only will we measure the radiation, we will use plastics that mimic human tissue to look at how these highly energetic particles penetrate and interact with the human body,” says Spence, who is the Principal Investigator for CRaTER.

By placing the radiation detectors in CRaTER behind various thicknesses of a special plastic that has similar density and composition to human tissue, Spence and his colleagues will provide much-needed data: Except for quick trips to the Moon during the Apollo program, most human spaceflight has occurred near Earth where our planet’s magnetic field provides a natural shield. In low-Earth orbit, the most dangerous forms of space radiation are relatively rare. That’s good for astronauts, but it leaves researchers with many unanswered questions about what radiation does to human tissue. CRaTER will help fill in the gaps.

Out in deep space, radiation comes from all directions. On the Moon, you might expect the ground, at least, to provide some relief, with the solid body of the Moon blocking radiation from below. Not so.

When galactic cosmic rays collide with particles in the lunar surface, they trigger little nuclear reactions that release yet more radiation in the form of neutrons. The lunar surface itself is radioactive!

So which is worse for astronauts: cosmic rays from above or neutrons from below? Igor Mitrofanov, a scientist at the Institute for Space Research and the Russian Federal Space Agency, Moscow, offers a grim answer: “Both are worse.”

Mitrofanov is Principle Investigator for the other radiation-sensing instrument on LRO, the Lunar Exploration Neutron Detector (LEND), which is partially funded by the Russian Federal Space Agency. By using an isotope of helium that’s missing one neutron, LEND will be able to detect neutron radiation emanating from the lunar surface and measure how energetic those neutrons are.

The first global mapping of neutron radiation from the Moon was performed by NASA’s Lunar Prospector probe in 1998-99. LEND will improve on the Lunar Prospector data by profiling the energies of these neutrons, showing what fraction are of high energy (i.e., the most damaging to people) and what fraction are of lower energies.

With such knowledge in hand, scientists can begin designing spacesuits, lunar habitats, Moon vehicles, and other equipment for NASA’s return to the Moon knowing exactly how much radiation shielding this equipment must have to keep humans safe.

NASA News Release

Hadley Rille on the Moon. Image credit: ESA/Space-X. Click to enlarge
This image, taken by the Advanced Moon Micro-Imager Experiment (AMIE) on board ESA?s SMART-1 spacecraft, shows the Hadley Rille on the south-east edge of Mare Imbrium on the Moon.

AMIE obtained this image from an altitude of about 2000 kilometres. It covers an area of about 100 kilometres and shows the region around Hadley Rille centred at approximately 25? North and 3? East.
The sinuous rille follows a course generally to the north-east toward the peak of Mount Hadley, after which it is named (bright feature, top right). To the east of this rille, south-west of Mount Hadley, is Mount Hadley Delta, one of the largest Appenine mountains.

The Appenine mountains mark the edge of the impact basin holding Mare Imbrium, rising between 1800 and 4500 metres above the mare. They are the bright bumps in the lower half of the image.

The valley between these two peaks is fairly well known because NASA astronauts David R. Scott and James B. Irwin landed there during the Apollo 15 mission in 1971. The landing site is near the upper right part of the rille (26.1? North and 3.9? East) on a dark mare plain called Palus Putredinis (Marsh of Decay).

The rille begins at the curved gash on the left side of this image, and is seen clearest in the rectangular, mare-floored valley in the centre of the image. It is over 120 kilometres long, and up to 1500 metres across and over 300 metres deep in places.

The rille formed nearly 3300 million years ago. In contrast, lava channels on Hawaii are usually under 10 kilometres long and are only 50-100 metres wide. The Hadley C crater next to the rille is about 5 kilometres in diameter.

Sinuous rilles are probably the most recognisable of small volcanic features on the Moon. Many partially resemble river valleys on Earth. However, the lunar rilles usually flow away from small pit structures.

The rilles mark lava channels or collapsed lava tubes that formed during mare volcanism. Indeed, the lunar samples indicate that the Moon has always been dry, thus confirming the volcanic origin of the rilles.

Still, in some cases, the lunar flows may have melted their way down into older rocks, much like rivers cut into their flood plains on Earth. Similar lava channels and tubes are found in Hawaii, but these are all much, much smaller than those found on the Moon, indication that the very low lunar gravity has a strong influence on morphological processes.

