Saturday, July 31, 2010

Water cycle on the Moon remains a mystery

Schematic showing a daily cycle of hydration, loss and rehydration on the lunar surface. [University of Maryland/McREL].

Nancy Atkinson
Universe Today

"Water cycle on the Moon" is a phrase that many people – including lunar scientists – were never expecting to hear. This surprising new finding of ubiquitous water on the surface of the Moon, revealed and confirmed by three different spacecraft last year, has been one of the main topics of recent discussion and study by lunar researchers. But figuring out the cycle of how water appears and disappears over the lunar day remains elusive. As of now, scientists suspect a few different processes that could be delivering water and hydroxyl (OH) to the lunar surface: meteorites or comets hitting the Moon, outgassing from the Moon's interior, or the solar wind interacting with the lunar regolith. But so far, none of the details of any of these processes are adding up.

"When we do the model, we assume the way that the water is lost is through photodissociation, and so that sets the timescale," Hurley told Universe Today. "And using that timescale the amount that is coming in through the solar wind or micrometeorites can't add up to the amount observed if it is in steady state, so something is not jiving."

Dana Hurley from The Johns Hopkins University Applied Physics Laboratory is part of team of scientists attempting to model the lunar water cycle, and she discussed the work at the NASA Lunar Science Institute's third annual Lunar Forum at Ames Research Center, July 20-22, 2010.

(Heads up to Lunar Mark)
Read the full article, HERE.

See Also: The Four Flavors of Lunar Water
Dr. Paul D. Spudis

Friday, July 30, 2010


THEMIS P1 (TH-B) in red and P2 (TH-C) orbit between the beginning of it reconfiguration and October 2010 when after capturing the Lagrange points between Earth and Moon. After six months in those orbits, P1 and P2 will be inserted into lunar orbits where they should make measurements of the lunar wake, the magnetotail and the solar wind through September 2012 [NASA/GSFC/UC/THEMIS].

Irene Klotz
Aviation Week

Two satellites of NASA’s five-member Themis constellation, launched in February 2007 to study geomagnetic storms, are approaching lunar orbit for a new mission called Artemis.

NASA has yet to authorize funding for Artemis (Acceleration Reconnection and Turbulence and Electrodynamics of the Moon’s Interaction with the Sun), but there was no time to wait. Left in their previous orbits, the satellites would have fallen into prolonged periods of deep shadow that likely would have resulted in their demise.

“We started thinking of different methods for saving them – even before they were launched,” says Themis principal investigator Vassilis Angelopoulos, with the University of California at Berkeley. “We realized that if we had enough fuel to change their orbits, the Moon’s gravity would start pulling them up.”

With preliminary approval from NASA’s 2008 Heliophysics Senior Review Panel, the two outermost Themis probes began low-thrust lunar orbit insertion maneuvers on July 20, 2009. The first will reach a preliminary orbit in August, with the second to follow in October. The recycled spacecraft will become the first identical duo to study the Moon and its environment.

From their new vantage points in front of and behind the Moon, relative to the Sun, the satellites will continue to support the Themis (Time History of Events and Macroscale Interactions During Substorms) mission with collaborative studies, but their main focus will be on solar wind and lunar environmental research. The new initiatives, slated to begin in April, include studying solar wind turbulence and charged-particle acceleration; looking at how reconnection releases solar energy stored in the Earth’s magnetotail; probing the cavity created when solar wind blows around the Moon; determining the composition of the lunar surface by studying particles that have been blown off the surface into space; looking for structure in the surface magnetic field of the Moon; assessing the Moon’s internal structure by measuring how it impacts magnetic fields in space; and measuring electric fields near the Moon, which levitate dust and send it into space.

“We’d like to work with other existing and forthcoming missions too,” says Themis project scientist David Sibeck at NASA’s Goddard Space Flight Center in Greenbelt, Md. “We could provide information about the radiation environment of the Moon, and we could provide information about the environment while they study the local details.”

The satellites would remain in lunar orbit for 18 months. At the end of the Artemis mission, the spacecraft would be maneuvered into a controlled crash onto the lunar surface.

“We hope that the science will be exciting enough to warrant additional funding … It’s really peanuts compared to what it would cost for new spacecraft,” Angelopoulos said.

The Themis team has ideas for follow-on missions for the remaining probes as well. “The others have enough fuel to do other very useful things, such as combining them with future missions like MMS [Magnetospheric Multiscale Mission, scheduled to launch in 2014]. We keep reinventing ourselves,” Angelopoulos says.

Read the 2008 Mission study (pdf), HERE.

Acceleration, Reconnection Turbulence, and Electrodynamics of Moon's Interaction with the Sun (ARTEMIS), with its full complement of charged particle, magnetic and electric field, and wave measurements, can provide multi-point measurements of the wake over a wide range of downstream distances for varying solar wind conditions and to address the wide array of phenomena that occur in the lunar wake. The newly reassigned probes will spend four days per month, from October 2010 to September 2012, in the magnetotail. P1 and P2 will observe the plasma sheet from 20 to 30 hours per month, each collecting 2400hrs of magnetotail data, including 500-700hrs in the plasma sheet; more than enough to characterize this region of space and define its variability at unprecedented time resolution (burst mode) and with well inter-calibrated instrumentation. From vantage points spanning kinetic to global phenomena, ARTEMIS will revolutionize our understanding of particle acceleration, the nature and effects of reconnection and the drivers and effects of turbulence in Earth’s distant magnetotail [NASA/GSFC/UC/THEMIS].

State's Moon rock rescued from oblivion

North Carolina State University professor Christopher Brown holds North Carolina's long-neglected Apollo 17 lunar sample [Charlotte Observer].

Jay Price
Charlotte Observer

It is the hardest proof of a peak of human achievement, far rarer than any gem and maybe worth $5 million or more.

It's also a drab little black pebble encased in a plastic ball and glued to a slightly kitschy early 1970s plaque. Which might help explain how the state's official moon rock ended up in a desk drawer at the Department of Commerce, then spent the past seven years in the custody of an N.C. State University professor who took it on occasional visits to school groups.

