NASA LRO: Gravity anomalies bordering the Moon's Procellarum region

The Lunar Orbiter Laser Altimeter (LOLA), aboard NASA's Lunar Reconnaissance Orbiter (LRO), collected data to produce this image showing the topography of Earth’s moon. 

Gravity anomalies bordering the Procellarum region appear superimposed in blue. 

The image depicts border structures using gravity gradients calculated with information obtained by NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission. 

Researchers interpret these gravity anomalies as ancient lava-flooded rift zones buried beneath the volcanic plains (or maria) on the nearside of the moon.

Credit: NASA

More Information
"Structure and evolution of the lunar Procellarum region as revealed by GRAIL gravity data"
Jeffrey C. Andrews-Hanna, Jonathan Besserer James W. Head III, Carly J. A. Howett, Walter S. Kiefer, Paul J. Lucey, Patrick J. McGovern, H. Jay Melosh, Gregory A. Neumann, Roger J. Phillips, Paul M. Schenk, David E. Smith, Sean C. Solomon & Maria T. Zuber - Nature 514, 68–71 (02 October 2014) doi:10.1038/nature13697 - Published online 01 October 2014

NASA Curiosity Rover: Long-lived rover sets off-world driving record

This natural colour view from NASA's Mars Exploration Rover Opportunity shows "Lunokhod Crater," which lies south of Solander Point on the west rim of Endeavour Crater. 

Credit: NASA/JPL-Caltech /Cornell /Arizona State Univ.

NASA's Opportunity Mars rover, which landed on the Red Planet in 2004, now holds the off-Earth roving distance record after accruing 25 miles (40 kilometers) of driving.

The previous record was held by the Soviet Union's Lunokhod 2 rover.

"Opportunity has driven farther than any other wheeled vehicle on another world," said Mars Exploration Rover Project Manager John Callas, of NASA's Jet Propulsion Laboratory in Pasadena, California.

"This is so remarkable considering Opportunity was intended to drive about one kilometer and was never designed for distance but what is really important is not how many miles the rover has racked up, but how much exploration and discovery we have accomplished over that distance."

A drive of 157 feet (48 meters) on July 27 put Opportunity's total odometry at 25.01 miles (40.25 kilometers).

This month's driving brought the rover southward along the western rim of Endeavour Crater.

The rover had driven more than 20 miles (32 kilometers) before arriving at Endeavour Crater in 2011, where it has examined outcrops on the crater's rim containing clay and sulfate-bearing minerals.

The sites are yielding evidence of ancient environments with less acidic water than those examined at Opportunity's landing site.

If the rover can continue to operate the distance of a marathon, 26.2 miles (about 42.2 kilometers), it will approach the next major investigation site mission scientists have dubbed "Marathon Valley."

Observations from spacecraft orbiting Mars suggest several clay minerals are exposed close together at this valley site, surrounded by steep slopes where the relationships among different layers may be evident.

The Russian Lunokhod 2 rover, a successor to the first Lunokhod mission in 1970, landed on Earth's moon on Jan. 15, 1973, where it drove about 24.2 miles (39 kilometers) in less than five months, according to calculations recently made using images from NASA's Lunar Reconnaissance Orbiter (LRO) cameras that reveal Lunokhod 2's tracks.

Irina Karachevtseva at Moscow State University of Geodesy and Cartography's Extraterrestrial Laboratory in Russia, Brad Jolliff of Washington University in St. Louis, Tim Parker of JPL, and others collaborated to verify the map-based methods for computing distances are comparable for Lunokhod-2 and Opportunity.

This chart illustrates comparisons among the distances driven by various wheeled vehicles on the surface of Earth's moon and Mars. 

Of the vehicles shown, the NASA Mars rovers Opportunity and Curiosity are still active and the totals for those two are distances driven as of May 15, 2013.

Credit: NASA/JPL-Caltech

"The Lunokhod missions still stand as two signature accomplishments of what I think of as the first golden age of planetary exploration, the 1960s and '70s," said Steve Squyres of Cornell University in Ithaca, New York, and principal investigator for NASA's twin Mars rovers, Opportunity and Spirit.

"We're in a second golden age now, and what we've tried to do on Mars with Spirit and Opportunity has been very much inspired by the accomplishments of the Lunokhod team on the moon so many years ago. It has been a real honour to follow in their historical wheel tracks."

As Opportunity neared the mileage record earlier this year, the rover team chose the name Lunokhod 2 for a crater about 20 feet (6 meters) in diameter on the outer slope of Endeavour's rim on Mars.

NASA LRO Images: Lunar Pits Could Shelter Astronauts

This video shows images from NASA's LRO spacecraft of various lunar pits. Since 2009, NASA's Lunar Reconnaissance Orbiter (LRO) has spotted hundreds of conspicuous holes on the Moon. 