Original Source: ESA Portal

Apollo 17 rover on the Moon. Image credit: NASA. Click to enlarge.
Inside the lunar lander Challenger, a radio loudspeaker crackled.

Houston: “We’ve got you on television now. We have a good picture.”

Gene Cernan, Apollo 17 commander: “Glad to see old Rover’s still working.”

“Rover,” the moon buggy, sat outside with no one in the driver’s seat, its side-mounted TV camera fixed on Challenger. Back in Houston and around the world, millions watched. The date was Dec. 19, 1972, and history was about to be made.

Suddenly, soundlessly, Challenger split in two (movie). The base of the ship, the part with the landing pads, stayed put. The top, the lunar module with Cernan and Jack Schmitt inside, blasted off in a spray of gold foil. It rose, turned, and headed off to rendezvous with the orbiter America, the craft that would take them home again.

Those were the last men on the Moon. After they were gone, the camera panned back and forth. There was no one there, nothing, only the rover, the lander and some equipment scattered around the dusty floor of the Taurus-Littrow valley. Eventually, Rover’s battery died and the TV transmissions stopped.

That was our last good look at an Apollo landing site.

Many people find this surprising, even disconcerting. Conspiracy theorists have long insisted that NASA never went to the Moon. It was all a hoax, they say, a way to win the Space Race by trickery. The fact that Apollo landing sites have not been photographed in detail since the early 1970s encourages their claims.

And why haven’t we photographed them? There are six landing sites scattered across the Moon. They always face Earth, always in plain view. Surely the Hubble Space Telescope could photograph the rovers and other things astronauts left behind. Right?

Wrong. Not even Hubble can do it. The Moon is 384,400 km away. At that distance, the smallest things Hubble can distinguish are about 60 meters wide. The biggest piece of left-behind Apollo equipment is only 9 meters across and thus smaller than a single pixel in a Hubble image.

Better pictures are coming. In 2008 NASA’s Lunar Reconnaissance Orbiter will carry a powerful modern camera into low orbit over the Moon’s surface. Its primary mission is not to photograph old Apollo landing sites, but it will photograph them, many times, providing the first recognizable images of Apollo relics since 1972.

The spacecraft’s high-resolution camera, called “LROC,” short for Lunar Reconnaissance Orbiter Camera, has a resolution of about half a meter. That means that a half-meter square on the Moon’s surface would fill a single pixel in its digital images.

Apollo moon buggies are about 2 meters wide and 3 meters long. So in the LROC images, those abandoned vehicles will fill about 4 by 6 pixels.

What does a half-meter resolution picture look like? This image of an airport on Earth has the same resolution as an LROC image. Moon buggy-sized objects (automobiles and luggage carts) are clear:

“I would say the rovers will look angular and distinct,” says Mark Robinson, research associate professor at Northwestern University in Evanston, Illinois, and Principal Investigator for LROC. “We might see some shading differences on top from seats, depending on the sun angle. Even the rovers’ tracks might be detectable in some instances.”

Even more recognizable will be the discarded lander platforms. Their main bodies are 4 meters on a side, and so will fill an 8 by 8 pixel square in the LROC images. The four legs jutting out from the platforms’ four corners span a diameter of 9 meters. So, from landing pad to landing pad, the landers will occupy about 18 pixels in LROC images, more than enough to trace their distinctive shapes.

Shadows help, too. Long black shadows cast across gray lunar terrain will reveal the shape of what cast them: the rovers and landers. “During the course of its year-long mission, LROC will image each landing site several times with the sunlight at different angles each time,” says Robinson. Comparing the different shadows produced would allow for a more accurate analysis of the shape of the objects.

Enough nostalgia. LROC’s main mission is about the future. According to NASA’s Vision for Space Exploration, astronauts are returning to the Moon no later than 2020. Lunar Reconnaissance Orbiter is a scout. It will sample the Moon’s radiation environment, search for patches of frozen water, make laser maps of lunar terrain and, using LROC, photograph the Moon’s entire surface. By the time astronauts return, they’ll know the best places to land and much of what awaits them.

Two high-priority targets for LROC are the Moon’s poles.

