Friday, October 29, 2010

Boulder trails in Menelaus crater

Boulder trails are common to the interior of Menelaus crater as materials erode from higher topography and roll toward the crater floor. Downhill is to the left, image height is 500 meters, from LROC Narrow Angle Camera observation M139802338L, LRO orbit 5736, October 9, 2010 [NASA/GSFC/Arizona State University].

Lillian Ostrach
LROC News System

Most boulder trails are relatively high reflectance, but running through this image is a lower reflectance trail. This trail is smaller than the others, and its features may be influenced by factors such as mass of the boulder, boulder speed as it traveled downhill, and elevation from which the boulder originated.

For example, is the boulder trail less distinct than the others because the boulder was smaller? What about the spacing of boulder tracks? The spacing of bounce-marks along boulder trails may say something about boulder mass and boulder speed. But why is this boulder trail low reflectance when all of the surrounding trails are higher reflectance? Perhaps this boulder trail is lower reflectance because the boulder gently bounced as it traveled downhill, and barely disturbed a thin layer of regolith? The contrast certainly appears similar to the astronauts' footprints and paths around the Apollo landing sites. Or, maybe the boulder fell apart during its downhill travel and the trail is simply made up of pieces of the boulder - we just don't know yet.

LROC WAC context of Menelaus crater at the boundary between Mare Serenitatis and the highlands (dotted line). The arrow marks the location of today's featured image at contact between the crater floor and NE crater wall [NASA/GSFC/Arizona State University].

What do you think? Why don't you follow the trail to its source in the full LROC NAC frame and see if you can find any other low reflectance trails.

Related posts:
Menelaus' distinctive rays
Small crater at the southern rim of Menelaus
Southern rim of Menelaus Crater
Hole in One!
Bright Boulder Trail
Bouncing, Bounding Boulders!

Southern rim of Menelaus crater

Perspective view HERE. The fresh crater featured previously
is barely visible further up the slope.

Rocks outcrop immediately within the rim of Menelaus and afterward roll downslope toward the crater floor as they erode out from the crater wall (to the upper right). (The boulder at top-middle is 8 meters across) Image (full-size available HERE) field of view is 400 meters, sampled from LROC Narrow Angle Camera observation M126826332L, LRO orbit 3824, April 25, 2010 [NASA/GSFC/Arizona State University].

LROC Wide Angle Camera mosaic of 27 km Menelaus and associated ejecta at the boundary between Serenitatis basin and the equatorial Near side highlands, deeply etched by the Imbrium basin-forming impact event. The arrow marks the location of today's featured image, just inside the crater's southern rim [NASA/GSFC/Arizona State University].

Traverse the rim of Menelaus crater in the full LROC NAC image!

-Lillian Ostrach

Thursday, October 28, 2010

Small crater at the southern rim of Menelaus

Updated October 28, 2010 - 1739 UT

Simulated view looking west from 26 km over the southern edge of Serenitatis basin at Menelaus, in context. The Narrow Angle Camera frames from which the LROC featured image was cropped can be seen as the long, slightly darker rectangular strip running north to south over Menelaus' western rim - see full-sized image HERE. The bright fresh crater can be seen on the crater's southwest rim. The contrast of terrains straddled by Menelaus is stark, between Serenitatis on the north and the highly grooved mountains on the south. Mare Tranquilliatis is at upper right. Rimae Menelaus marks the boundary of basalt melt fills, older and later partial inundation. Menelaus ejecta blanket stretches into (and over) the older Serenitatis fill - and an interior deeper (-4200 meter) than the basin's fill would seem to indicate Menelaus is younger than most features seen here [NASA/GSFC/Arizona State University - Google Earth (v.5.3)].

LROC Wide Angle Camera mosaic of Menelaus crater (16.3°N, 16.0°E), at the boundary between Mare Serenitatis and the highlands (dotted line). Broad ejecta rays extend along the mare-highland boundary and also in the NE-SW direction. In this image, the ejecta ray extending to the SW is easier to distinguish than the ray extending into Mare Serenitatis. The arrow marks the location of a recent 350 meter diameter impact near the rim of Menelaus. A full-sized view is HERE [NASA/GSFC/Arizona State University].

Lillian Ostrach
LROC News System

Menelaus crater (27 km diameter) straddles the highland-mare boundary at the southern margin of Mare Serenitatis. For years, scientists have wondered why Menelaus crater exhibits such a distinctive ray pattern. The distinctive ejecta pattern is partly a result of an oblique impact angle of the bolide that formed Menelaus. The ejecta rays are high reflectance relative to the surrounding terrain, but are these maturity or compositional rays? In most cases, a well-defined, high reflectance ray pattern suggests the relative youth of an impact crater. However, Menelaus crater formed in highland material, so Menelaus' rays may result more from compositional differences between the excavated material and the surrounding region, rather than the relative youth of the ejecta deposits. In fact, the optical maturity map for Menelaus crater, which is derived from Clementine multispectral data, supports this hypothesis because the crater rays are not visible, indicating that the rays are relatively mature (bright areas are immature).

Materials of different reflectance are exposed by a 350 meter diameter fresh impact crater near the southern rim of Menelaus (16.3°N, 16.0°E). The western wall of this small impact crater appears to be composed primarily of very high reflectance material. Image field of view is 400 meters, from LROC Narrow Angle Camera observation M126826332R, LRO orbit 3824, April 25, 2010 (Altitude 40.71 km, resolution 48 cm per pixel; illumination is from the right (west). A fill-size view is available HERE [NASA/GSFC/Arizona State University].

Small craters, like the one above, near larger craters (less than 1 kilometer in diameter) help scientists unravel questions about larger impact events. This small crater is visible in Apollo Metric images and also in the Clementine optical maturity map; in the maturity map, the crater is bright and thus the ejecta material is interpreted to be immature. We know that impacts into ejecta blankets sample the material excavated during crater formation, and this recent impact into Menelaus ejecta effectively exposes material, most likely of anorthositic composition that was brought up from the floor of Menelaus. Its reflectance is low because of its physical state (glassy), not because it is a different rock type.

So, what does this small crater tell us about Menelaus crater? Since the small crater exposes immature Menelaus ejecta, we know that the surface of Menelaus is mature and thus the Menalaus rays show up due to a compositional difference (highlands on mare) and not because of a maturity contrast. This small crater provides an excellent opportunity for future astronauts to study compositional and maturity rays at the same location!

Discover the ejecta patterns of this small crater for yourself in the full LROC NAC image!