No longer. On Tuesday, the professor, Christopher Brown, brought the rock and other artifacts that it came with to the state Museum of Natural Sciences, where it is expected to go on display in a major new wing called the Nature Research Center when it opens in the fall of 2011.

"I've shown it to, who knows, hundreds of people," Brown told museum officials after handing over the rock. "You'll show it to thousands every day."

Joseph Gutheinz, a retired NASA investigator who since 2002 has led an informal project to locate the 370 or so lunar samples given to the states and other countries, said he was overjoyed to hear that North Carolina's had surfaced. But, he added, the museum needs to be careful.

A host of moon rocks have been stolen, from NASA itself in several cases, and a few have apparently traded hands for millions of dollars.

Some are now displayed under bulletproof glass with video cameras trained on them and guards nearby, said Gutheinz, a Houston lawyer who teaches classes in investigative techniques at the University of Phoenix. Over the years, he has assigned about 1,000 students to help locate the rocks.

"When people know where this moon rock is, it will become a target," Gutheinz said. "You want it on display, you want it shown. But if they don't create a secure display, it's like a bundle of money just sitting out there, and someone will make a play for it."

Read the full article, HERE.

Thursday, July 29, 2010

A molten flood

A flood of impact melt swept away from the rim of Necho crater (5°N, 123.1°E). LROC Narrow Angle Camera observation M119041553, LRO orbit 2676, January 25, 2010; resolution 0.56 m/p, above field of view = 540 meters (see full image HERE) [NASA/GSFC/Arizona State University].

Brett Denevi
LROC News System

Large impacts are catastrophic events for the local area. Besides the huge craters they leave behind (this one is 30 km or 19 miles across), impacts heat portions of the crust to such high temperatures that rocks melt and flow like lava, as seen in today's featured image. These melts run downhill, cool and solidify, leaving behind beautiful flow features also highlighted in several past featured images.

A reduced resolution view of the impact melt outside the eastern rim of Necho, from a mosaic of M119041553L/R; field of view = 5.3 km [NASA/GSFC/Arizona State University].

The scene above is a wider view outside the eastern rim of Necho crater (the detailed view in the first image is in the upper left corner here). Almost everything you see is coated in impact melt, which flowed from the crater, moving boulders along with it and ponding in small topographic lows, which now look like smooth, frozen lakes. What a sight this must have been shortly after the crater formed!

A Wide Angle Camera (WAC) monochrome view of 30km Necho. The impact melt is concentrated outside the northeastern rim, approximate location of the NAC detailed views is indicated by arrow. Image M119048299M [NASA/GSFC/Arizona State University].

Impact melts play a key role in our understanding of when things happened on the Moon. As rock is melted and then cools and reforms, its internal radiometric clock is reset. By collecting a sample of impact melt scientists can very accurately determine when that crater formed. Since crater rays run out long distances we can determine the relative ages of rays, material that underlies rays, and rays that cross other rays. By sampling a few key craters scientists could easily unravel the absolute chronology of some key events on the Moon over the past billion years - a time not well sampled during the Apollo years. Sample return missions are a high priority for lunar exploration, and absolute age dating is only one of the many reasons why!

How many impact melt features can you see in the full NAC image of Necho?

From Lunar Pioneer 4

Wednesday, July 28, 2010

Not your average complex crater

The small, irregular terraces on the walls of Bürg Crater and the debris piles and outcropping wall material, with strong variations in reflectance, only hint at the geologic diversity of this complex crater. Bürg's rim is on the upper left, with downslope direction toward the lower right. Illumination is from the right, Full-sized image HERE, field of view = 870 meters (LROC NAC M116139887R, LRO orbit 2249, December 22, 2009; Altitude 41.33 km, resolution 0.65) [NASA/GSFC/Arizona State University].

Lillian Ostrach
LROC News System

Bürg crater, ~40 km in diameter, is located in Lacus Mortis and represents a fine example of a complex crater.

On the Moon, complex craters form above diameters of about 15 to 20 km. Unlike most simple craters (diameters less than 15 km), complex craters often show a wide range of morphologies and geologic features.

Overall, complex craters exhibit terraced walls, flat floors, and central peaks. However many factors, including bolide composition, bolide velocity, and target composition, influence the complex crater morphology - which is why we observe so many different complex crater varieties.

Subset of a map-projected LROC WAC monochrome context image of Bürg crater. Notice the terraced crater walls, the smooth crater floor, and the well-developed central peaks. The arrow points to the location of the area highlighted in the opening LROC NAC image [NASA/GSFC/Arizona State University].

Bürg crater is unique from many other complex craters because instead of having a broadly circular rim, the crater's rim is scalloped and wavy. Sometimes, pre-existing geologic structures or features help shape a crater during crater formation.

Meteor Crater on Earth has a slightly polygonal shape because of the joints and fractures that pervade the target sedimentary rocks. Could pre-existing joints in the mare basalts filling Lacus Mortis explain the scalloped nature of Bürg's rim? Possibly, but because the overall shape of the crater itself is circular and resembles other complex craters on the Moon, structural influences may have only affected portions of the crater rim, causing differential collapse and terrace formation.

Looking closely at the portion of the LROC WAC image above, there seems to be greater terracing and wall-slumping on the western side of the crater, which also happens to be less circular than the eastern rim. However, before we use this observation to interpret the origin for the scalloped crater rim, we need to look at additional LROC NAC images and the LROC WAC image in detail to substantiate this hypothesis.

Explore Bürg's rim for yourself to see what geologic clues you can find that provide insight into the geologic features of this beautiful complex crater!

LROC team identifies a new lunar crater

Updated 28 July 2010 2118 UT

A new natural impact crater, less than 38 years old, definitively identified on the Moon. This small crater is not visible in orbital metric mapping camera images photographed during the Apollo 15 mission, it formed sometime during the past 38 years. The new impact crater is only ~10 meters (30 feet) across, but its bright ejecta extends much farther, making it stand out from all the nearby craters. (LROC NAC observation M108971316L, LRO orbit 1193, Sept. 9, 2009; alt. 47.19 km, res. 0.5; field of view above is ~120 meters) [NASA/GSFC/Arizona State University].