“We’re particularly interested in the poles as a potential location for a moon base,” Robinson explains. “There are some cratered regions near the poles that are in shadow year-round. These places might be cold enough to harbor permanent deposits of water ice. And nearby are high regions that are sunlit all year. With constant sunlight for warmth and solar power, and a potential source of water nearby, these high regions would make an ideal location for a base.” Data from LROC will help pinpoint the best ridge or plateau for setting up a lunar home.

Once a moonbase is established, what’s the danger of it being hit by a big meteorite? LROC will help answer that question.

“We can compare LROC images of the Apollo landing sites with Apollo-era photos,” says Robinson. The presence or absence of fresh craters will tell researchers something about the frequency of meteor strikes.

LROC will also be hunting for ancient hardened lava tubes. These are cave-like places, hinted at in some Apollo images, where astronauts could take shelter in case of an unexpected solar storm. A global map of these natural storm shelters will help astronauts plan their explorations.

No one knows what else LROC might find. The Moon has never been surveyed in such detail before. Surely new things await; old abandoned spaceships are just the beginning.

Original Source: NASA News Release

SMART-1’s detection of calcium, iron and other elements on the Moon. Image credit: ESA. Click to enlarge.
Thanks to measurements by the D-CIXS X-ray spectrometer, ESA?s SMART-1 spacecraft has made the first ever unambiguous remote-sensing detection of calcium on the Moon.

SMART-1 is currently performing the verification and calibration of its instruments, while it runs along its science orbit, reaching 450 kilometres from the Moon at its closest distance. During this calibration phase, which precedes the actual science observations phase, the SMART-1 scientists are getting acquainted with the delicate operations and the performance of their instruments in the warm environment of the lunar orbit.

Although it is still preparing for full lunar operations, D-CIXS has started already sending back high-quality data. D-CIXS is designed to measure the global composition of the Moon by observing how it glows in X-rays when the Sun shines on it. In fact, different chemical elements provide their ‘fingerprinting’, each glowing in a unique way.

On 15 January 2005, between 07:00 and about 09:00 Central European Time, a solar flare occurred, blasting a quantity of radiation that flooded the Solar System and the Moon. “The Sun was kind to us”, said Prof Manuel Grande of the Rutherford Appleton Laboratory, leader of the D-CIXS instrument team. “It set off a large X-ray flare just as we took our first look downwards at the lunar surface”.

The lunar surface reacts to the incoming solar radiation by glowing in different X-ray wavelengths. This enabled D-CIXS, , to distinguish the presence of chemical elements – including calcium, aluminium, silicon and iron – in Mare Crisium, the area of the lunar surface being observed at that moment. “It is the first time ever that calcium has been unambiguously detected on the Moon by remote-sensing instrumentation”, added Prof. Grande. Calcium is an important rock-forming element on the Moon.

“Even before our scientists have finished setting up the instruments, SMART-1 is already producing brand new lunar science”, said Bernard Foing, SMART-1 Project Scientist. “When we get D-CIXS and the other instruments fully tuned, with scientific data rolling in routinely, we should have a truly ground-breaking mission”.

Original Source: ESA News Release

The Moon and its dark spots. Image credit: NASA. Click to enlarge.
People of every culture have been fascinated by the dark “spots” on the Moon, which seem to compose the figure of a rabbit, frogs or the face of a clown. With the Apollo missions, scientists found that these features are actually huge impact basins that were flooded with now-solidified lava. One surprise was that these basins formed relatively late in the history of the early solar system – approximately 700 million years after the formation of the Earth and Moon. Many scientists now believe that these lunar impact basins bear witness to a huge spike in the bombardment rate of the planets – called the late heavy bombardment (LHB). The cause of such an intense bombardment, however, is considered by many to be one of the best-preserved mysteries of solar system history.

In a series of three papers published in this week’s issue of the journal Nature, an international team of planetary scientists, Rodney Gomes (National Observatory of Brazil), Harold Levison (Southwest Research Institute, United States), Alessandro Morbidelli (Observatoire de la C?te d’Azur, France) and Kleomenis Tsiganis (OCA and University of Thessaloniki, Greece) – brought together by a visitor program hosted at the Observatoire de la C?te d’Azur in Nice – proposed a model that not only naturally solves the mystery of the origin of the LHB, but also explains many of the observed characteristics of the outer planetary system.