Related posts:
Splendors of Mare Smythii
May 20, 2010
Rima Bode: Constellation Region of Interest
May 18, 2010
Small crater on the wall of Metius B
October 19, 2009
Ejecta sweeps the surface
October 11, 2009
Ejecta Blanket
September 23, 2009

LROC Featured Image in context, again, on the southwest rim of Menelaus, a crater that is itself on the southern tier of Serenitatis basin (the northern horizon - see full-sized image HERE). The range of elevations seen here, within the virtual environment of Google Earth's lunar digital elevation model, is dramatic. From overhead, there's little indication of the uneven height of Menelaus' rim, though its uneven height at upper left is close to the global average. Serenitatis basin (beyond the ejecta blanket of Menelaus, about thirty kilometers away) quickly levels out to en elevation gradually descending beginning at around -2,700 meters. But in the shadowed interior of Menelaus, about 10 km away, there are areas below -4200 meters. The featured image square is overlaid on the LROC NAC observation from which it was sampled which, in turn, is set within a regional WAC monochrome mosaic from many LRO observation opportunities [NASA/GSFC/Arizona State University - Google Earth (v.5.3)].

"Dead spacecraft walking"

Artist's concept of ARTEMIS A and B (formally THEMIS-P1 and P2), after a circuitous, low-energy orbital transfer resembling a year-long round of pin-ball - back and forth many times between Lagrange points, finally in lunar orbit on a new and important mission. (A full-sized view is available HERE.) Flight Dynamics data from ARTEMIS P2 recently indicated one electric field instrument end-effector may have been struck by a meteoroid [NASA/UCLA].

Tony Phillips

In 2007 NASA launched a fleet of five spacecraft into Earth's magnetosphere to study the physics of geomagnetic storms. Collectively, they were called THEMIS, short for "Time History of Events and Macroscale Interactions during Substorms." P1 and P2 were the outermost members of the quintet.

Working together, the probes quickly discovered a cornucopia of previously unknown phenomena such as colliding auroras, magnetic spacequakes, and plasma bullets shooting up and down Earth’s magnetic tail. This has allowed researchers to solve several longstanding mysteries of the Northern Lights.

The mission was going splendidly, except for one thing: Occasionally, P1 and P2 would pass through the shadow of Earth. The solar powered spacecraft were designed to go without sunlight for as much as three hours at a time, so a small amount of shadowing was no problem. But as the mission wore on, their orbits evolved and by 2009 the pair was spending as much as 8 hours a day in the dark.

"The two spacecraft were running out of power and freezing to death," says Angelopoulos. "We had to do something to save them."

The team brainstormed a solution. Because the mission had gone so well, the spacecraft still had an ample supply of fuel--enough to go to the Moon. "We could do some great science from lunar orbit," he says. NASA approved the trip and in late 2009, P1 and P2 headed away from the shadows of Earth.

With a new destination, the mission needed a new name. The team selected ARTEMIS, the Greek goddess of the Moon. It also stands for "Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon’s Interaction with the Sun."

The first big events of the ARTEMIS mission are underway now. On August 25, 2010, ARTEMIS-P1 reached the L2 Lagrange point on the far side of the Moon. Following close behind, ARTEMIS-P2 entered the opposite L1 Lagrange point on Oct. 22nd. Lagrange points are places where the gravity of Earth and Moon balance, creating a sort of gravitational parking spot for spacecraft.

The ARTEMIS spacecraft are currently located at the L1 and L2 Earth-Moon Lagrange points. ARTEMIS-P1 is the first spacecraft to navigate to and perform stationkeeping operations around the Earth-Moon L1 and L2 Lagrangian points. A full-size view is available HERE, and a YouTube demonstration of the route taken to the new mission can be seen HERE [NASA/GSFC/UCLA].

"We're exploring the Earth-Moon Lagrange points for the first time," says Manfred Bester, Mission Operations Manager from the University of California at Berkeley, where the mission is operated. "No other spacecraft have orbited there."

Because they lie just outside Earth's magnetosphere, Lagrange points are excellent places to study the solar wind. Sensors onboard the ARTEMIS probes will have in situ access to solar wind streams and storm clouds as they approach our planet—a possible boon to space weather forecasters. Moreover, working from opposite Lagrange points, the two spacecraft will be able to measure solar wind turbulence on scales never sampled by previous missions.

"ARTEMIS is going to give us a fundamental new understanding of the solar wind," predicts David Sibeck, ARTEMIS project scientist at the Goddard Space Flight Center. "And that's just for starters."

ARTEMIS will also explore the Moon's plasma wake—a turbulent cavity carved out of the solar wind by the Moon itself, akin to the wake just behind a speedboat. Sibeck says "this is a giant natural laboratory filled with a whole zoo of plasma waves waiting to be discovered and studied."

Another target of the ARTEMIS mission is Earth's magnetotail. Like a wind sock at a breezy airport, Earth's magnetic field is elongated by the action of the solar wind, forming a tail that stretches to the orbit of the Moon and beyond. Once a month around the time of the full Moon, the ARTEMIS probes will follow the Moon through the magnetotail for in situ observations.
"Orbiting the Moon is notoriously tricky, however, because of irregularities in the lunar gravitational field."
"We are particularly hoping to catch some magnetic reconnection events," says Sibeck. "These are explosions in Earth's magnetotail that mimic solar flares--albeit on a much smaller scale." ARTEMIS might even see giant 'plasmoids' accelerated by the explosions hitting the Moon during magnetic storms.

These far-out explorations may have down-to-Earth applications. Plasma waves and reconnection events pop up on Earth, e.g., in experimental fusion chambers. Fundamental discoveries by ARTEMIS could help advance research in the area of clean renewable energy.

After six months at the Lagrange points, ARTEMIS will move in closer to the Moon—at first only 100 km from the surface and eventually even less than that. From point-blank range, the spacecraft will look to see what the solar wind does to a rocky world when there's no magnetic field to protect it.

"Earth is protected from solar wind by the planetary magnetic field," explains Angelopolous. "The Moon, on the other hand, is utterly exposed. It has no global magnetism."

Studying how the solar wind electrifies, alters and erodes the Moon's surface could reveal valuable information for future explorers and give planetary scientists a hint of what's happening on other unmagnetized worlds around the solar system.

Orbiting the Moon is notoriously tricky, however, because of irregularities in the lunar gravitational field. Enormous concentrations of mass (mascons) hiding just below the surface tug on spacecraft in unexpected ways, causing them over time to veer out of orbit. ARTEMIS will mitigate this problem using highly elongated orbits ranging from tens of km to 18,000 km.

"We'll only be near the lunar surface for a brief time each orbit (accumulating a sizable dataset over the years)," explains Angelopoulos. "Most of the time we'll linger 18,000 km away where we can continue our studies of the solar wind at a safe distance."

The Dead Spacecraft Walking may have a long life ahead, after all.