Ingrid Daubar
LROC News System

By comparing photographs from past eras of lunar exploration with the high resolution data being returned by the Lunar Reconnaissance Orbiter Narrow Angle Camera, we can identify new craters that have formed in the last four decades. In this case, bright ejecta and rays extend from an impact site that is not present in the previous image from the Apollo 15 panoramic camera.

LROC Wide Angle Camera image M119584866M showing the approximate position, on the eastern side of Franz crater, part of the bright and rugged Palus Somni region on the Moon's Near Side, of the LROC Narrow Angle Camera observation (M108971316L) from which today's Featured Image was sampled. View the full-sized Wide Angle Camera image, HERE [NASA/GSFC/Arizona State University].

The Apollo 15 image (AS15-P-9527) was taken in August 1971 with the sun 64° above the horizon. The LROC WAC image (M108971316L) was taken in September 2009 when the sun was 72° above the horizon. Images taken under similar lighting conditions like these are the most useful for identifying and comparing surface features.

Comparisons by the LROC Science Team of images from the Apollo Panoramic Camera and the LROC Narrow Angle Camera will reveal impact craters that have formed within the past 38 years. View the full sized comparison, HERE. [NASA/GSFC/Arizona State University].

Using these two images as "before" and "after" views, we can conclude that a natural object (asteroid or comet) about 0.5 m (~20 inches) in diameter must have impacted the Moon here within the last 38 years. Note that this location (16.92° N latitude, 40.50° E longitude) does not correspond to a known impact site for any spacecraft.

The impact exposed fresh material from underneath the surface. Rays of this bright material extend far outward from the central crater, helping us to clearly identify it. The rays are actually more than 3x more reflective than the underlying basalts! Thus, even though the crater itself is only ~10 meters (30 feet) across, the bright markings would have been prominent in the high-sun Apollo image if the crater had existed in 1971.

Discoveries of recent, datable impact craters like these establish the present-day impact cratering rate on the Moon, which will lead to better understanding of the bombardment rate in the inner solar system. Meteorites of this size are a potential hazard to future explorers on the Moon or anywhere in the inner Solar System where there is no shielding atmosphere.

If we have a better sense of the current impact rate for this size of impactor, we can more effectively design habitats and hardware to protect human explorers. A crater this young has also not been modified by other processes, so we can study the appearance of features we know are extremely fresh. In addition, since ages are estimated using the number of craters present on planetary surfaces, knowing how many and how often craters are currently being produced will improve our understanding of the history of the entire Solar System.

Browse the whole Narrow Angle Camera frame HERE. Charles Wood, archivist of the Lunar Picture of the Day forum (LPOD) has added some personal notes about these discoveries, HERE.

One of five new impact craters (right) discovered by the LROC team at Arizona State by comparing Apollo J mission orbital mapping photography with Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) observations now being gathered four decades later. It's shown in "three dimensions" superimposed onto the digital elevation model (DEM) available to users of the Google Earth application. The bright and much larger impact crater on the left is about thirty meters higher in elevation, less than a kilometer to the southeast. Much further away to south the LROC NAC Observation M108971316 runs north over the rim and into the eastern interior of Franz crater, a landmark of the distinctive Palus Somni. Aspects of the immediate landscape perhaps affected by the impact and its subsequent shock wave that are perhaps visible in the two dimensional strip (below) imaged 41 km overhead may be better understood in the context of the uneven elevation.

Is the Moon really 'Been there, done that?'

Like Viking settlements in Maritime Canada abandoned centuries before Columbus, forty years after the Apollo era six lunar module descent stages stand lonely near the foot prints where twelve Americans became the first to scratch the lunar surface. Now as then, there are those who question the value of exploring the Moon. The unquestioned scientific value of those earlier excursions was eclipsed by their geopolitical triumph. But, in the early years of the 21st century we have discovered better reasons for returning to the Moon than during the century prior to Apollo. The Moon appears to be an essential key to Deep Space, to our understanding the history of the Solar System, and no understanding of Earth can hope to be complete before a proper exploration of Earth's Moon.

Nancy Atkinson
Universe Today

If there's only one thing we've learned from all the highly successful recent Moon missions – the Lunar Reconnaissance Orbiter, LCROSS, Chandrayaan-1 and Kaguya — it's that the Moon is perplexingly different from our perceptions of the past 40 years. The discovery of water and volatiles across the surface and in the permanently shadowed regions at the poles changes so many of the notions we've had about Earth's constant companion. Basically, just within the past year we've realized the Moon is not a dry, barren, boring place, but a wetter, richer and more interesting destination than we ever imagined. And so, the proposal for NASA to effectively turn away from any human missions to the Moon, as well as Administrator Charlie Bolden's 'been there, done that' comments is quite perplexing – especially for the lunar scientists who have been making these discoveries.

"It's been quite a year for the Moon," said Clive Neal, a lunar geologist from Notre Dame, speaking last week at the NASA Lunar Science Institute's annual Lunar Forum at Ames Research Center. "And things got quite depressing around February 2010."

That's when President Obama proposed a new budget that effectively would end the Constellation program and a return to the Moon.

At the Forum, lunar scientists shared their most recent findings – as well as their attempts to model and comprehend all the data that is not yet understood. But they saved any discussion of NASA's future until the final presentation of the meeting.

"Hopefully this talk will stop you from running out of here ready to hang yourself or slit your wrists," quipped Neal, who led the final session.

The week began, however, with keynote speaker Andrew Chaikin – author of the Apollo 'bible,' "A Man on the Moon," and several other space-related books — saying, "We have to erase that horrendous 'been there done that' notion." Chaikin also shared a famous Peanuts cartoon showing Lucy pulling the football out from under from Charlie Brown. No caption was needed for everyone to understand to what Chaikin was referring.