This new model envisions that the four giant planets, Jupiter, Saturn, Uranus and Neptune, formed in a very compact orbital configuration, which was surrounded by a disk of small objects made of ice and rock (known as “planetesimals”). Numerical simulations by the Nice team shows that some of these planetesimals slowly leaked out of the disk due to the gravitational effects of the planets. The planets scattered these smaller objects throughout the solar system, sometimes outward and sometimes inward.

“As Isaac Newton taught us, for every action there is an equal and opposite reaction,” says Tsiganis. “If a planet throws a planetesimal out of the solar system, the planet moves toward the Sun, just a tiny bit, in compensation. If, on the other hand, the planet scatters the planetesimal inward, the planet jumps slightly farther from the Sun.”

Numerical simulations show that, on average, Jupiter moved inward while the other giant planets moved outward.

Initially, this was a very slow process, taking millions of years for the planets to move a small amount. Then, according to this new model, after 700 million years, the situation suddenly changed. At that time, Saturn migrated through the point where its orbital period was exactly twice that of Jupiter’s. This special orbital configuration caused Jupiter’s and Saturn’s orbits to suddenly become more elliptical.

“This caused the orbits of Uranus and Neptune to go nuts,” says Gomes. “Their orbits became very eccentric and they started to gravitationally scatter off each other – and Saturn too.”

The Nice team argues that this evolution of Uranus’ and Neptune’s orbits caused the LHB on the Moon. Their computer simulations show that these planets very quickly penetrated the planetesimal disk, scattering objects throughout the planetary system. Many of these objects entered the inner solar system where they peppered the Earth and Moon with impacts. In addition, the whole process destabilized the orbits of asteroids, which then would have also contributed to the LHB. Finally, the gravitational effects of the planetesimal disk caused Uranus and Neptune to evolve onto their current orbits.

“It’s very convincing,” says Levison. “We have made several dozen simulations of this process, and statistically the planets ended up on orbits very similar to the ones that we see, with the correct separations, eccentricities and inclinations. So, in addition to the LHB, we can also explain the orbits of the giant planets. No other model has ever accomplished either thing before.”

However, there was one more hurdle to overcome. The solar system currently contains a population of asteroids that follow essentially the same orbit as Jupiter, but lead or trail that planet by an angular distance of roughly 60 degrees. Computer simulations show that these bodies, known as the “Trojan asteroids,” would have been lost as the giant planets’ orbits changed.

“We sat around for months worrying about this problem, which seemed to invalidate our model,” says Morbidelli, “until we realized that if a bird can escape from an open cage, another one can come and nest in it.”

The Nice team found that some of the very objects that were driving the planetary evolution, and which caused the LHB, would also have been captured into Trojan asteroid orbits. In the simulations, the trapped Trojans turned out to reproduce the orbital distribution of the observed Trojans, which was unexplained up to now. The total predicted mass of the trapped objects was also consistent with the observed population.

Taken in total, the Nice team’s new model naturally explains the orbits of the giant planets, the Trojan asteroids and the LHB to unprecedented accuracy. “Our model explains so many things that we believe it must be basically correct,” says Mordibelli. “The structure of the outer solar system shows that the planets probably went through a shake up well after the planet formation process ended.”

Original Source: SWRI News Release

Astronauts in a lunar base will need a lot of air. Image credit: NASA. Click to enlarge.
NASA, in collaboration with the Florida Space Research Institute (FSRI), today announced a new Centennial Challenges prize competition.

The MoonROx (Moon Regolith Oxygen) challenge will award $250,000 to the first team that can extract breathable oxygen from simulated lunar soil before the prize expires on June 1, 2008.

For the MoonROx challenge, teams must develop hardware within mass and power limits that can extract at least five kilograms of breathable oxygen from simulated lunar soil during an eight-hour period. The soil simulant, called JSC-1, is derived from volcanic ash. The oxygen production goals represent technologies that are beyond existing state-of-the-art.

NASA’s Centennial Challenges promotes technical innovation through a novel program of prize competitions. It is designed to tap the nation’s ingenuity to make revolutionary advances to support the Vision for Space Exploration and NASA goals.

“The use of resources on other worlds is a key element of the Vision for Space Exploration,” said NASA’s Associate Administrator for the Exploration Systems Mission Directorate, Craig Steidle. “This challenge will reach out to inventors who can help us achieve the Vision sooner,” he added.