Related Posts:
NASA update: ILN Anchor Nodes
and Robotic Lunar Lander Project

August 17, 2010

Aviation Week
July 30, 2010

Robotic Lunar Landers
for Science and Exploration

41st Lunar and Planetary Science Conference, #2616
March 4, 2010

ARTEMIS, A Two Spacecraft, Planetary
and Heliospheric Lunar Mission
41st Lunar and Planetary Science Conference, #1425
March 4, 2010

Update on the new lunar phase
of THEMIS mission

UC Berkeley Daily Tech
October 30, 2009

ARTEMIS to Lagrange points
to lunar orbit

April 26, 2009

Wednesday, October 27, 2010

Surveyor 7: Our fragile lunar LDEF

From Lunar Pioneer Album 2 -
Surveyor 7 (center) - last of the unmanned series, and landed furthest from the equator, north of Tycho (40.980°S, 348.491°E), January 1968. LROC Narrow Angle Camera observation M119936760LE, LRO orbit 2808, February 4, 2010, from 46.32 km. The distinctive square solar panel and mast casts a long shadow. Resolution 53 cm per pixel, spacecraft and camera skew toward target was nearly 20 degrees [NASA/GSFC/Arizona State University].

Can you located the "seemingly" big rock and craggy crater in the television mosaic returned by Surveyor 7 in the 2010 picture above? Can you see the shadow cast by the square solar panel standing on a mast above the Surveyor tripod landing platform?

Thanks to Sam Lawrence of Mark Robinson's LROC team at Arizona State University for maintaining an excellent, definitive list of human artifacts they have managed to locate on the lunar surface, using the Narrow Angle Camera (NAC) on-board LRO. By the time the scene above was imaged, on February 4, 2010 (zipping overhead at around 1.6 km per second, from an altitude of only 46.32 km), Surveyor 7 had been sitting on the Moon here, north of the Tycho for 42 years, 25 days, 14 hours, 25 minutes and 57 seconds. That means Surveyor 7 has been patiently sitting here through 568 blistering hot lunar days and super-cold nights, exposed to virtual vacuum and continuously bombarded by cosmic rays, solar wind and micrometeorites.

Because we have a documented record of the spacecraft's condition, up until losing contact with it 65 hours after its arrival here, and especially prior to its launch, chance are good Surveyor 7 (like other human artifacts on the Moon, located in a variety of places that may experience slightly different conditions, holds a pretty valuable record as a Long Duration Exposure Facility, something worth preserving for very close examination. Though this same situation - on a much shorter time scale - went into the decision to land Apollo 12 at the earlier landing site of Surveyor 3, this was secondary to testing Apollo's ability to land at a pre-determined target, and not just somewhere close. This test was a phenomenal success, vital to later missions that would land in tight spots, after negotiating their way over mountain ranges. When Conrad & Bean retrieved the television camera and robotic arm from Surveyor 3, they were examined with microscopic precision, over the course of nine months.

The report (large .pdf) proved to be a cautionary tale for future missions with the purpose of preserving these priceless baseline records of decades of exposure, some likely to be very delicate. Whether there was any accumulation of dust from the dynamic lunar exosphere on Surveyor 3 was impossible to discover, though that might also have been lost in handling anyway. Though, again, the value of Surveyor 3 as a LDEF was secondary to the Apollo 12 mission, it was eventually found that what minor pitting and paint blistering found on these parts were probably a result of the high velocity dust and debris kicked up by the descent and landing of Apollo 12. Even if Conrad & Bean had landed even closer to their intended target, a little shorter of the shallow crater where Surveyor 3 had been for thirty months, a similar contamination was inevitable.

Because of what has been since been surmised about the likely dynamism of the lunar exosphere, the migration of charged dust, and also because of a far more lengthy record of all the other conditions experienced by Surveyor 7 and the other artifacts - particularly those soft-landed - it's now considered important that future missions arrive from what once would have been considered a very great distance. Approaching these valuable "LDEF's" slowly, low to the ground is mandatory. It's also accepted that the infamous dust and debris fans kicked up by the arrival of manned and unmanned landings accelerated many particles to orbital, even escape velocity. Even arrivals at a modest distance, just over the horizon, is now considered certain to complicate a record waiting to teach us about the conditions on the Moon over an appreciable period.

As an aside, on March 21, 2010, I speculated the following image might also be of Surveyor 7. But, after a close examination it's clear I was mistaken. And after taking a look at the entire frame from which Sam Lawrence's definitive identification above was cropped, there are natural objects in the vicinity that, under the right illumination, might look a lot like the still-strange (to me) looking "thing" found in M111668133LE.

Tuesday, October 26, 2010

LROC: Highest Point on the Moon

Updated October 27, 2010 - 2005 UT

Arrow shows highest point on the Moon, 10,786 meters (35,387 feet) above the mean global radius. North is up, Sun's elevation is 16° above the horizon, image field of view is 500 meters, from LROC Narrow Angle Camera (NAC) M133865651L & R mosaic [NASA/GSFC/Arizona State University].

Mark Robinson

Principal Investigator
Lunar Reconnaissance Orbiter Camera
Arizona State University

Over the course of the Lunar Reconnaissance Orbiter mission, the LOLA team has diligently watched as the highest point on the Moon got higher and higher. No, the Moon is not expanding, but rather the LOLA profile coverage increases each month so the chances increase that a ground track will pass directly over, or very near to the highest point. Once the LOLA team had the spot narrowed down to a small area, the LROC team commanded a NAC stereo pair (12 August 2010) to get an even higher resolution measurement of the elevation and coordinates of the highest point. Once the stereo pair was on the ground, the LROC team processed the images into a digital elevation model (DEM), or topographic map.

Another view of the Moon's highest point with the Sun further above the horizon (Sun angle 48°). Image field of view is 500 meters, LROC NAC M136226953 [NASA/GSFC/Arizona State University].

The highest point on the Earth is at the summit of Mount Everest, which is 8,848 meters (29,029 feet) above sea level. The lunar high point is 1938 meters higher than that of the Earth! However there are several major differences between the two points. Mt Everest is a relatively new feature on the Earth. It was formed as tectonic plates collided and pushed up to astonishing heights what was once seafloor, over the course of about 60 million years. The lunar high point is very ancient, and was most likely formed as ejecta from the enormous South Pole Aitken basin piled up during this cataclysmic event, in matter of minutes, more than 4 billion years ago. Another key difference between the two highest points is slope. The flanks of Mt Everest are very steep, while on the Moon the approach to the summit has slopes of only about 3°, assuming you skirt around impact craters. This difference is due to the two very different formation mechanisms.

LROC Wide Angle Camera (WAC) mosaic of the Far side highlands region around the Moon's highest elevation (arrow). Engel'gradt (after Vasilij Pavlovich; Russian astronomer, 1828-1915) crater is 44 km in diameter, north is up, mosaic field of view is 100 km [NASA/GSFC/Arizona State University].

As the LRO mission progresses, knowledge of the spacecraft position improves so the accuracy of the elevation and coordinates (5.4125°N, 201.3665°E (158.6335°W) - 10,786 meters) of the highest point will improve a small amount.