These steep-walled "pits" might lead to underground environments sheltered from radiation, meteorite impacts, and extreme temperatures, making them valuable sites for future exploration.

This is a spectacular high-Sun view of the Mare Tranquillitatis pit crater revealing boulders on an otherwise smooth floor. 

This image from LRO's NAC is 400 meters (1,312 feet) wide, north is up. 

Image Credit: NASA /GSFC /Arizona State University.

While the moon's surface is battered by millions of craters, it also has over 200 holes; steep-walled pits that in some cases might lead to caves that future astronauts could explore and use for shelter, according to new observations from NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft.

The pits range in size from about 5 meters (~5 yards) across to more than 900 meters (~984 yards) in diameter, and three of them were first identified using images from the Japanese Kaguya spacecraft.

Hundreds more were found using a new computer algorithm that automatically scanned thousands of high-resolution images of the lunar surface from LRO's Narrow Angle Camera (NAC).

"Pits would be useful in a support role for human activity on the lunar surface," said Robert Wagner of Arizona State University, Tempe, Arizona.

"A habitat placed in a pit, ideally several dozen meters back under an overhang, would provide a very safe location for astronauts: no radiation, no micrometeorites, possibly very little dust, and no wild day-night temperature swings."

Wagner developed the computer algorithm, and is lead author of a paper on this research now available online in the journal Icarus.

Most pits were found either in large craters with impact melt ponds, areas of lava that formed from the heat of the impact and later solidified, or in the lunar maria, dark areas on the moon that are extensive solidified lava flows hundreds of miles across. In ancient times, the maria were thought to be oceans; "maria" is the Latin word for "seas."

Various cultures have interpreted the patterns formed by the maria features in different ways; for example, some saw the face of a man, while others saw a rabbit or a boy carrying a bundle of sticks on his back.

These images from NASA's LRO spacecraft show all of the known mare pits and highland pits. Each image is 222 meters (about 728 feet) wide.

Image Credit: NASA /GSFC /Arizona State University

The pits could form when the roof of a void or cave collapses, perhaps from the vibrations generated by a nearby meteorite impact, according to Wagner.

However, he noted that from their appearance in the LRO photos alone, there is little evidence to point to any particular cause.

The voids could be created when molten rock flowed under the lunar surface; on Earth, lava tubes form when magma flows beneath a solidified crust and later drains away.

The same process could happen on the moon, especially in a large impact crater, the interior of which can take hundreds of thousands of years to cool, according to Wagner.

After an impact crater forms, the sides slump under lunar gravity, pushing up the crater's floor and perhaps causing magma to flow under the surface, forming voids in places where it drains away.

Exploring impact melt pits would pin down the nature of the voids in which they form. "They are likely due to melt flow within the pond from uplift after the surface has solidified, but before the interior has cooled," said Wagner.

"Exploring impact melt pits would help determine the magnitude of this uplift, and the amount of melt flow after the pond is in place."

Exploring the pits could also reveal how oceans of lava formed the lunar maria.

"The mare pits in particular would be very useful for understanding how the lunar maria formed. We've taken images from orbit looking at the walls of these pits, which show that they cut through dozens of layers, confirming that the maria formed from lots of thin flows, rather than a few big ones."

"Ground-level exploration could determine the ages of these layers, and might even find solar wind particles that were trapped in the lunar surface billions of years ago," said Wagner.

To date, the team has found over 200 pits spread across the melt ponds of 29 craters, which are considered geologically young "Copernican" craters at less than a billion years old; eight pits in the lunar maria, three of which were previously known from images from the Japanese Kaguya orbiter; and two pits in highlands terrain.

The general age sequence matches well with the pit distributions, according to Wagner.

"Impact melt ponds of Copernican craters are some of the younger terrains on the moon, and while the maria are much older at around three billion years old, they are still younger and less battered than the highlands."

"It's possible that there's a 'sweet spot' age for pits, where enough impacts have occurred to create a lot of pits, but not enough to destroy them," said Wagner.

NASA LRO: Wet or Dry Moon

The Moon's status as a "dry" rock in space has long been questioned. Competing theories abound as to the source of the H20 in the lunar soil, including delivery of water to the Moon by comets.

This week, Tartèse et al announced in Geology that new analyses of lunar soil samples demonstrates that basalts from the Moon's mantle contain hydrogen from water indigenous to Earth.

According to the authors, their work is "challenging the paradigm of a "dry" Moon, and arguing that some portions of the lunar interior are as wet as some regions of the Earth's mantle."


This video from NASA Goddard shows how NASA’s Lunar Reconnaissance Orbiter (LRO) is helping scientists understand where water is likely to exist on the south pole of the Moon. 

Credit: NASA Goddard on YouTube

Since the 1960's, scientists have suspected that frozen water could survive in cold, dark craters at the Moon's poles.