"With all of these new discoveries, we should have ample reason to believe that humans will follow," said Chaikin. But right now, he added, the man in the Moon looks a little like Rodney Dangerfield. "The Moon wants – and deserves – respect."

Read the article, HERE.

Monday, July 26, 2010

The Moon, Asteroids, and Space Resources

Totality at Shackleton - In Situ Resource Utilization (ISRU), high on everyone's list of essential learning curves ahead of growing permanent human presence beyond the cradle of Earth points us inevitably to our natural Deep Space Port and harbor, only 1.5 light-seconds away.

Paul D. Spudis
The Once & Future Moon
Smithsonian Air & Space

By abandoning the Moon, the administration’s proposed space policy has left the space community with a huge question mark over the important issue of learning how to harvest and use space resources. Clearly if we don’t go to the Moon with people or machines, there is no way to use the abundant water, metals, and other lunar surface materials to create new capabilities in space. Supporters of the new path suggest instead that we can obtain all the materials we want from near-Earth asteroids, small, rock-like objects that co-orbit the Sun with the Earth. Indeed, some asteroid types appear to contain significant quantities of water, thus offering a possibly rich source of off-planet water.

Water is an extremely useful substance in space. By virtue of its varied utility, water enables extended human presence in space. Besides its obvious role as a sustaining substance for human life (both drinking and providing oxygen for breathing), water is also an excellent material to shield from cosmic radiation and a medium of energy storage, both by thermal storage and also through its use in rechargeable fuel cells, where hydrogen and oxygen are combined at night (producing water and electricity). Stored water is disassociated by solar generated electricity during the day and re-stored as hydrogen and oxygen. Most importantly, water can be converted into liquid hydrogen and liquid oxygen; in this form, it is the most powerful chemical rocket propellant known.

So what are the relative benefits and drawbacks of using asteroidal (not lunar) resources? The biggest advantage of asteroids is that they have extremely low surface gravity. As these objects are simply very large rocks, they don’t have much mass and hence, virtually no surface gravity. A mission to an asteroid is more akin to a rendezvous in space than it is to a planetary landing. The advantage this confers is that vehicles can come and go to a given asteroid without the requirement to expend large amounts of propellant in a landing, with total changes in velocity measured in the few meters to tens of meters per second range. In contrast, a landing on the Moon requires a propulsive burn of over 2200 meters per second, both coming and going. This deep “gravity well” penalty is much smaller than launching from Earth (11,000 meters per second), but is still substantial compared with “dimple” dimensions of asteroid gravity wells.

The asteroids have much to offer for material resources and we will eventually journey to and use many of them. But we have business on the Moon first. Mining the unlimited wealth of the Solar System will become inevitable once we have learned the lessons of how to do this job on our nearest neighbor.
If the propulsive energy of access were the only (or even the main) consideration for resource exploitation, asteroids would win hands down. But there are some other issues to consider. Water is indeed present in the materials of Near-Earth asteroids, but in a chemically bound form. Water molecules fill sites in the crystal structures in rock-forming minerals, bound strongly to its encasing structure. These chemical bonds must be broken to extract the water and that takes energy. On the Moon, water occurs in bound form, but also in its native state as ice in the lunar polar regions. Ice-laden dirt can be scooped up and minimally heated to extract the water. In contrast, it takes 100 to 1000 times more energy to extract a kilogram of water from chemically bound asteroidal minerals than it does to scoop up the “free water” found in the lunar cold traps. The greater quantity of energy needed to extract water from an asteroid is annoying, but can be handled through the use of large solar arrays or even a nuclear reactor to generate copious amounts of electrical power. But both solutions bring significant mass penalties and a nuclear reactor significantly increases cost, both from the technical development it would require and from the hurdles raised by legal and environmental groups it would have to overcome.

A more critical issue is the location of the two resource bodies. The proximity of the Moon is a major boon for its utilization. The Moon is both close and accessible. In terms of closeness, it takes 3 seconds for a radio signal traveling at the speed of light to go the Moon and back. This makes the remote, telepresence operation of lunar robots from Earth feasible. Early steps in the location, surveying and harvesting of demonstration amounts of resources on the Moon can be done remotely with robots controlled from Earth. We do not have this luxury with asteroids.

Asteroids orbit the Sun (like the Earth does) and vary in distance from Earth by tens of millions of miles over the course of a year. At best, asteroids are several tens of light-seconds away and at times, tens of light-minutes. This long radio time-lag means that direct remote operation of robots on asteroids will be cumbersome, if not impossible. For well understood routine tasks, this may not be a serious issue, but space resource utilization is something we have yet to learn. It is unclear whether we will be able to harvest and process asteroid water using remote robots, but it is almost certainly possible to do so with robots on the Moon.

The other aspect of the Moon’s proximity is accessibility, the ability to access a space destination routinely and often. As the Moon orbits the Earth, we can go to and come back from the Moon pretty much at will – launch windows are almost always open. In contrast, because even near-Earth asteroids follow their own paths around the Sun, launch windows are short and come at irregular (albeit predictable) intervals. Round trips to and from asteroids are even more difficult and after multiple weeks to months of travel, loiter times are either very short (on the order of a week or so) or very long (a year or more). This wildly variable duration of access may be handled on a robotic mission, but it precludes any significant human/robot interaction during the materials processing on an asteroid.

Finally, there is the issue of surface gravity. Much of the “dirty work” of resource processing involves separating some substance from another, or extracting something embedded. Having gravity usually makes this an almost trivial step, one that we don’t think about very much – unless we don’t have it. The Moon does indeed have a significant gravity well (about 1/6 that of the Earth) and although this works against us when we want to export product, it works in our favor when we need to process materials. The extremely weak surface gravity of an asteroid is almost microgravity and makes it very difficult to separate materials there without specialized equipment, again adding mass, power, complexity and cost to the processing chain.