The highest point is near sample 5,654 and line 29,939 in the full resolution NAC mosaic.

Related Post:
Lunar superlatives from LROC WAC
September 6, 2010

More than sixty kilometers north by northeast of the Moon's highest point is a view showing the wide variations of elevation nearby. The base of the ridge immediately below is roughly equal to the global mean average, rising to a hight of 1200 meters in a few kilometers. The distance between that closer ridge and the "plateau-like" ridge on the horizon, upon which is the 10 km highest point, is 55 kilometers. LROC NAC mosaic overlaying lunar digital elevation model available in Google Earth (>v.5).

Lunar Beagle and Lunar Astrobiology

Beagle 2 lander deployed in an idealized position. The Position Adjustable Work Station (PAW) is positioned for analysis of a rock and the Mole is ready to move across the surface.

Gibson, Pillinger & Waugh

The study of the elements and molecules of astrobiological interest on the Moon can be made with the Gas Analysis Package (GAP) and associated instruments developed for the Beagle 2 Mars Express Payload.

The Beagle 2’s analytical instrument package including the sample processing facility and the GAP mass spectrometer can provide vital isotopic information that can distinguish whether the lunar volatiles are indigenous to the moon, solar wind derived, cometary in origin or from meteoroids impacting on the Moon. As future Lunar Landers are being considered, the suite of instruments developed for the Mars Beagle 2 lander can be consider as the baseline for any lunar volatile or resource instrument package.

We suggest a possible package based on the Beagle 2 Mars lander, for delivery to a lunar polar region to conduct definitive studies in situ analysis of molecules of astrobiology importance.

Review the (pdf) proposal and rationale, HERE.

LRO-Diviner Lunar Radiometer observations of cold traps in the Moon’s south polar region

David A. Paige,1* Matthew A. Siegler,1 Jo Ann Zhang,1 Paul O. Hayne,1 Emily J. Foote,1 Kristen A. Bennett,1 Ashwin R. Vasavada,2 Benjamin T. Greenhagen,2 John T. Schofield,2 Daniel J. McCleese,2 Marc C. Foote,2 Eric DeJong,2 Bruce G. Bills,2 Wayne Hartford,2 Bruce C. Murray,3 Carlton C. Allen,4 Kelly Snook,5 Laurence A. Soderblom,6 Simon Calcutt,7 Fredric W. Taylor,7 Neil E. Bowles,7 Joshua L. Bandfield,8 Richard Elphic,9 Rebecca Ghent,10 Timothy D. Glotch,11 Michael B. Wyatt,12 Paul G. Lucey13

Diviner Lunar Radiometer Experiment surface-temperature maps reveal the existence of widespread surface and near-surface cryogenic regions that extend beyond the boundaries of persistent shadow. The Lunar Crater Observation and Sensing Satellite (LCROSS) struck one of the coldest of these regions, where subsurface temperatures are estimated to be 38 kelvin. Large areas of the lunar polar regions are currently cold enough to cold-trap water ice as well as a range of both more volatile and less volatile species. The diverse mixture of water and high-volatility compounds detected in the LCROSS ejecta plume is strong evidence for the impact delivery and cold-trapping of volatiles derived from primitive outer solar system bodies.

The Moon’s polar regions are notable because of their potential to cryogenically trap water ice and other volatile species (1). The Lunar Reconnaissance Orbiter (2) (LRO) Diviner Lunar Radiometer Experiment has been mapping the infrared emission from the Moon since July 2009 using seven spectral channels that span a wavelength range from7.55 to 400 mmat a spatial resolution of ~200 m (3).

Thermal maps of the south polar region (Fig. 1, A and B) were obtained during the LRO monthly mapping cycle just before the Lunar Crater Observation and Sensing Satellite (LCROSS) impact (4), as the Moon approached southern summer solstice (5). The mapped quantity is the bolometric brightness temperature, which is the wavelength-integrated radiance in all seven Diviner channels expressed as the temperature of an equivalent blackbody (6). For quantifying the overall heat balance of the surface and comparing with available models, the bolometric brightness temperature is the most fundamental and interpretable measurable quantity.

For the simplest case in which Diviner’s surface footprint is filled with a blackbody of uniform surface temperature, the bolometric brightness temperature will be equal to the temperature of the surface.

Figure 1. Maps of measured and model-calculated surface and subsurface temperatures in the lunar south polar region. The outer circle on all maps is 80° south latitude. Observations were acquired between 6 September and 3 October 2009 as the Moon approached southern summer solstice. (A) Diviner-measured daytime bolometric brightness temperatures acquired between 11.4 and 13.6 hours local time (5). (B) Diviner-measured nighttime bolometric brightness temperatures acquired between 21.41 and 1.66 hours local time (5). (C) Model-calculated annual average near-surface temperatures and the location of the LCROSS impact in Cabeus Crater. (D) Model-calculated depths at which water ice would be lost to sublimation at a rate of less than 1 kg/m−2 per billion years. - The white regions define the locations where water ice can currently be cold trapped on the surface, the colored regions define the upper surface of the lunar ice permafrost boundary and the gray regions define locations where subsurface temperatures are too warm to permit the cold-trapping of water ice within 1 m of the surface.

In the more general case, where Diviner’s surface footprint contains small-scale slopes, shadows, or rocks, the brightness temperatures in Diviner’s individual infrared channels may vary with wavelength depending on the distribution of sub–footprint-scale temperatures, spectral emissivities, and photometric properties. In this case, the bolometric brightness temperature cannot be interpreted in terms of a unique surface temperature. However, within cold regions that are not in direct sunlight, simultaneously acquired brightness temperatures in Diviner channels 7 (25 to 41 mm), 8 (50 to 100 mm), and 9 (100 to 400 mm) are in good agreement (6), which is consistent with uniformly high spectral emissivity across this wavelength range and relatively uniform temperatures within each Diviner footprint (fig. S1, A and B). This interpretation is supported by the results of an analysis of data acquired in each of the Diviner infrared channels at the LCROSS impact site in Cabeus Crater (7). For unilluminated regions, we use Diviner bolometric brightness temperatures as reasonably accurate proxies for the temperature of the surface.