While previous lunar missions have detected hints of water on the Moon, new data from the Lunar Reconnaissance Orbiter (LRO) pinpoints areas near the south pole where water is likely to exist.

The key to this discovery is hydrogen, the main ingredient in water: LRO uses its Lunar Exploration Neutron Detector (LEND), to measure how much hydrogen is trapped within the lunar soil.

By combining years of LEND data, scientists see mounting evidence of hydrogen-rich areas near the Moon's south pole, strongly suggesting the presence of frozen water.

More information: Romain Tartèse, Mahesh Anand, Francis M. McCubbin, Stephen M. Elardo, Charles K. Shearer, and Ian A. Franchi. "Apatites in lunar KREEP basalts: The missing link to understanding the H isotope systematics of the Moon." Geology, G35288.1, first published on February 25, 2014, DOI: 10.1130/G35288.1

NASA LRO: Interactive mosaic of the Moon's North Pole

A new interactive mosaic from NASA's Lunar Reconnaissance Orbiter (LRO) covers the north pole of the moon from 60 to 90 degrees north latitude at a resolution of 6-1/2 feet (2 meters) per pixel. 

Close-ups of Thales crater (right side) zoom in to reveal increasing levels of detail. 

Credit: NASA /GSFC /Arizona State University

Scientists, using cameras aboard NASA's Lunar Reconnaissance Orbiter (LRO), have created the largest high resolution mosaic of our moon's north polar region.

The six-and-a-half feet (two-meters)-per-pixel images cover an area equal to more than one-quarter of the United States.

Web viewers can zoom in and out, and pan around an area.

Constructed from 10,581 pictures, the mosaic provides enough detail to see textures and subtle shading of the lunar terrain.

Consistent lighting throughout the images makes it easy to compare different regions.

"This unique image is a tremendous resource for scientists and the public alike," said John Keller, LRO project scientist at NASA's Goddard Space Flight Center, Greenbelt, Md.

"It's the latest example of the exciting insights and data products LRO has been providing for nearly five years."

The images making up the mosaic were taken by the two LRO Narrow Angle Cameras, which are part of the instrument suite known as the Lunar Reconnaissance Orbiter Camera (LROC).

The cameras can record a tremendous dynamic range of lit and shadowed areas.

"Creation of this giant mosaic took four years and a huge team effort across the LRO project," said Mark Robinson, principal investigator for the LROC at Arizona State University in Tempe.

"We now have a nearly uniform map to unravel key science questions and find the best landing spots for future exploration."

The entire image measures 931,070 pixels square – nearly 867 billion pixels total.

A complete printout at 300 dots per inch – considered crisp resolution for printed publications, would require a square sheet of paper wider than a professional U.S. football field and almost as long.

If the complete mosaic were processed as a single file, it would require approximately 3.3 terabytes of storage space.

Instead, the processed mosaic was divided into millions of small, compressed files, making it manageable for users to view and navigate around the image using a web browser.

LRO entered lunar orbit in June 2009 equipped with seven instrument suites to map the surface, probe the radiation environment, investigate water and key mineral resources, and gather geological clues about the moon's evolution.

Researchers used additional information about the moon's topography from LRO's Lunar Orbiter Laser Altimeter, as well as gravity information from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission, to assemble the mosaic.

NASA LRO Searches Lunar Landscape for Lost Moon Probes

The moon is the final resting ground for scads of landed and crashed spacecraft, many of which have been pinpointed recently by sleuthing scientists.

Using observations by NASA's Lunar Reconnaissance Orbiter, for example, researchers have located and imaged Apollo moon landing leftovers, old Soviet-era spacecraft and, more recently, the impact locales of NASA’s twin Grail spacecraft that were deliberately driven into a mountain near the moon’s north pole.

But the search is ongoing to find the exact location of several pioneering moon landers.

"We are still looking for [the Soviet Union’s] Luna 9 and 13," said Jeff Plescia, a space scientist at the The Johns Hopkins University’s Applied Physics Laboratory in Laurel, Md.

"Those were the small 'beach ball' shaped spacecraft," Plescia told reporters "The beach ball might be hard to find, but it made a descent on a larger vehicle which then popped the beach ball off."

Plescia said he had assumed that it would be possible to find the landing sites of Luna 9 and 13 by spotting albedo marks — a change in the lunar surface brightness made by their descent engines.

Plescia is joined in the hunt by Mark Robinson of Arizona State University, principal investigator for the Lunar Reconnaissance Orbiter Camera, or LROC.

"We’ve both looked, but no luck so far." Plescia said.

Yet another search involves the impact sites of Apollo lunar module ascent stages, hardware discarded once moonwalking crews were snug within their respective command modules.

Ascent stages were intentionally impacted into the surface as part of the Apollo Passive Seismic Experiment that studied the propagation of seismic waves through the moon to yield a detailed look at the body's internal structure.