“This is our third prize competition, and the Centennial Challenges program is getting more and more exciting with each new announcement. The innovations from this competition will help support long-duration, human and robotic exploration of the moon and other worlds,” said Brant Sponberg, NASA’s Centennial Challenges program manager.

“Oxygen extraction technologies will be critical for both robotic and human missions to the moon,” said FSRI Executive Director Sam Durrance. “Like other space-focused prize competitions, the MoonROx challenge will encourage a broad community of innovators to develop technologies that expand our capabilities,” he added.

The Centennial Challenges program is managed by NASA’s Exploration Systems Mission Directorate. FSRI is a state-wide center for space research. It was established by Florida’s governor and legislature in 1999.

For more information about Centennial Challenges on the Internet, visit: http://centennialchallenges.nasa.gov

For more information about NASA and agency programs on the Internet, visit: http://www.nasa.gov/home/index.html

For information about the Florida Space Research Institute on the Internet, visit: http://www.fsri.org

Original Source: NASA News Release

NASA is gearing up to send humans back to the Moon. Image credit: Pat Rawlings / SAIC. Click to enlarge.
The next time you look at the Moon, pause for a moment and let this thought sink in: People have actually walked on the Moon, and right now the wheels are in motion to send people there again.

The goals this time around are more ambitious than they were in the days of the Apollo program. NASA’s new Vision for Space Exploration spells out a long-term strategy of returning to the Moon as a step toward Mars and beyond. The Moon, so nearby and accessible, is a great place to try out new technologies critical to living on alien worlds before venturing across the solar system.

Whether a moonbase will turn out to be feasible hinges largely on the question of water. Colonists need water to drink. They need water to grow plants. They can also break water apart to make air (oxygen) and rocket fuel (oxygen+hydrogen). Furthermore, water is surprisingly effective at blocking space radiation. Surrounding the ‘base with a few feet of water would help protect explorers from solar flares and cosmic rays.

The problem is, water is dense and heavy. Carrying large amounts of it from Earth to the Moon would be expensive. Settling the Moon would be so much easier if water were already there.

It’s possible: Astronomers believe that comets and asteroids hitting the Moon eons ago left some water behind. (Earth may have received its water in the same way.) Water on the Moon doesn’t last long. It evaporates in sunlight and drifts off into space. Only in the shadows of deep cold craters could you expect to find any, frozen and hidden. And indeed there may be deposits of ice in such places. In the 1990s two spacecraft, Lunar Prospector and Clementine, found tantalizing signs of ice in shadowed craters near the Moon’s poles–perhaps as much as much as a cubic kilometer. The data were not conclusive, though.

To find out if lunar ice is truly there, NASA plans to send a robotic scout. The Lunar Reconnaissance Orbiter, or “LRO” for short, is scheduled to launch in 2008 and to orbit the Moon for a year or more. Carrying six different scientific instruments, LRO will map the lunar environment in greater detail than ever before.

“This is the first in a string of missions,” says Gordon Chin, project scientist for LRO at NASA’s Goddard Space Flight Center. “More robots will follow, about one per year, leading up to manned flight” no later than 2020.

LRO’s instruments will do many things: they’ll map and photograph the Moon in detail, sample its radiation environment and, not least, hunt for water.

For example, the spacecraft’s Lyman-Alpha Mapping Project (LAMP), will attempt to peer into the darkness of permanently shadowed craters at the Moon’s poles, looking for signs of ice hiding there.

How can LAMP see in the dark? By looking for the dim glow of reflected starlight.

LAMP senses a special range of ultraviolet light wavelengths. Not only is starlight relatively bright in this range, but also the hydrogen gas that permeates the universe radiates in this range as well. To LAMP’s sensor, space itself is literally aglow in all directions. This ambient lighting may be enough to see what lies in the inky blackness of these craters.

“What’s more, water ice has a characteristic spectral ‘fingerprint’ in this same range of ultraviolet light, so we’ll get spectral evidence of whether ice is in these craters,” explains Alan Stern, a scientist at the Southwest Research Institute and principal investigator for LAMP.

The spacecraft is also equipped with a laser that can shine pulses of light into dark craters. The main purpose of the instrument, called the Lunar Orbiter Laser Altimeter (LOLA), is to produce a highly accurate contour map of the entire Moon. As a bonus, it will also measure the brightness of each laser reflection. If the soil contains ice crystals, as little as 4%, the returning pulse would be noticeably brighter.