The thermal maps show that the coldest regions are located on the floors of larger impact craters that receive no direct sunlight (Fig. 1,A and B). For these regions, previous modeling studies have shown that the main heat source is emitted infrared radiation from distant interior sunlit crater walls (8–11). Topographic relief within cold crater floor regions can provide additional radiation shielding, resulting in intensely cold localized regions with measured mid-day bolometric brightness temperatures as low as 29 K. Heat flow fromthe lunar interior may contribute to the overall heat balance of these coldest surfaces, but is not dominant compared to heating from scattered solar and infrared radiation during this season (6). Diviner’s summer solstice observations represent a valuable snapshot of the south polar region surface temperatures that can be extended in depth and in time with models. We have developed a thermal model that realistically accounts for the effects of large-scale topographic relief on direct and indirect solar and infrared radiation on the heat balance of the lunar surface (6). The model uses a ~500-m-scale triangular mesh based on south polar topography derived from the Kaguya LALT laser altimeter (12) and a spatially uniform set of thermal and reflectance parameters that are generally consistent with those derived from previous studies (6). The excellent overall agreement between maps (fig. S3, A and B) and histograms (Fig. 2A) of the observed and calculated bolometric temperatures demonstrate the general validity of our modeling approach. The only notable discrepancy occurs for daytime temperatures in the shadowed portions of craters that have measured bolometric temperatures in the range of 60 to 120 K, where the model underestimates temperatures by roughly 15 K (fig. S4, A and B). This may be largely due to directionally anisotropic infrared emission from rough sunlit crater walls, which is not accounted for in the present model (6). Given the better agreement between the model and the Diviner nighttime data, we estimate that the net effect on model-calculated annual average temperatures at 2-cm depth (Figs. 1C and 2B) is less than 7 K in the warmest craters and close to zero in the coldest craters. For the limiting case of zero heat flow from the lunar interior, the temperatures at greater depths would be close to this near-surface average temperature (11). However, with nonzero heat flow, average temperatures will increase with depth at a rate proportional to the heat flow rate and inversely proportional to the thermal conductivity. Using parameters derived from the heat flow experiments at the Apollo 15 and 17 landing sites (13), we estimate that LCROSS impact site temperatures at 2-m depth should be <6 K higher than annual average surface temperatures (fig. S5). Although the Diviner bolometric temperatures presented here and cooling curves at the LCROSS impact site are generally consistent with the presence of unconsolidated regolith near the surface (7, 14), the thermophysical properties of the Moon’s cryogenic regolith are not currently well constrained and could differ substantially from those in warmer regions (15), particularly at depth.

Figure 2. (A) Normalized histograms of measured daytime and nighttime bolometric brightness temperatures for the maps shown in Fig. 1, A and B, with comparisons to model-calculated surface temperatures at the same locations and times as those of the Diviner observations (fig. S3, A and B). (B) Histograms of model-calculated annual average temperatures at 2-cm depth for the maps shown in Fig. 1C and fig. S7, A to D, and at the LCROSS impact site for selected values of qmax, the mean maximum angle between the Moon’s spin axis and the normal to the ecliptic plane. qmax =1.54° for present-day conditions. (C) The recent evolution of qmax as a function of the Earth-Moon distance (29). (D) The volatility temperatures of a range of potential cold-trapped volatile compounds (21, 22) View higher-resolution Fig. 2 HERE.

We expect that the Moon’s cryogenic regions extend to depths of at least tens of meters below the surface, but estimating the volumetric extent of the Moon’s cryogenic regions purely from surface-temperature observations is highly uncertain.

Thermal model results can be used to estimate the stability of water ice deposits to loss by sublimation and diffusive migration through the lunar regolith (11, 16). Figure 1D shows a map of the depths at which water ice would be lost at a rate of less than 1 kg m−2 per billion years, which corresponds to a loss rate of 1 mm per billion years for a pure ice deposit (6). The results show that surface cold traps for water ice are surrounded by much more extensive “lunar permafrost” regions where water ice is stable in close proximity to the surface (17). These regions may receive direct solar radiation during periods when solar lighting conditions are most favorable, but maintain annual maximum temperatures at depth that are sufficiently cold to effectively prevent appreciable water loss due to sublimation. Because of their more hospitable surface thermal and illumination environments, lunar permafrost regions may be accessible locations for future in situ exploration of the Moon’s cold traps.

The overall picture painted by the present thermal state of the lunar south polar region is one of extreme cold. Temperatures in the Moon’s larger cold traps are closer to those expected for the poles of Pluto (18) than for Earth’s closest neighbor. At the cold temperatures that exist within most south polar craters, cold-trapped water molecules have negligible mobility (16), such that any water molecules deposited on the surface will not effectively diffuse below the surface where they can be protected from loss processes such as photolysis and sputtering (19). In cryogenic regions, burial of frozen volatiles by impact gardening is likely to be a much more effective process (20). However, warmer permafrost regions that currently exist at the margins of cold traps may represent somewhat more favorable environments for the downward diffusion of water molecules into the regolith, which should be aided by the daytime temperature gradient between warmer surface layers and colder subsurface layers below.

The distribution of temperatures in the lunar south polar region also places constraints on the thermal stability of non-water volatile species. Figure 2D shows the volatility temperatures (the temperatures at which pure solids exposed to vacuum at the surface would sublimate at a rate of 1 mm per billion years) for several volatile species (21, 22). Non-water subsurface volatiles will also be stable to sublimation at higher temperatures owing to the effects of diffusive migration through the regolith (6). Large areas of the lunar south polar region have the capability to cold-trap water and less volatile species such as mercury and sodium. All three of these volatile species were in the LCROSS ejecta plume (4, 14, 23).

Colder surface and subsurface areas in the south polar region also have the capability to cold-trap so-called super volatile species that have higher volatility than water, which include compounds such as sulfur dioxide, carbon dioxide, formaldehyde, ammonia, and methanol. The detection of a representative cross-section of these same supervolatile species in the LCROSS ejecta plume (4) represents strong evidence for the impact delivery of volatiles to the Moon by primitive outer solar system bodies, and the subsequent cold-trapping of these volatiles at the lunar poles (21, 22).

A question of interest regarding the lunar cold traps is whether they contain abundant deposits of nearly pure water ice such as those discovered by radar observations of impact craters at the poles of Mercury (24). Diviner-measured summer solstice daytime and nighttime surface bolometric brightness temperatures of 46.7 and 38.7 K in the region surrounding the LCROSS impact site, and model-calculated annual average temperatures at this site at a depth of 2 cm, are close to 38 K (6). As shown in Figs. 1, C and D, and 2B, the LCROSS impact site is a surface cold trap for water and is among the coldest locations in the south polar region. The Lunar Prospector Neutron Spectrometer (LPNS) results show that the average hydrogen abundance in the near-surface regolith at the south pole is ~70 parts per million (ppm) by weight, which translates to a water-equivalent average abundance of ~600 ppm by weight (25). Our results show that the surface and near-surface water ice cold traps comprise >66% of the surface area poleward of 85° south latitude (Fig. 1D). If we assume that all the hydrogen detected by LPNS was uniformly distributed within these cold traps, then the average water-equivalent abundance would be only ~1000 ppm by weight, which is substantially less than the 1 to 10% water content inferred at the LCROSS impact site (4). This suggests that the LCROSS site must be enriched in water compared to the average south polar near-surface cold trap, which is consistent with enhanced hydrogen abundances observed in the Cabeus region by orbital neutron spectrometers (26–28).