"Given that we have found the impact sites from Grail, you would think we could find those craters, but, again, no luck so far," Plescia said.

These, like the craters made by the third stage of NASA's Saturn V moon rocket, "are important to locate to understand how large a crater was made and to have precise coordinates so that the old Apollo era crustal velocity measurements can be reanalyzed," he said.

NASA LRO: Metamorphosis of moon's water ice explained

Panoramic lunar view taken by the Lunar Reconnaissance Orbiter Camera of the north rim of Cabeus crater. 

The distance from left to right is about 75 kilometers (46 miles). 

Image courtesy of NASA/GSFC/Arizona State Univ.

Using data gathered by NASA's Lunar Reconnaissance Orbiter (LRO) mission, scientists believe they have solved a mystery from one of the solar system's coldest regions—a permanently shadowed crater on the moon.

They have explained how energetic particles penetrating lunar soil can create molecular hydrogen from water ice.

The finding provides insight into how radiation can change the chemistry of water ice throughout the solar system.

Space scientists from the University of New Hampshire and NASA's Goddard Space Flight Center have published their results online in the Journal of Geophysical Research (JGR): Planets.

Lead author of the paper is research scientist Andrew Jordan of the University of New Hampshire's Institute for the Study of Earth, Oceans, and Space (EOS).

Discovering molecular hydrogen on the moon was a surprise result from NASA's Lunar Crater Observation Sensing Satellite (LCROSS) mission, which crash-landed the LCROSS satellite's spent Centaur rocket at 5,600 miles per hour into the Cabeus crater in the permanently shadowed region of the moon. 

These regions have never been exposed to sunlight and have remained at temperatures near absolute zero for billions of years, thus preserving the pristine nature of the lunar soil, or regolith.

Instruments on board LCROSS trained on the resulting immense debris plume detected water vapor and water ice, the mission's hoped-for quarry, while LRO, already in orbit around the moon, saw molecular hydrogen—a surprise.

"LRO's Lyman Alpha Mapping Project (LAMP), detected the signature of molecular hydrogen, which was unexpected and unexplained," says Jordan.

Jordan's JGR paper, "The formation of molecular hydrogen from water ice in the lunar regolith by energetic charged particles," quantifies an explanation of how molecular hydrogen, which is comprised of two hydrogen atoms and denoted chemically as H2, may be created below the moon's surface.

"After the finding, there were a couple of ideas for how molecular hydrogen could be formed but none of them seemed to work for the conditions in the crater or with the rocket impact." Jordan says.

"Our analysis shows that the galactic cosmic rays, which are charged particles energetic enough to penetrate below the lunar surface, can dissociate the water, H2O, into H2 through various potential pathways."

That analysis was based on data gathered by the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument aboard the LRO spacecraft.

Jordan is a member of the CRaTER scientific team, which is headed up by principal investigator Nathan Schwadron of EOS.

Schwadron, a co-author on the JGR paper, was the first to suggest energetic particles as the possible mechanism for creating molecular hydrogen.

CRaTER characterises the global lunar radiation environment by measuring radiation dose rates from galactic cosmic rays and solar energetic particles.

Says Jordan, "We used the CRaTER measurements to get a handle on how much molecular hydrogen has been formed from the water ice via charged particles."

Jordan's computer model incorporated the CRaTER data and showed that these energetic particles can form between 10 and 100 percent of the H2 measured by LAMP.

The study notes that narrowing down that percent range requires particle accelerator experiments on water ice to more accurately gauge the number of chemical reactions that result per unit of energy deposited by cosmic rays and solar energetic particles.

NASA SDO Image: The Moon and Sun

Two or three times a year, NASA’s Solar Dynamics Observatory observes the moon traveling across the sun, blocking its view. 

While this obscures solar observations for a short while, it offers the chance for an interesting view of the shadow of the moon. 

The moon’s crisp horizon can be seen up against the sun, because the moon does not have an atmosphere. 

NB: At other times of the year, when Earth blocks SDO’s view, the Earth’s horizon looks fuzzy due to its atmosphere.

If one looks closely at such a crisp border, the features of the moon’s topography are visible, as is the case in this image from Oct. 7, 2010. 

This recently inspired two NASA visualizers to overlay a 3-dimensional model of the moon based on data from NASA’s Lunar Reconnaissance Orbiter (LRO), into the shadow of the SDO image. 

Scott Wiessinger

Such a task is fairly tricky, as the visualizers — Scott Wiessinger who typically works with the SDO imagery and Ernie Wright who works with the LRO imagery -- had to precisely match up data from the correct time and viewpoint for the two separate instruments. 

Ernie Wright

The end result is an awe-inspiring image of the sun and the moon.