In short, there are many considerations to take into account when planning an architecture based on resource exploitation. The seemingly damning case against going to the Moon to harvest material resources largely revolves around its relatively high surface gravity. It takes roughly two tons of water-equivalent liquid hydrogen-liquid oxygen propellant to lift one ton of water to the L1 point, where it can be used to supply and fuel a variety of spacecraft destined for many different places. That same ton of water lifted from the Earth would take over 19 tons of propellant to deliver it. The other side of that coin is that gravity is extremely useful – if not critical – for many materials processing techniques. Gravity can only be artificially created near an asteroid at some expense and mission complexity, whereas on the Moon, it’s a feature that comes for free.

Learning how to access and use space resources is a critical skill for a space faring society – skills and knowledge that will reap rewards right here on Earth. The Moon offers us a school and a laboratory for acquiring this critical knowledge. By virtue of its proximity, accessibility and resource endowments, the Moon satisfies our early space ISRU needs and allows us to create new capabilities to routinely access cislunar space, where all of our economic and national security space assets reside. The asteroids have much to offer for material resources and we will eventually journey to and use many of them. But we have business on the Moon first. Mining the unlimited wealth of the Solar System will become inevitable once we have learned the lessons of how to do this job on our nearest neighbor.

Come and Get It! - Apollo 12 lunar module pilot Alan Bean in what's become one of the iconic Apollo lunar surface mission photographs (Astronomy Picture of the Day, January 21, 2006). Cmdr. Pete Conrad snaps his partner's picture moments after scooping a sampling of extremely course and fine lunar regolith into a bottle designed to seal and retain its native vacuum. All such bottles failed, consistent with the stubborn nature of submicron-sized lunar grains. All that's needed to build and supply future missions beyond the Moon, space stations and orbital fuel depots are now known to exist in situ, on the Moon. Just as no study of Earth can ever be complete without a proper study of the Moon, neither will our understanding of the Solar System. And exploring, studying and eventually living on Mars, the asteroids and all points beyond will ultimately come about because of our Moon, not despite it [AS12-49-7278 - Pete Conrad/NASA/ASU].

LRO's Diviner continues to map lunar terrain

Thermal data gathered during repeated orbital passes using LRO's Diviner shows the range of materials of similar composition in and around 109 million year-old Tycho, putting the familiar crater in a new light, including the distinctive twin ray trails [NASA/GSFC/UCLA/UW].

Eric Hand
Nature: The Great Beyond

Scientists are using temperature measurements to map the rockiest parts of the Moon – and the results could help NASA choose better landing sites for missions.

Infrared radiation readings taken by the Diviner Lunar Radiometer Experiment, an instrument on NASA’s Lunar Reconnaissance Orbiter (LRO) mission, have enabled researchers to see the moon’s temperature variations in detail. Not surprisingly, the surface heats up during the day and cools down at night. But rocks tend to retain their heat longer than the regolith, or lunar soil, and so they stay warm throughout the night.

Mapping these hot spots has provided a quick and quantitative way to assess rock abundance over vast areas of the Moon, says planetary scientist Josh Bandfield of the University of Washington in Seattle, who presented his results on Thursday at the Third Annual NASA Lunar Science Forum, held at NASA Ames Research Center at Moffett Field, California.

Because rocks get worn away over time, older craters tend to be less rocky. But a young crater like Tycho “just lights up” on the rock abundance map, says Bandfield (see image).

The Diviner team has also mapped spots that are cold enough to retain water ice. Around the Moon’s south pole, the surfaces of crater floors fulfill this criteria – but there are even larger surrounding areas where water ice would be stable below the surface, said planetary scientist David Paige of the University of California, Los Angeles at the forum. These regions might warm up during the hottest part of the year, but the subsurface would stay cool enough to preserve water ice for billions of years, he said.

China's Long March engine plans justified by manned Moon program

China's Long March 5 heavy-lift, as modeled for a recent exhibition. Power profiles for secondary stage engines now being tested exceed requirements for geostationary orbit. China's missile marketers claim the extra power can justified by a manned lunar landing program.

Anatoly Zak

According to Li Tongyu, general manager of the marketing department at the China Academy of Launch Vehicle Technology (CALT), engineers are currently studying a rocket engine capable of generating thrust of 600 tonnes.

If China succeeds in the development of such power, it would increase the nation's capabilities in space by orders of magnitude.

For comparison, China is currently well in the development of its most powerful rocket to date - Long March-5 - that would sport engines with the thrust of 120 tonnes.

"Rockets (with 600-tonne thrust engines) would only be justified for things like sending humans to the Moon, if such projects are approved," Li Tongyu told BBC News.

Read the article, HERE.

Sunday, July 25, 2010

Lunar meteoroid impact observations and the flux of kilogram-sized meteoroids

Probable Leonid Impact, November 17, 2006

Rob Suggs,
Marshall Space Flight Center

The Lunar Impact Monitoring team at Marshall Space Flight Center continues a coordinated program of observations. Monitoring the flux of kilogram-sized meteoroids has helped determine population indexes for some meteor showers.

The measured flux of meteoroids in the 100 gm to 1 kg range remains consistent with other observations. The observing program has significantly increased the number of lunar impacts observed, over 200 impacts have been recorded in 4 years.

This presentation (PDF) reports on 115 impacts taken "under photometric conditions" during the first 3 full years of operation.

The Lunar Impact Monitoring team plans to continue for the foreseeable future: 1) Running detailed models to help explain an observed concentration near the Moon's trailing limb 2) Building up statistics to better understand meteor shower dynamics 3) Providing support in the planning future seismometers (ILN) and LADEE, and 4) Deploying near-infrared and visible cameras with dichroic beamsplitters to the Half Meter Telescope in New Mexico.

Peak Flash Magnitude - 108 impacts over 212 hours observing time used in this study continues to show a clear Flux Asymmetry – 1.55 x 10-7 evening (left) 1.07x10-7 morning (#/km2/hr) Lunar meteoroid impact observations and the flux of kilogram-sized meteoroids, Suggs,, NASA MSFC, May 12, 2010 [NASA/MSFC].