The spin pole of the Moon is currently in a tidally damped Cassini State 2 configuration in which the time-averaged maximum angle between theMoon’s spin axis and the normal to the ecliptic plane (qmax) has decreased to its present value of qmax = 1.54° as the Earth-Moon distance increased over time (Fig. 2C) (29). The absolute time scale for the tidal evolution of the Earth-Moon system is highly uncertain, but it is likely that the transition depicted in Fig. 2C has occurred over a period of more than 1 billion years (30). Model-calculated annual average near-surface temperatures qmax = 4°, 8°, 12°, and 16° (Fig. 2B and fig. S7, A to D) show that portions of the Moon’s south polar region cooled considerably as the Moon’s orbital radius increased, first creating cold traps capable of cold-trapping water, and then trapping compounds with higher volatility. The LCROSS impact site,which is located on the floor of the large Cabeus impact crater, is typical of the coldest areas on the Moon today. However, earlier in the Moon’s orbital history, when qmax was greater than ~10°, the floors of large-impact craters were not the coldest areas on the Moon because the walls of these relatively shallow craters did not shield their floors from direct solar radiation. Based on the results in Fig. 2B and fig. S7, A to D, the Moon’s earliest surviving near-surface cold traps are not located on the floors of large-impact craters, but rather on the floors of intermediate-sized craters, which thus may have had longer opportunities to accumulate water ice.

1Department of Earth and Space Sciences, University of California, Los Angeles, 595 Charles E. Young Drive East, Los Angeles, CA 90095, USA. 2Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA. 3California Institute of Technology, Pasadena, CA 90025, USA. 4NASA Johnson Space Center, Houston, TX 77058, USA. 5NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA. 6U.S. Geological Survey, Flagstaff, AZ 86001, USA. 7Oxford University, Oxford OX1 3PU, UK. 8University of Washington, Seattle, WA 98195, USA. 9NASA Ames Research Center, Moffett Field, CA 94035, USA. 10University of Toronto, Toronto, ON M5S 3B1, Canada. 11State University of New York, Stony Brook, NY 11794, USA. 12Brown University, Providence, RI 02912, USA. 13University of Hawaii, Honolulu, HI 96822, USA.

*To whom correspondence should be addressed. E-mail:

References and Notes:

1. K. Watson, B. C. Murray, H. Brown, J. Geophys. Res. 66, 3033 (1961).
2. G. Chin et al., Space Sci. Rev. 129, 391 (2007).
3. D. A. Paige et al., Space Sci. Rev. 150, 125 (2010).
4. A. Colaprete et al., Science 330, 463 (2010).
5. The LRO orbit plane is inclined 90° to the lunar equator and is fixed in inertial space. LRO’s ground track rotates through 360° of longitude every sidereal month, allowing Diviner to make one daytime and one nighttime map every 27.3-day mapping cycle in pushbroom nadir mapping mode. Local time on the Moon can be expressed in hours by normalizing the angular distance between geographic longitude and the longitude of the solar point to a 24-hour day. We define daytime to be between 6 a.m. and 6 p.m. local time, and nighttime to be between 6 p.m. and 6 a.m. local time. Because the plane of the LRO orbit rotates relative to the lunar terminator by 360° every Earth year, the local times of Diviner’s observations drift by ~2 hours during each mapping cycle. The subsolar latitude on the Moon currently varies by approximately T1.54° over the course of the Moon’s 346-day draconic year, resulting in distinct seasonal temperature variations at the highest latitudes. The LRO launch date was chosen so that the LRO orbit plane was within 10° of the noon-midnight plane during LRO’s first southern summer solstice.
6. Supporting material is available on Science Online.
7. P. O. Hayne et al., Science 330, 477 (2010).
8. R. R. Hodges, Lunar Planet Sci. Conf. 11, 2463 (1980).
9. D. A. Paige, S. E. Wood, A. R. Vasavada, Science 258, 643 (1992).
10. A. P. Ingersoll et al., Icarus 100, 40 (1992).
11. A. R. Vasavada et al., Icarus 141, 179 (1999).
12. H. Araki et al., Science 323, 897 (2009).
13. M. G. Langseth et al., Proc. Lunar Sci. Conf. 7, 3143 (1976).
14. P. H. Schultz et al., Science 330, 468 (2010).
15. G. J. Taylor et al., Proceedings of Space Resources Roundtable VI. LPI Contribution No. 1224., Golden, CO, Abstract 6040 (Lunar and Planetary Institute, Houston, TX, 2004).
16. N. Schorghofer, G. J. Taylor, J. Geophys. Res. 112, E02010 (2007).
17. We estimate that the total area of surface water ice cold traps in the lunar south polar region shown in Fig. 1D is 13,087 km2, and the total area of near-surface water ice cold traps to a depth of 1 m is 119,507 km2.
18. C. J. Hansen, D. A. Paige, Icarus 120, 247 (1996).
19. T. H. Morgan, D. E. Shemansky, J. Geophys. Res. 96 (A2), 1351 (1991).
20. D. H. Crider, R. R. Vonrak, Adv. Space Res. 31, 2293 (2003).
21. J. A. Zhang, D. A. Paige, Geophys. Res. Lett. 36, L16203 (2009).
22. J. A. Zhang, D. A. Paige, Geophys. Res. Lett. 37, L03203 (2010).
23. G. R. Gladstone, Science 330, 472 (2010).
24. J. K. Harmon, Space Sci. Rev. 132, 307 (2007).
25. W. C. Feldman et al., J. Geophys. Res. 106 (E10), 23,231 (2001).
26. D. J. Lawrence et al., J. Geophys. Res. 111, E08001 (2006).
27. R. C. Elphic et al., Geophys. Res. Lett. 34, L13204 (2007).
28. I. Mitrofanov et al., Lunar Planet. Sci. Conf. 41, 2250 (2010).
29. W. R. Ward, Science 189, 377 (1975).
30. B. G. Bills, R. D. Ray, Geophys. Res. Lett. 26, 3045 (1999).
31. We thank the many people at the Jet Propulsion Laboratory and the Goddard Space Flight Center who contributed to the success of the Diviner instrument and the LRO project. We also thank the National Aeronautics and Space Administration for funding this investigation.

Supporting Online Material
Methods Figs. S1 to S7
References 1 February 2010; accepted 12 August 2010 10.1126/science.1187726

Monday, October 25, 2010

Destination: Moon

From Lunar Networks: Lunar Pioneer Online
The definitive confirmation of water (and a host of exotic resources) at Cabeus, and elsewhere on the Moon, caps off a watershed moment of historic lunar exploration, all long after the Apollo era. New frontiersmen and women are taking a belated, second look at the inevitability of the Moon. And far from having already "been there" and "done that," - beginning with the humble Lunar Prospector and renewed by the political fallout following the Columbia accident, the Moon has yet again become a destination in its own right [Lunar Pioneer].