Image Credit: NASA/SDO/LRO/GSFC

NASA GRAIL Mission: LRO's LAMP Captures Lunar Impact

These models show the time evolution for hydrogen (left) and mercury (right) as plumes of gas rapidly expand into the vacuum of space following the planned impact of the GRAIL twins onto the lunar surface. 

Data from the Lyman-Alpha Mapping Project (LAMP) aboard NASA’s Lunar Reconnaissance Orbiter accurately constrain such models used to understand the impact event. 

Credit: JHUAPL/SwRI/NASA

When NASA's twin GRAIL spacecraft made their final descent for impact onto the Moon's surface last December, the Lunar Reconnaissance Orbiter's sophisticated payload was in position to observe the effects.

As plumes of gas rose from the impacts, the Lyman Alpha Mapping Project (LAMP) aboard LRO detected the presence of mercury and hydrogen and measured their time evolution as the gas rapidly expanded into the vacuum of space at near-escape velocities.

NASA intentionally crashed the GRAIL twins onto the Moon on Dec. 17, 2012, following successful prime and extended science missions.

Both spacecraft hit a mountain near the lunar north pole, which was shrouded in shadow at the time.

Developed by Southwest Research Institute (SwRI), LAMP uses a novel method to peer into the darkness of the Moon's permanently shadowed regions, making it ideal for observations of the Moon's night-side and its tenuous atmospheric constituents.

Dr. Kurt Retherford

"While our results are still very new, our thinking is that the hydrogen detected from the GRAIL site might be related to an enhancement at the poles caused by hydrogen species migrating toward the colder polar regions," says Dr. Kurt Retherford, LAMP principal investigator and a principal scientist at SwRI.

"Combining GRAIL results with LCROSS results could tell us more about hydrogen and water near the poles," says Dr. Thomas Greathouse, a LAMP team member and SwRI senior research scientist.

“We have begun to understand that the amount of water ice near the polar regions is higher than was previously thought, but we don't fully understand how it gets there."

LAMP usually observes the night-side lunar surface using light from nearby space (and stars), which bathes all bodies in space in a soft glow.

This Lyman-alpha glow is invisible to human eyes but visible to LAMP as it reflects off the Moon.

However, the new detection of Lyman-alpha emissions from native lunar atomic hydrogen gas released by the impact is a first for LAMP, and for any previous instrument.

NASA Grail Twin Probes Final Flight Path

The NASA GRAIL twin probes' final flight path into their crash site, imaged with data from NASA's Lunar Reconnaissance Orbiter (LRO). 

Credit: NASA/JPL-Caltech/GSFC/ASU

Two space probes that successfully mapped variations in the Moon's gravity field have been deliberately crashed into the lunar surface in a dramatic end to their mission.

They are just the latest in a string of probes to leave their shattered remains on the Moon. The impacts of the GRAIL probes, Ebb and Flow, into a 2.4 km high (1.5 miles) mountain near the lunar north pole, was deliberate and planned in great detail.

NASA decided to destroy the craft in a controlled manoeuvre rather than take the risk, however tiny, that they might later hit one of the historic landing sites of Apollo and unmanned probes.

The two spacecraft, each the size of a washing machine, fired their thrusters one last time to burn up the last of their fuel. They dropped into a lower orbit and hit the peak's southern face, near a crater called Goldschmidt, at 6,050 kph (3,760 mph).

NASA LRO Finds Further Evidence of Water On The Moon

Scientists from NASA and Boston University have found small patches of ice in the Shackleton Crater, at the south pole of the Moon.

Five to 10 percent of the crater wall is made of ice, they said, after analyzing data obtained from the Mini-RF radar on Nasa's Lunar Reconnaissance Orbiter.

"These terrific results from the Mini-RF team contribute to the evolving story of water on the moon. Several of the instruments on LRO have made unique contributions to this story, but only the radar penetrates beneath the surface to look for signatures of blocky ice deposits," said John Keller, a scientist at NASA's Goddard Space Flight Center.

Scientists believe that because the interior of the Shackleton crater lies in permanent shadow it is cold enough for ice to accumulate.

"Inside the crater, we don't see evidence for glaciers like on earth. Glacial ice has a whopping radar signal, and these measurements reveal a much weaker signal consistent with rugged terrain and limited ice," said Bradley Thomson, researcher at Boston University.

Lunar Reconnaissance Orbiter spectrometer detects helium in Moon's atmosphere

The Lyman Alpha Mapping Project (LAMP) aboard LRO (shown here in a pre-flight photo) uses a novel method to peer into the perpetual darkness of the moon's so-called permanently shadowed regions.

LAMP "sees" the lunar surface using the ultraviolet light from nearby space and stars, which bathes all bodies in space in a soft glow of ultraviolet light. (Credit: NASA Goddard/Debbie McCallum)

Geophysical Research Letters, Vol. 39, doi:10.1029/2012GL051797 , 2012.