Meteoroids 2010, Breckenridge, CO, 24-28 May 2010

Yvonne Pendleton new NLSI director at Ames

David Perlman
San Francisco Chronicle

Dr. Yvonne Pendleton
New NLSI director

Yvonne Pendleton, a pioneer astrophysicist at NASA's Ames Research Center in Mountain View, has been named director of the center's Lunar Science Institute, the space agency announced.

The institute leads teams of scientists both at Ames and across the nation and abroad whose research focuses on the moons of Earth and other planets of the solar system. Pendleton succeeds planetary scientist David Morrison, who has led the institute for three years and is an expert on asteroids whose paths carry them toward possible impacts on Earth.

Pendleton and her husband, Ames research astronomer Dale P. Cruikshank, are among a group of scientists whose discoveries of life's precursor chemicals in the icy hearts of comets have given rise to current theories on the origin of life on Earth. Those ideas hold that Earth's life - and possibly life on Mars, too - arose from the organic chemicals that those comets carried here from the most distant reaches of the solar system billions of years ago.

During her 31-year career as a NASA researcher, Pendleton has also served as chief of the Ames Space Science and Astrobiology Division.

Morrison was recently appointed director of the Carl Sagan Center for the Study of Life in the Universe at the independent SETI Institute in Mountain View. He will continue part time as senior scientist at the lunar research institute.

Pendleton's new appointment was announced Monday, the day before the third annual Lunar Science Forum at Ames.

Saturday, July 24, 2010

The colorful Moon

Following up on Dr. Mark Robinson's LROC Featured Image, "Aristarchus - Up from the Depths," from July 20 presented the opportunity to add some color to create a value-added product. Above, at its heart, is a new three-dimensional glimpse north from high over the southern rim of the dazzling and brilliant Copernican-age crater Aristarchus, possible by superposition of LROC Narrow-Angle Camera (NAC) observation M122523410 onto a low-resolution digital elevation model of Aristarchus Plateau available through the Google Earth application. A touch of color has been added, previously available only to the most diligent operators of telescopes, Clementine data and, most recently, LRO's fast-developing Wide Angle Camera catalog. The ultimate potential of such recombinations boggle the mind.

From 2008, a 200 kilometer-wide (at bottom) SELENE-1 (Kaguya) HDTV view of Aristarchus Plateau, very close to it's true optical appearance from orbit. Subtleties of actual color variation are difficult to detect, though they are definitely present [JAXA/NHK/SELENE].

Aristarchus (July 25, 2008, 02:33UT) composed by "The Boys from Minsk," aka Astronominsk (Goryachko, Abgarian & Morozov), who were not the first to demonstrate the availability of color in lunar photography, even from 400,000 km away. This image of Aristarchus was featured by Charles Wood as Lunar Picture of the Day (LPOD), August 5, 2008. [Maksutov-Cassegrain Santel (D=230mm, F=3000mm), barlow 2x, CCD mono camera Unibrain-702 (1388x1040), Astronomik RGB TYP II filters. "Seeing" = 6/10, Trans 5/5].

Special G. K. Gilbert Award Session for Carle Pieters at Geological Society of America

Each year the Planetary Geology Division of the Geological Society of America, responding to peer nominations, presents the G.K. Gilbert Award to a planetary scientist in recognition of outstanding contributions to the solution of fundamental problems in planetary geology through the use of geochemistry, mineralogy, petrology, geophysics, geologic mapping, and/or remote sensing. The Gilbert Award is the highest honor the Division can bestow.

This year's Gilbert Award will be presented to Dr. Carle M. Pieters for her pioneering work in remote sensing of planetary surfaces and crusts.

The award is named for G. K. Gilbert, who 100 years ago clearly recognized the importance of a planetary perspective in solving terrestrial geologic problems. The G. K. Gilbert Award is presented annually for outstanding contributions to the solution of fundamental problems in planetary geology in the broadest sense, which includes geochemistry, mineralogy, petrology, geophysics, geologic mapping, and remote sensing. Such contributions may consist either of a single outstanding publication or a series of publications that have had great influence in the field.

Presentation of the G. K. Gilbert Award is made during the annual business meeting of the Division held in association with the Annual Meeting of the Society.

Head's Up to Dr. Clive Neal

Friday, July 23, 2010

A Dark Cascade at Sulpicius Gallus

LROC Narrow Angle Camera (NAC) close-up of the wall of a suspected volcanic vent within the regional pyroclastic deposit near Sulpicius Gallus (19.69°N, 10.27°E). From LROC NAC Observation M124505982R (LRO orbit 3482, March 29, 2010), view is approximately 2 km in width. [NASA/GSFC/Arizona State University].

Lisa Gaddis
LROC News System

Although there are hundreds of sites on the Moon where explosive volcanism has occurred, there are several regional deposits of pyroclastic material that are especially extensive. These regional pyroclastic deposits include sites at Rima Bode, Sinus Aestuum, Mare Vaporum, and Sulpicius Gallus, and are collectively called "dark spots" because of their very dark appearance in telescopic images.

All of the regional pyroclastic deposits have largely rock-free surfaces that are thought to have large concentrations of micron-sized glass and partially crystalline spheres, similar to the glassy materials sampled by Apollo 17 astronauts at Taurus-Littrow Valley. These deposits likely formed in explosive eruptions (or "fire fountains") involving magma and some kind of volatile component. Both carbon monoxide and water have been considered as the source of the gas that drives such explosive eruptions on the Moon.

LROC Wide Angle Camera (WAC) monochrome mosaic of the Sulpicius Gallus region along the southwestern interior of Mare Serenitatis. The suspected volcanic vent is at the center of the Constellation Region of Interest delineated by the white box. Rima Sulpicius Gallus cuts through the area immediately to the north and a number of domes are also visible. (NOTE: Charles Wood, curator of the invaluable Lunar Picture of the Day (LPOD) website, provides detailed and experienced insight into this latest LROC WAC image HERE.)[NASA/GSFC/Arizona State University].