LOLA by itself can’t prove that ice is there. “Any kind of reflective crystals could produce brighter pulses,” explains David Smith, principal investigator for LOLA at NASA’s Goddard Space Flight Center. “But if we see brighter pulses only in these permanent shadows, we’d strongly suspect ice.”

One of LRO’s instruments, named Diviner, will map the temperature of the Moon’s surface. Scientists can use these measurements to search for places where ice could exist. Even in the permanent shadows of polar craters, temperatures must be very low for ice to resist evaporation. Thus, Diviner will provide a “reality check” for LRO’s other ice-sensitive instruments, identifying areas where positive signs of ice would not make any sense because the temperature is simply too high.

Another reality check will come from LRO’s Lunar Exploration Neutron Detector (LEND), which counts neutrons spraying out of the lunar surface. Why does the Moon emit neutrons? And what does that have to do with water? The Moon is constantly bombarded by cosmic rays, which produce neutrons when they hit the ground. Hydrogen-bearing compounds like H2O absorb neutrons, so a dip in neutron radiation could signal an oasis … of sorts. LEND is being developed by Igor Mitrofanov from the Institute for Space Research, Federal Space Agency, Moscow.

“There’s a strong synergy between the various instruments on LRO,” notes Chin. “None of these instruments alone could provide definitive evidence of ice on the Moon, but if they all point to ice in the same area, that would be compelling.”

Chin also points out another reason that finding ice near the Moon’s poles would be exciting:

Not far from some permanently shadowed craters are mountainous regions in permanent sunlight, known romantically as “peaks of eternal sunshine.” Conceivably, a moonbase could be placed on one of those peaks, providing astronauts with constant solar power–not far from crater-valleys below, rich in ice and ready to be mined.

Wishful thinking? Or a reasonable plan? Lunar Reconnaissance Orbiter will beam back the answer.

Original Source: Science@NASA Story

This is a true story.

In 1972, Apollo astronaut Harrison Schmidt sniffed the air in his Lunar Module, the Challenger. “[It] smells like gunpowder in here,” he said. His commander Gene Cernan agreed. “Oh, it does, doesn’t it?”

The two astronauts had just returned from a long moonwalk around the Taurus-Littrow valley, near the Sea of Serenity. Dusty footprints marked their entry into the spaceship. That dust became airborne–and smelly.

Later, Schmidt felt congested and complained of “lunar dust hay fever.” His symptoms went away the next day; no harm done. He soon returned to Earth and the anecdote faded into history.

But Russell Kerschmann never forgot. He’s a pathologist at the NASA Ames Research Center studying the effects of mineral dust on human health. NASA is now planning to send people back to the Moon and on to Mars. Both are dusty worlds, extremely dusty. Inhaling that dust, says Kerschmann, could be bad for astronauts.

“The real problem is the lungs,” he explains. “In some ways, lunar dust resembles the silica dust on Earth that causes silicosis, a serious disease.” Silicosis, which used to be called “stone-grinder’s disease,” first came to widespread public attention during the Great Depression when hundreds of miners drilling the Hawk’s Nest Tunnel through Gauley Mountain in West Virginia died within half a decade of breathing fine quartz dust kicked into the air by dry drilling–even though they had been exposed for only a few months. “It was one of the biggest occupational-health disasters in U.S. history,” Kerschmann says.

This won’t necessarily happen to astronauts, he assures, but it’s a problem we need to be aware of–and to guard against.

Quartz, the main cause of silicosis, is not chemically poisonous: “You could eat it and not get sick,” he continues. “But when quartz is freshly ground into dust particles smaller than 10 microns (for comparison, a human hair is 50+ microns wide) and breathed into the lungs, they can embed themselves deeply into the tiny alveolar sacs and ducts where oxygen and carbon dioxide gases are exchanged.” There, the lungs cannot clear out the dust by mucous or coughing. Moreover, the immune system’s white blood cells commit suicide when they try to engulf the sharp-edged particles to carry them away in the bloodstream. In the acute form of silicosis, the lungs can fill with proteins from the blood, “and it’s as if the victim slowly suffocates” from a pneumonia-like condition.

Lunar dust, being a compound of silicon as is quartz, is (to our current knowledge) also not poisonous. But like the quartz dust in the Hawk’s Nest Tunnel, it is extremely fine and abrasive, almost like powdered glass. Astronauts on several Apollo missions found that it clung to everything and was almost impossible to remove; once tracked inside the Lunar Module, some of it easily became airborne, irritating lungs and eyes.