Scientists using the Lyman Alpha Mapping Project (LAMP) aboard NASA's Lunar Reconnaissance Orbiter have made the first spectroscopic observations of the noble gas helium in the tenuous atmosphere surrounding the Moon.

These remote-sensing observations complement in-situ measurements taken in 1972 by the Lunar Atmosphere Composition Experiment (LACE) deployed by Apollo 17.

Although LAMP was designed to map the lunar surface, the team expanded its science investigation to examine the far ultraviolet emissions visible in the tenuous atmosphere above the lunar surface, detecting helium over a campaign spanning more than 50 orbits.

Because helium also resides in the interplanetary background, several techniques were applied to remove signal contributions from the background helium and determine the amount of helium native to the Moon.

Geophysical Research Letters published a paper on this research in 2012. "The question now becomes, does the helium originate from inside the Moon, for example, due to radioactive decay in rocks, or from an exterior source, such as the solar wind?" says Dr. Alan Stern, LAMP principal investigator and associate vice president of the Space Science and Engineering Division at Southwest Research Institute.

With support from LRO's suite of instruments, LAMP has previously determined that hydrogen, mercury and other volatile substances are present in the permanently shaded regions (PSRs) of the moon.

It has also observed PSRs are darker at far-ultraviolet wavelengths and redder than nearby surfaces that receive sunlight.

These darker regions indicate "fluffy" soils, while the reddening is consistent with the presence of water frost.

In a related study led by Dr. Paul Feldman of Johns Hopkins University and published in Icarus, observations showed day-to-day variations in helium abundances, possibly varying with the solar wind, and also significantly decreasing when the Moon passed behind Earth out of sight from the solar wind.

"If we find the solar wind is responsible, that will teach us a lot about how the same process works in other airless bodies," says Stern.

 If spacecraft observations show no such correlation, radioactive decay or other internal lunar processes could be producing helium that diffuses from the interior or that releases during lunar quakes.

A Tour of the Moon (Narrated) - YouTube

"Tour of the Moon" takes viewers to several interesting locations on the moon. Tour stops included in this breathtaking journey across the moon's surface are: Orientale Basin, Shackleton crater, South Pole-Aitken Basin, Tycho crater, Aristarchus Plateau, Mare Serenitatis, Compton-Belkovich volcano, Jackson crater and Tsiolkovsky crater.

NASA - Two New NASA LRO Videos: See Moon's Evolution, Take a Tour

"Evolution of the Moon" explains why the moon did not always look like it does now.

The moon likely started as a giant ball of magma formed from the remains of a collision by a Mars sized object with the Earth about four and a half billion years ago.

After the magma cooled, the moon's crust formed. Then between 4.5 and 4.3 billion years ago, a giant object hit near the moon's South Pole, forming the South Pole-Aitken Basin, one of the two largest proven impact basins in the solar system.

This marked the beginning of collisions that would cause large scale changes to the moon's surface, such as the formation of large basins.

Because the moon had not entirely cooled on the inside, magma began to seep through cracks caused by impacts. Around one billion years ago, it's thought that volcanic activity ended on the near side of the moon as the last of the large impacts made their mark on the surface.

The moon continued to be battered by smaller impacts. Some of the best-known impacts from this period include the Tycho, Copernicus, and Aristarchus craters.

So, while the moon today may seem to be an unchanging world, its appearance is the result of billions of years of violent activity.

The two-and-a-half minute video is available for viewing and downloading at: http://svs.gsfc.nasa.gov/goto?10930

 "Tour of the Moon" takes viewers to several interesting locations on the moon. Tour stops included in this breathtaking journey across the moon's surface are: Orientale Basin, Shackleton crater, South Pole-Aitken Basin, Tycho crater, Aristarchus Plateau, Mare Serenitatis, Compton-Belkovich volcano, Jackson crater and Tsiolkovsky crater.

The fully narrated video, as well as clips from each of the stops on the tour, are available to everyone in formats viewable on virtually any device.

To view the whole tour; go to: http://svs.gsfc.nasa.gov/goto?10929

iPad owners are also encouraged to download the NASA Viz app to see this and other NASA science stories updated twice a week. The story featuring Evolution of the Moon will be available Thursday, March 15.

To download the app, go to: http://svs.gsfc.nasa.gov/nasaviz/index.html

NASA Lunar Recon (LRO): Sharpest Ever Moon Map

NASA's Lunar Reconnaissance Orbiter (LRO) science team has released the highest resolution near-global topographic map of the Moon ever created.

Though the Moon is the Earth's closest neighbour, yet knowledge of its morphology is still limited.

"Due to the limitations of previous missions, a global map of the Moon's topography at high resolution has not existed until now," said NASA while releasing the map.

LRO's Wide Angle Camera and the Lunar Orbiter Laser Altimeter instrument will help scientists portray the shape of the entire Moon at high resolution accurately.