Where are the volcanic vents that were the sources of these widespread pyroclastic deposits?

Source vents for many of the larger pyroclastic deposits are difficult to identify, partly because they may have been mantled during explosive eruptions and/or buried by later volcanic material. In some cases, fractures, oddly shaped craters, or irregular depressions have been suggested as possible source vents. Such is the case for at least some of the pyroclastic material in the Sulpicius Gallus region, a Constellation Region of Interest, where a 5.5-km long "kidney-shaped depression" is considered a prime candidate for a volcanic vent.

This irregular depression was first noted by the crew of Apollo 17 as they looked down at the Moon from orbit. The fact that it lacked the prototypical features of an impact crater (raised rim, bowl shape) and that its walls and surroundings had an orange/red color similar to the orange pyroclastic glasses that were sampled at the Apollo 17 landing site made it quite distinct from the typical impact crater.

The LROC Narrow Angle Camera view of the wall of this suspected volcanic vent is similar to what the Apollo 17 crew would have seen from in orbit, albeit at higher resolution and in black and white (we rely on the LROC Wide Angle Camera for color).

In this image, the dark pyroclastic mantle at the surface has mixed with rubble and soil from the mare surface to create a small landslide or debris flow (~60 m wide) that has flowed down the wall onto the floor below. Several smaller flows can been seen and more coherent rocky layers are also observed at intervals within the wall, probably representing buried mare basalt layers.

The pyroclastic beads at sites such as Sulpicius Gallus are of high interest to lunar scientists for several reasons. They contain trapped hydrogen and Helium-3 from the solar wind, and these materials could be of high value for future in-situ energy production on the Moon. Enrichment of volatile elements such as sulfur and fluorine also have been measured on the surfaces of many of the pyroclastic beads in the Apollo sample collection, suggesting that these beads could provide lunar inhabitants with sources for these relatively rare elements. Finally, the glassy deposits are also rich in iron and titanium, which are of immense economic and engineering value to future lunar explorers.

Scroll through the full-resolution NAC frame here!

Thursday, July 22, 2010

Chang’e I research reported published

An extra sharp high-altitude photograph of Rima Sharp, at the 'narrows' junction of Oceanus Procellarum and Mare Frigoris (46.7°N, 349.5°E) swept up by Chang'e-1 (2008), China's first lunar orbiter [CNSA].

NLSI (Staff) - The scientific research achievements of China’s circumlunar satellite Chang’e I have now been published, China National Radio’s website reports.

Ouyang Ziyuan, chief scientist of the lunar exploration program, disclosed that 1.37TB of data was captured by Chang’e 1 during its operation from October 24, 2007 to March 1, 2009. Following processing, analysis and study, 2.76TB of data products have been obtained.

The scientific research achievements include a full moon picture, a full moon digital elevation model and the 3D moon topographic map with high resolution and precision.

The satellite also captured data on the distribution of various chemical and mineral elements on the moon, the distribution of microwave radiation temperatures on the lunar surface and data of near-lunar space high-energy particles and solar ions.

Research work on Chang’e 1 also contributed to the preliminary establishment of the country’s standard system on moon exploration and scientific data processing, said Ouyang Ziyuan.

Early global lunar photomosaic of Chang'e-1 surveys, released by the Chinese National Space Agency [CNSA].

Don Wilhelms receives Shoemaker Award

Don Edward Wilhelms received the Shoemaker Distinguished Lunar Scientist Award last night during a ceremony of the Lunar Science Forum at NASA's Ames Research Center, Moffett Field, Calif. The award is given annually to a scientist who has significantly contributed to the field of lunar science.

Wilhelms was hired by Gene Shoemaker and worked at the United States Geological Survey (USGS), Menlo Park, Calif., as an astrogeologist for 24 years. He retired from the USGS in 1986.

His research was very broad, covering nearly all categories of lunar science. According to scientists, no student of the lunar surface, its terrain, and the geologic context of samples can function without the framework developed by Wilhelms.

"Dr. Wilhelms has literally written the book on lunar geology. Both of his books, 'To a Rocky Moon' and 'The Geologic History of the Moon,' have been required reading for students of lunar science," said David Morrison, retiring director of the Lunar Science Forum.

David King of the Lunar and Planetary Institute in Houston notes, "Wilhelms' real-time guidance to the Apollo program was extraordinary. Furthermore, his geologic analyses and interpretative maps continued to shape our measure of the Moon for decades after the Apollo era."

The Rima Hyginus region from the USGS Mare Vaporum Quadrangle, by Don Wilhelms {1968) [LPOD/moonzoo].

The first Distinguished Lunar Scientist Award was given posthumously last year to Gene Shoemaker and presented to his wife, Carolyn, for Shoemaker's many contributions to the lunar geological sciences.

Wednesday, July 21, 2010

Bhabha sinks into the shadows

Last rays striking central peaks of Bhabha, just before sunset. An oblique view from the west looking east; LROC observation M133982125, July 17, 2010 [NASA/GSFC/Arizina State University].

Mark Robinson
Principal Investigator
Lunar Reconnaissance Orbiter Camera (LROC)
Arizona State University

The central farside crater Bhabha (64 km diameter) was named in honor of the physicist Homi Jehangir Bhabha (1909-1966), a nuclear physics pioneer in his home country of India.

Bhabha Crater lies deep within the interior of the enormous South Pole-Aitken (SPA) Basin.

Full resolution close-up of the summit of Bhabha's central peaks [NASA/GSFC/Arizona State University].

Bhabha has a trio of central peaks that rise over a kilometer above the crater floor, and it has an intricate and complex system of rim terraces. Bhabha itself is a deep crater whose floor lies some 3 to 3.5 km below the crater rim. The crater is of special interest because the impact that formed it penetrated deep into the SPA Basin floor and excavated materials of the SPA Basin impact-melt complex, distributing these materials onto the surrounding plains.