Interesting speculation are following publication of peer-reviewed studies of the LCROSS impact continues to grow. An example follows that will probably interest to LP Partners.

Yeoman Jack Kennedy of Spaceports, in an energetic column appearing in the Charlottesville Daily Progress, writes:
"The American private sector is not sitting out the next race to the moon; it is creating it. The first privately owned and operated lunar rover will be a new benchmark for free enterprise and capitalism. In the next quarter-of-a-century, we will come know a two-world system.

"While the more narrow-minded among us may consider it all sheer lunacy, the reach for the moon by foreign governments and the American private sector is a technology-driver for those of us remaining firmly on earth. The economic benefits derived from the Apollo era are staggering when cast in measure of cost accounting benefits derived and now taken for granted in telecommunications, navigation, weather prediction, health care and a host of other science and technology endeavors.

"We shall soon see the American Internet technology leaders engaging the private space development paradigm with similar vigor, innovation and creativity as witnessed in the creation of companies like PayPal, Amazon and a multitude of computer software firms."

- Back to the Moon, October 25, 2010
Kennedy, along with others, has also raised our long-anticipated question of who has rights to the Moon's resources.

President Obama, in one of his first official acts, unilaterally ended American tourism to the forbidden continent of Antarctica. And because the Outer Space Treaty of 1967 places responsibility for space-related activities by a signatory nation's citizens squarely in the hands of their respective governments (regardless where such activities may take place) can access to the Moon be blocked even to science? The answer is yes.

What role can profit play in using the Moon's resources, for any purpose? Could a new treaty, more favorable to capitalism, even be conceived at a time when Libya and even Iran sit on the United Nations Human Rights Commission?

When President Obama and, more importantly, a Congress controlled by super-majorities of his Party began eliminating the legacy for his predecessor by ending the Constellation brand name the result has really been only to defund a single significant program under development, disregarding the kinds of boosters America might need "in the pipeline." In fact, if the Lunar Reconnaissance Orbiter and the other precursor lunar robotics become the sole legacy of the Vision for Space Exploration proponents already have reason to be proud.

Lost in the fuss over boosters and architecture was Altair, the simple ability to safely land depart from the lunar surface, regardless of what such a vehicle might eventually have looked like.

The "either/or," zero-sum idea of "Moon or Mars" is a false issue. Its only natural Lunar Pioneer has welcomed the notion of private access to orbit, but no mention has yet been officially offered about similar access to the Moon's surface.

Even when Constellation's development was still in high gear the Space Studies Board of the National Academies spelled out the case for exploring the Moon systematically by precursor robotics "prior to extended human activity," to better understand lessons to be learned while the Moon remains relatively "pristine." But the Board also anticipated events rapidly catching up with such a need (regardless of American timetables).

Another story today from China's Peoples Daily reminds us of what might seem only minimally important to many, that is until China's increasing reluctance to part with its near monopoly of certain rare earths, essential to much of the world future economy, is taken into account:
"The Chang'e II, China's second lunar probe, conducted an imaging tests of its CCD camera yesterday and it will track down and enter into an orbit around the moon of 100 kilometers by 15 kilometers on Tuesday by an enhanced thrust from the launch vehicle.

"After the third image tests, the Chang'e II will enter into and image the Rainbow Bay, the landing area for the satellite.

"The imaging tests of the CCD camera aboard the satellite started yesterday in the early morning. It ceaselessly conducted the work of interruption and restoration of power supply and flew around the moon every two hours, according to Zhang Bo, chief designer of the Beijing Institute of Tracking and Communication Technology.

"The three imaging tests are just preparations for the imaging of the Rainbow Bay, said Zhang.

"Yesterday's imaging tests show the camera works well and Chang'e II is still running around an orbit of 100 kilometers by 100 kilometers."

Liang Jun, People's Daily Online
Lost in translation, of course, is that "the satellite" China intends to land is not Chang'e-2,but Chang'e-3, and then not before 2013.

Why has the Chinese Lunar Exploration Program (CLEP) decided upon Sinus Iridum, their "Rainbow Bay" as a future landing target candidate?

Officials say the half crescent bay on the northwest edge of the Iridium basin is only one possible target. China space-watchers might want to trace out other areas where Chang'e-2 will swing closer to the Moon at perilune, along this same middle latitude before and after the Moon's rotation brings "Rainbow Bay" within range of its improved optics.

It seems to be an exceptionally flat place, known for low reflectivity in Earth-based radar. It is surrounded by, but not really a significant part of, the Procellarum KREEP terrain, recognized for an unusual combination of potassium, rare earths and phosphorus, nor is Rainbow Bay really part of the broader area on the Moon's Near side known for high relative abundance of nearly every kind of metallic oxide and thorium.

Courtesy of the venerable Astrogeology section of the United States Geological Survey (USGS), three context views of the Sinus Iridum venue (small Red dot), all Mercator projections (1/2 degree per pixel). At top, the Moon in "natural color" from the Ultraviolet-Visible Light (UVVIS) survey from Clementine (1994), and at middle and bottom the relative elemental abundance of thorium and, at bottom, oxygen from surveys by Lunar Prospector (1998-1999). Iron oxide (mapped elsewhere) is thought to be a good marker for the highest probable presence of helium-3. Though Sinus Iridum is clearly of morphological interest, it is not particularly rich in thorium and less rich in oxygen (and oxides) than most Near side basalt-filled areas on the Moon [USGS].

Perhaps, along with areas in Africa and the Americas, the always forward-thinking Chinese are looking to secure resources on the Moon. Then again, perhaps the methodical Chinese Lunar Exploration Program (CLEP) is simply learning the delicate skill of orbital targeting in their stated ambition of shortly landing Chang'e-3 on a wide and flat target.

Nevertheless, premature speculation about the PRC's lunar intentions, based on their present and more obvious strategic priorities, is just starting to run high:
Rare metals on the Moon have yet to spark modern Moon race

Minyanville Daily Feed
Cory Bortnicker October 25, 2010

China’s abundance of rare earth metals has been the talk of the town, as of late. And for good reason. They’ve got about 90% of the Earth’s supply of compounds like Neodymium, Dysprosium, Cerium and thus, can dole them out as they wish while the rest of the world squirms, begs, and barters.

But thanks to a little known science called “astronomy,” there could be an alternative locale for mining rare Earth metals…the moon.

The AFP reports that researchers at Brown University have analyzed particles of lunar dust and found a “surprisingly rich mixture that, in addition to the silver, included water and compounds like hydroxyl, carbon monoxide, carbon dioxide, ammonia, and free sodium.”

Brown geologist Peter Schultz said “This place looks like it's a treasure chest of elements, of compounds that have been released all over the Moon.”


And the best news? The US has serious plans to launch extensive missions to the moon! Er…actually, scratch that. Not the US. We mean China.