Check out below the new topographic map that shows the Moon's surface shape and features with a pixel scale close to 328 feet.

NASA: The Moon's North Pole

The Earth's moon has been an endless source of fascination for humanity for thousands of years.

When at last Apollo 11 landed on the moon's surface in 1969, the crew found a desolate, lifeless orb, but one which still fascinates scientist and non-scientist alike.

This image of the moon's north polar region was taken by the Lunar Reconnaissance Orbiter Camera, or LROC.

One of the primary scientific objectives of LROC is to identify regions of permanent shadow and near-permanent illumination.

Since the start of the mission, LROC has acquired thousands of Wide Angle Camera images approaching the north pole.

From these images, scientists produced this mosaic, which is composed of 983 images taken over a one month period during northern summer.

This mosaic shows the pole when it is best illuminated, regions that are in shadow are candidates for permanent shadow.

Image Credit: NASA/GSFC/Arizona State University

NASA LRO Images Offer Sharper Views of Apollo Landing Sites

NASA's Lunar Reconnaissance Orbiter (LRO) captured the sharpest images ever taken from space of the Apollo 12, 14 and 17 landing sites.

Images show the twists and turns of the paths made when the astronauts explored the lunar surface.

At the Apollo 17 site, the tracks laid down by the lunar rover are clearly visible, along with the last foot trails left on the moon. The images also show where the astronauts placed some of the scientific instruments that provided the first insight into the moon's environment and interior.

"We can retrace the astronauts' steps with greater clarity to see where they took lunar samples," said Noah Petro, a lunar geologist at NASA's Goddard Space Flight Center in Greenbelt, Md., who is a member of the LRO project science team.

All three images show distinct trails left in the moon's thin soil when the astronauts exited the lunar modules and explored on foot. In the Apollo 17 image, the foot trails, including the last path made on the moon by humans, are easily distinguished from the dual tracks left by the lunar rover, which remains parked east of the lander.

"The new low-altitude Narrow Angle Camera images sharpen our view of the moon's surface," said Arizona State University researcher Mark Robinson, principal investigator for the Lunar Reconnaissance Orbiter Camera (LROC). "A great example is the sharpness of the rover tracks at the Apollo 17 site. In previous images the rover tracks were visible, but now they are sharp parallel lines on the surface."

http://www.nasa.gov/mission_pages/LRO/news/apollo-sites.html

Did the Earth Have Two Moons?

A paper just published in the journal Nature speculates that our home planet may have just one lonely moon now, but long ago, like Mars and Sylvia, we had two.

"Whether it's right or not, I don't know," says Maria Zuber, a planetary scientist at MIT who wrote an opinion piece accompanying the new study. "But I think it's very plausible."

The idea, cooked up by astronomers Martin Jutzi and Erik Asphaug, of the University of California at Santa Cruz, started out as an attempt to explain why our moon has so asymmetrical a surface.

The part that faces us is relatively smooth, with vast expanses of ancient lava forming flat, dark, low-lying plains that earlier astronomers mistook for oceans but when space probes first circled the moon in the early 1960s, scientists learned that the far side is mostly covered with rugged mountains and craters.

Nobody has ever been able to explain with certainty why the moon should be so lopsided: maybe it had to do with some kind of massive impact that violently rearranged the surface, much like what happened to the asteroid Vesta.

Maybe it was a slightly off-center core that caused the crust to be thinner on the Earth-facing half of the moon, which made that hemisphere more susceptible to lava bleeds.

But then Jutzi and Asphaug began thinking. "It looked to us a little bit as though the highlands on the far side accreted" — which is to say, they were added on top of the pre-existing surface.

The astronomers thought a bit more, and realized that this idea was consistent with scientists' beliefs about how the moon formed in the first place. Thanks to the analysis of moon rocks that were brought back by the Apollo missions, planetary scientists are pretty sure that our satellite was born billions of years ago when a Mars-size planetoid smashed into the young Earth.

The impact blasted off a cloud of debris from both of the objects and sent it spinning into space, where it eventually congealed into the moon. There could have been other, smaller pieces as well, says Zuber, but their orbits would have been unstable, causing them either to be flung away or to fall into Earth or the moon pretty much immediately.

Except, that is, if they happened to end up at a Trojan point — a place in the same orbit as the moon, but either well ahead of or well behind it, that's gravitationally stable — or relatively so anyway. Just last week, astronomers announced the discovery of a Trojan asteroid leading the planet Earth around the sun. There's no reason a Trojan moon couldn't lead or follow our moon around the Earth.

After a few tens of millions of years, Moon Jr. would become unstable, almost certainly falling into Moon Sr. But Jutzi and Asphaug's computer simulations of how that would play out showed that the short-lived satellite would have fallen surprisingly gently, at only a few miles per second, making more of a splat than a bang.