Martian dust could be even worse. It’s not only a mechanical irritant but also perhaps a chemical poison. Mars is red because its surface is largely composed of iron oxide (rust) and oxides of other minerals. Some scientists suspect that the dusty soil on Mars may be such a strong oxidizer that it burns any organic compound such as plastics, rubber or human skin as viciously as undiluted lye or laundry bleach.

“If you get Martian soil on your skin, it will leave burn marks,” believes University of Colorado engineering professor Stein Sture, who studies granular materials like Moon- and Mars-dirt for NASA. Because no soil samples have ever been returned from Mars, “we don’t know for sure how strong it is, but it could be pretty vicious.”

Moreover, according to data from the Pathfinder mission, Martian dust may also contain trace amounts of toxic metals, including arsenic and hexavalent chromium–a carcinogenic toxic waste featured in the docudrama movie Erin Brockovich (Universal Studios, 2000). That was a surprising finding of a 2002 National Research Council report called Safe on Mars: Precursor Measurements Necessary to Support Human Operations on the Martian Surface.

The dust challenge would be especially acute during windstorms that occasionally envelop Mars from poles to equator. Dust whips through the air, scouring every exposed surface and sifting into every crevice. There’s no place to hide.

To find ways of mitigating these hazards, NASA is soon to begin funding Project Dust, a four-year study headed by Masami Nakagawa, associate professor in the mining engineering department of the Colorado School of Mines. Project Dust will study such technologies as thin-film coatings that repel dust from tools and other surfaces, and electrostatic techniques for shaking or otherwise removing dust from spacesuits.

These technologies, so crucial on the Moon and Mars, might help on Earth, too, by protecting people from sharp-edged or toxic dust on our own planet. Examples include alkaline dust blown from dry lakes in North American deserts, wood dust from sawmills and logging operations, and, of course, abrasive quartz dust in mines.

The road to the stars is surprisingly dusty. But, says Kerschmann, “I strongly believe it’s a problem that can be controlled.”

Original Source: Science@NASA Story

The first object in the night sky most of us ever saw, the Moon remains a mystery. Haunted by poets, looked upon by youngsters in love, studied intensely by astronomers for four centuries, examined by geologists for the last 50 years, walked upon by twelve humans, this is Earth’s satellite.

And as we look towards the Moon with thoughts of setting up a permanent home there, one new question is paramount: does the Moon have water? Although none has been definitely detected, recent evidence suggests that it’s there.

Why should there be water on the Moon? Simply for the same reason that there’s water on Earth. A favorite theory is that water, either as water by itself or as its components of hydrogen and oxygen, was deposited on Earth during its early history–mostly during a period of “late heavy bombardment” 3.9 billion years ago–by the impacts of comets and asteroids. Because the Moon shares the same area of space as Earth, it should have received its share of water as well. However, since it has only a tiny fraction of Earth’s gravity, most of the Moon’s water supply should have evaporated and drifted off into space long ago. Most, but perhaps not all.

In ancient times, observers commonly thought the Moon had abundant water–in fact, the great lava plains like Mare Imbrium were called maria, or seas. But when Neil Armstrong and Buzz Aldrin landed on the Moon in 1969, they stepped out not into the water of the Sea of Tranquillity, but onto basaltic rock. No one was surprised by that–the idea of lunar maria had been replaced by lava plains decades earlier.

As preparations were underway in the mid 1960s for the Apollo program, questions about water on the Moon were barely on the radar screen. Geologists and astronomers were divided at the time as to whether the lunar surface was a result of volcanic forces from beneath, or cosmic forces from above. Grove Carl Gilbert in 1893 already had the answer. That famous geologist suggested that large asteroidal objects hit the Moon, forming its craters. Ralph Baldwin articulated the same idea in 1949, and Gene Shoemaker revived the idea again around 1960. Shoemaker, almost alone among geologists of his day, saw the Moon as a fertile subject for field geology. He saw the craters on the Moon as logical impact sites that were formed not gradually in eons, but explosively in seconds.

The Apollo flights confirmed that the dominant geological process on the Moon is impact-related. That discovery, in turn, ushered in a new question: Since Earth’s water was probably delivered largely by comets and asteroids, could this process have done the same for the Moon? And could some of that water still be there?