Even though this event happened long ago in the Moon's history, those materials are still present in the surrounding plains deposits waiting for a lunar explorer - whether robotic or human - to come along and return them to Earth. These materials could then be used to address several important scientific questions, including age-dating the SPA Basin formation event, determining the nature of the materials that melted when SPA formed, and figuring out how deep the impact penetrated - perhaps through the lower crust and into the upper mantle of the Moon!

Bhabha is truly a window deep into the interior of the Moon and deep into the ancient history of the Solar System.

Full view across Bhabha crater [NASA/GSFC/Arizona State University].

Look at those boulders on the summit. They may contain some of the deepest materials readily available from the Moon's crust. Imagine collecting samples of these precious materials yourself and returning them to Earth!

Explore the full-resolution LROC
Narrow Angle Camera view of Bhabha

The Boulders of Bhabha [NASA/GSFC/Arizona State University].

Small steps, 41 years later

Still relatively pristine, the first tentative steps on another world are visible under a high sun in LROC Narrow Angle Camera observation M109080308RE, imaged last fall. Gardening by micrometeors, at the very least, may leave these first footfalls intact for the next 2 million years [NASA/GSFC/Arizona State University].

Tuesday, July 20, 2010

LROC: Aristarchus - Up from the Depths

Updated September 30, 2010, 1825 UT

700 meter wide LRO Narrow Angle Camera (LROC NAC) strip of the central peak of Aristarchus crater; NAC M122523410 [NASA/GSFC/Arizona State University].

Mark Robinson
Principal Investigator
Lunar Reconnaissance Orbiter Camera (LROC)
Arizona State University

Crater central peaks are formed as the Moon's crust rebounds after the tremendous stress of an impact is released. The energies of impacts are so high that rocks no longer behave as brittle solids, but rather as deformable plastic. It's more accurate to think of the crust behaving like a fluid - as the crater forms, the bottom of the crater is first pressed down, then it rebounds. For craters above 20 km in diameter, the rebound is so strong that material from depth is actually brought up and forms a central peak. In the case of Aristarchus crater, the central peak contains rocks with three very different albedos. As these materials erode out of the central peak they slide downslope, creating contrasting stripes. The highest albedo material reflects about four times as much light as the lowest albedo rocks.

Reduced resolution NAC mosaic of the Aristarchus central peak, opening image is centered in the upper middle of this view [NASA/GSFC/Arizona State University].

What causes these extreme differences in albedo? From other datasets (Earth based telescopes, Clementine, Chandrayaan, Kaguya) it has long been known that the interior of Aristarchus crater is compositionally heterogeneous. The high albedo material is most likely a common lunar rock type, anorthosite. The bulk of the lunar crust is made of anorthosite - it forms the bright material that you see when you look at the Moon (the dark areas are basaltic). On the other hand, perhaps we are seeing a more silicic rock akin to granite? Such silica-rich rocks are known to form on the Moon, we just do not know much about their origin and locations. What is the dark material in exposed in the Aristarchus central peak? Scientists are not sure, however we know the adjacent Aristarchus plateau is blanketed in dark pyroclastic deposits.

"Pyroclastic" derives from the Greek words for fire and broken, as in the small, hot broken rocks erupted in an explosive volcanic event. It is likely that the dark material is related to the nearby pyroclastics - perhaps the impact excavated a now solidified dike that once carried volcanic material to the surface.

LROC WAC images define distinct color differences in the ejecta of Aristarchus crater (40 km diameter). Clearly the impact event excavated a complex geology from beneath the surface -- a great target for future robotic and human exploration. WAC bands 689 nm, 566 nm, and 321 nm are displayed in red, green, and blue respectively. Arrow marks the central peak seen in the NAC image [NASA/GSFC/ Arizona State University].

To truly understand the geology of a location scientists typically examine the subsurface as well as the surface. On Earth geologists can drill holes, go into mines, and inspect road cuts. Planetary scientists must rely on impact craters to expose subsurface rocks - nature provides us with natural drill holes! The WAC color image dramatically shows regional differences, most likely due to changes in rock type. These colors are different than what your eye would see. First, the WAC is sensitive to ultraviolet wavelengths (300 to 400 nm) where some minerals (ilmenite for one) are highly absorptive, thus providing a marker of their presence, like a fingerprint. Secondly, images that contain subtle color differences can be stretched to bring out small variations. Mapping of color units that correspond to rock boundaries will guide future planners in terms of identifying the diversity of rock types. How do these broad color differences relate back to the boulders seen lying on the crater floor? Subtle color differences may not be readily apparent to the naked eye. Future explorers would want to carry portable color analyzers (spectrometers) to help sort through the boulders they will encounter on the surface.

Boulders of all sizes are eroding out of the peak and slowly working their way down slope; the large boulder indicated with the arrow is 35 meters across [NASA/GSFC/Arizona State University].

The clarity and details of the boulder shapes seen in NAC images are astonishing. Can you find any boulders that contain contacts (boundaries) of two rock units? Even without high resolution color, contacts can often be identified. Future astronauts exploring Aristarchus crater could easily sample materials from the highest point of the central peak without actually having to climb to the summit. They will simply browse the samples delivered to the base!

Two Constellation regions of interest are located in the Aristarchus area and were the subject of past featured images: learn more about the diverse geology of the Aristarchus Plateau and the pyroclastic deposits that blanket the region.

Supporting Narrow Angle Camera Observations:
M122523410L & M122523410R

Watch a flyover video!

Aristarchus Plateau proves the Moon is not so without color as many believe. Bright Aristarchus crater itself is a fresh and brilliant excavation of the region. It is not hard to see why its immediate vicinty is the site for most reports of "Transient Lunar Phenomena." The Plateau presents a changing face each month as the Moon waxes Full and the terminator gradually sweeps across Oceanus Procellarum, from the eastern heights, lit by sun well before the sunrise nearby to the complete, blinding and colorful full illumination [Goryachko, Abgarian & Morozov / Astronominsk].

Additional Reading:
The Great Wall of Aristarchus
September 30, 2010