At a more typical impact speed, which would be at least 10 times faster, says Zuber, "you'd make a big hole and fling off ejecta" — in short form, a massive crater.

In this case, you'd form just a pile of extra stuff on one side, as though you slapped a handful of mud onto a basketball. And if the minimoon were about 750 miles (1,200 km) across, with about a third as much mass as its big brother, it could account for most of the extra material we now see on the far side.

The scenario could also explain why the near side is paved over with so much lava. At the time of impact, the moon would have cooled from its original molten state to form a thin crust, with an ocean of magma underneath.

All the extra mass added to the far side could have squeezed most of the subsurface magma around to the side that faces us, providing an ample supply of molten rock for later eruptions. "Every once in a while I read a paper I really enjoy," says Zuber.

"This is a genuinely new idea. That's what really struck me."

A new theory in science isn't worth much, however, unless you can test it somehow. The best way would be to look for the mineralogical signature of such an event in rocks brought back from the far side of the moon.

Unfortunately, no such mission is in the works anytime soon. But the Lunar Reconnaissance Orbiter, or LRO, which is circling the moon even now, has detectors that can get at least a sense of the minerals below.

And in September, another moon probe will be on its way, with Zuber as principal investigator. It's called GRAIL, for Gravity Recovery and Interior Laboratory.

Actually, it's a pair of probes that will orbit in tandem; changes in the distance between them will measure the local lunar gravity with extraordinary precision.

That will give Zuber and her team a detailed look at the moon's geological (or technically, selenological) structure and history, and when combined with LRO's data, could make or break Jutzi and Asphaug's idea.

LRO Images Lunar Farside In Stunning Detail

Because the moon is tidally locked (meaning the same side always faces Earth), it was not until 1959 that the farside was first imaged by the Soviet Luna 3 spacecraft (hence the Russian names for prominent farside features, such as Mare Moscoviense).

And what a surprise - unlike the widespread maria on the nearside, basaltic volcanism was restricted to a relatively few, smaller regions on the farside, and the battered highlands crust dominated. A different world from what we saw from Earth.

Of course, the cause of the farside/nearside asymmetry is an interesting scientific question. Past studies have shown that the crust on the farside is thicker, likely making it more difficult for magmas to erupt on the surface, limiting the amount of farside mare basalts.

Why is the farside crust thicker? That is still up for debate, and in fact several presentations at this week's Lunar and Planetary Science Conference attempt to answer this question.

The Clementine mission obtained beautiful mosaics with the sun high in the sky (low phase angles), but did not have the opportunity to observe the farside at sun angles favorable for seeing surface topography.

This WAC mosaic provides the most complete look at the morphology of the farside to date, and will provide a valuable resource for the scientific community. And it's simply a spectacular sight!

The Lunar Reconnaissance Orbiter Camera (LROC) Wide Angle Camera (WAC) is a push-frame camera that captures seven color bands (321, 360, 415, 566, 604, 643, and 689 nm) with a 57-km swath (105-km swath in monochrome mode) from a 50 km orbit.

One of the primary objectives of LROC is to provide a global 100 m/pixel monochrome (643 nm) base map with incidence angles between 55 degrees -70 degrees at the equator, lighting that is favorable for morphological interpretations.

Each month, the WAC provides nearly complete coverage of the Moon under unique lighting. As an added bonus, the orbit-to-orbit image overlap provides stereo coverage.

Reducing all these stereo images into a global topographic map is a big job, and is being led by LROC Team Members from the German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt; DLR).

NASA LRO: Unprecedented Topographic Map Of Moon

NASA's Lunar Reconnaissance Orbiter is allowing researchers to create the most precise and complete map to date of the moon's complex, heavily cratered landscape.

"This dataset is being used to make digital elevation and terrain maps that will be a fundamental reference for future scientific and human exploration missions to the moon," said Dr. Gregory Neumann of NASA's Goddard Space Flight Center in Greenbelt, Md.

"After about one year taking data, we already have nearly 3 billion data points from the Lunar Orbiter Laser Altimeter on board the LRO spacecraft, with near-uniform longitudinal coverage.

We expect to continue to make measurements at this rate through the next two years of the science phase of the mission and beyond.

Near the poles, we expect to provide near-GPS-like navigational capability as coverage is denser due to the spacecraft's polar orbit."

Neumann will present the map at the American Geophysical Union meeting in San Francisco December 17.
The Lunar Orbiter Laser Altimeter (LOLA) works by propagating a single laser pulse through a Diffractive
Optical Element that splits it into five beams.

These beams then strike and are backscattered from the lunar surface. From the return pulse, the LOLA electronics determines the time of flight which, accounting for the speed of light, provides a precise measurement of the range from the spacecraft to the lunar surface.


NASA's LRO Creating Unprecedented Topographic Map Of Moon