In 1994, the SDI-NASA Clementine spacecraft orbited the Moon and mapped its surface. In one experiment, Clementine beamed radio signals into shadowed craters near the Moon’s south pole. The reflections, received by antennas on Earth, seemed to come from icy material.

That makes sense. If there is water on the Moon, it’s probably hiding in the permanent shadows of deep, cold craters, safe from vaporizing sunlight, frozen solid.

So far so good, but… the Clementine data were not conclusive, and when astronomers tried to find ice in the same craters using the giant Arecibo radar in Puerto Rico, they couldn’t. Maybe Clementine was somehow wrong.

In 1998, NASA sent another spacecraft, Lunar Prospector, to check. Using a device called a neutron spectrometer, Lunar Prospector scanned the Moon’s surface for hydrogen-rich minerals. Once again, polar craters yielded an intriguing signal: neutron ratios indicated hydrogen. Could it be the “H” in H2O? Many researchers think so.

Lunar Prospector eventually sacrificed itself to the search. When the spacecraft’s primary mission was finished, NASA decided to crash Prospector near the Moon’s south pole, hoping to liberate a bit of its meager layer of water. Earth’s satellite might briefly become a comet as amounts of water vapor were released.

Lunar Prospector crashed, as planned, and several teams of researchers tried to detect that cloud, but without success. Either there was no water, or there was not enough water to be detected by Earth-based telescopes, or the telescopes were not looking in precisely the right place. In any event, no water was found from Prospector’s impact.

In 2008, NASA plans to send a new spacecraft to the Moon: the Lunar Reconnaissance Orbiter (LRO), bristling with advanced sensors that can sense water in at least four different ways. Scientists are hopeful that LRO can decide the question of Moon water once and for all.

Our interest is not just scientific. If we are indeed to build a base on the Moon, the presence of water already there would offer a tremendous advantage in building and running it. It’s been 35 years since we first set foot on the Moon. Now ambitious eyes once again look toward our satellite not just as a place to visit, but as a place to live.

Original Source: Science@NASA

ESA?s SMART-1 mission to the Moon has been monitoring the illumination of lunar poles since the beginning of 2005, about two months before arriving at its final science orbit.

Ever since, the AMIE on-board camera has been taking images which are even able to show polar areas in low illumination conditions. Images like these will help identify if peaks of eternal light exist at the poles.

SMART-1 took views of the North Polar Region from a distance of 5000 km during a pause in the spiralling descent to the science orbit. One can see highland terrains, very highly cratered due to their old age. The rims of the large craters project very long shadows even on surrounding features. SMART-1 is monitoring the polar shadows cast during the Moon rotation, and their seasonal variations, to look for places with long-lasting illumination.

The image shows a 275 km area close to the North pole (upper left corner) observed by SMART-1 on 29 December 2004 from a distance of 5500 km. This shows a heavily cratered highland terrain, and is used to monitor illumination of polar areas, and long shadows cast by large crater rims.

SMART-1 also observated a North polar area 250 km wide on 19 January 2005 (close to North winter solstice) from a distance of 5000 km. The illuminated part of crater rim is very close to the North pole and is a candidate for a peak of eternal sunlight.

?This shows the ability of SMART-1 and its camera to image even for low light levels at the poles and prospect for sites for future exploration?, says AMIE camera Principal Investigator Jean-Luc Josset, (SPACE-X, Switzerland).

?If we can confirm peaks of eternal light?, adds Bernard Foing, SMART-1 Project Scientist, ?these could be a key locations for possible future lunar outposts?.

The existence of peaks of eternal light at the poles, that is areas that remain eternally illuminated regardless of seasonal variations, was first predicted in the second half of the nineteenth century by the astronomer Camille Flammarion. Even if for most of the Moon the length of the day does not vary perceptibly during the course of seasons, this is not the case over the poles, where illumination can vary extensively during the course of the year. The less favourable illumination conditions occur around the northern winter solstice, around 24 January. There are areas at the bottom of near-polar craters that do not see direct sunshine, where ice might potentially be trapped. Also there are areas at higher elevation on the rim of polar craters that see the Sun more than half of the time. Eventually, there may be areas that are always illuminated by sunlight.

Original Source: ESA News Release