On October 11th, President Obama signed the NASA Authorization Act 2010, effectively ending the Constellation program, which aimed to return humans to the Moon.

Meanwhile, on October 1st, the Chinese Lunar Exploration Program (CLEP) launched its Chang E 2 lunar probe, the second lunar orbiter launched in three years. In 2004, the Chinese government authorized a three-stage robotic lunar exploration that will:

Stage 1: Orbiters will circle the moon and collect data.

Stage 2: Robotic probes will land on the lunar surface to collect and analyze lunar samples and transmit the data back to Earth.

Stage 3: After landing on the moon, the robotic probe will return to Earth with a set of moon rocks and soil sample.

NASA’s behind-the-times approach isn’t lost on NASA Administrator Charles Bolden, who recently traveled to China for talks about cooperative spaceflight.

As you can imagine, lawmakers are less than thrilled.

Rep. Frank R. Wolf (R-Va.), who is on the subcommittee that oversees NASA’s budget, wrote “It should go without saying that NASA has no business cooperating with the Chinese regime on human spaceflight. China is taking an increasingly aggressive posture globally, and their interests rarely intersect with ours."

POSITION: No positions in stocks mentioned."
These seem like wild speculations now, based in part on outdated science, yet thinking in this manner about the Moon, as a destination rather than as mere stepping stone, has begun once again, some writing driven by agendas based upon thinking pretty far afield from the expansion of a human permanent presence beyond the confines of our single planet, the one the dinosaurs too late discovered a sitting target.

A very recent study has also appeared speculating that "soot" from an eventual 1,000 suborbital tours by the Virgin Galactic SpaceShipTwo (supposedly using only one particular rocket design during that entire extended period) would result in more so-called "global warming" than would result from all of the world's civil aviation.

With the confirmation of a tally of elements uncovered at Cabeus comes chatter about a need to understand the "pristine" lunar exosphere, as well as the Moon's long record of the Solar System's history, before any extended human activity on the Moon.

The landing site of Apollo 16, for a variety of reasons, is among the Fifty priority Constellation program Regions of Interest. At one time believed to have proved out as a mistaken choicethe Cayley Plain between North and South Ray craters, in the shadow of the Descartes formation has become a standard for calibrating remote sensors, on board Japan's Kaguya, for example. Artifacts of the Young & Duke expedition are invaluable as a long-duration exposure facility (LDEF). Based on studies of the similar, though secondary purposes for landing Apollo 12 near Surveyor 3 in 1969, the authors in 2008 recommended any future approach here "low and from a distance" - quite different than the notion pictured above. For a wallpaper-sized view (1920 x 1100), click HERE [Lunar Pioneer].

Thankfully, no tie into the world's ecosystem and food chain, no fauna or flora, has yet been discovered on the Moon or the "temporary" status of Antarctica set up more than fifty years ago might eventually set the economic salvation available from the Moon in a tragic and unnecessary limbo. Those who favor ignoring the Moon in hope of moving on to Mars - a place far more likely to harbor life - should pay close attention.

Love of humanity, among humans, is not universal.

Even setting aside the possible future harvesting of helium-3 for a clean fusion power, we are facing a simple harsh reality. For the human race to continue its present technological and economic growth - for the world at large to enjoy even the most basic kind of lifestyle now enjoyed in the United States, for example, beyond 2050 we will very likely need what the Moon has to offer.

There is no reason why both the learning of the lessons that the Moon has to offer while enriching our species in the process cannot go hand in hand - unless, of course, some are simply unwilling to simply step out of the way. If that should eventually prove impossible, there is another and more traditional kind of extended human activity to settle the issue, though such methods might also serve to unnecessarily delay the fulfillment of both these noble purposes.

Sunday, October 24, 2010

Kaguya HDTV: Imaging Earth and Moon

HDTV image near Andersson (50◦S, 262◦E) from an altitude of 11 km, by the WIDE camera on board SELENE-1 (Kaguya), April 16, 2009. The controlled impact of the spacecraft occurred Moon at 18:25 (UT), June 10, 2009. View the full-size image, HERE [JAXA/NHK/SELENE].

Yamazaki & Mitsuhashi,
NHK (Japan Broadcasting Corporation)
October 12, 2010

High-Definition Television (HDTV) system has a resolution that is twice that of conventional television in terms of both vertical and horizontal resolution and a wider picture aspect ratio of 16:9. Research and development into HDTV was started in the 1970s by NHK (Japan Broadcasting Corporation) (Fujio et al. 1980, 1982). The HDTV system, characterized by its higher resolution and wider picture aspect ratio, appeals strongly to viewers thanks to the “presence” of its images, and has been adopted in many Japanese households. HDTV was firstly carried into space in 1998 onboard the Space Shuttle. Imaging of the Earth from a spacecraft in an Earth-revolving orbit was conducted manually by an astronaut.

In order to load the system into a manned spacecraft, the system was examined and improved with respect to toxic substances, fire prevention, and electromagnetic radiation in the communication frequency band (Yamazaki 2001). NASA’s (National Aeronautics and Space Agency) evaluation was that a three-CCD type HDTV had a color representation closer to natural color than that of film or a single-CCD camera, and thus was most suitable for observations of the Earth (Robinson et al. 2000). However, a HDTV system had not been sent into deep space onboard an unmanned spacecraft.

Another "normalized" take on the Kaguya HDTV now-iconic “Earth-set” behind Malapert Massif, Shackleton and the lunar south pole, obtained by the TELE camera November 7, 2007. Full-sized, full-width view, HERE [JAXA/NHK/SELENE].

The first still image of the Earth viewed from space was taken by the weather satellite TIROS-1 on April 1, 1960. The image of an “Earth-rise” from the lunar horizon was acquired by an Apollo 8 astronaut with a 70 mm film camera on December 22, 1968. The first movies of the Earth, the Moon and the lunar landing module were shot by Apollo 11 astronauts using a video camera on July 16, 1969. No other videos of the Earth and the Moon were acquired from lunar orbit from the completion of the Apollo mission until 2006, though still images of Moon were acquired by Clementine UV/VIS camera (Nozette et al. 1994) and SMART-1’s AMIE multicolor micro camera (Josset et al. 2006).

The lunar-orbiting explorer Kaguya/SELENE (Selenological and Engineering Explorer) was developed by JAXA (Japan Aerospace Exploration Agency) to conduct scientific observations of the lunar surface and the environment around the Moon using 15 mission instruments while in a lunar-revolving orbit. The HDTV system was selected in 2001 as the last mission instrument to be carried onboard the Kaguya. The primary objective of adopting an HDTV system was the acquisition of high-resolution movies of the Earth and the Moon, in particular the Earth-set and the Earth-rise from the Moon, for public outreach purposes.

Following the launch of the spacecraft atop an HII-A rocket on September 14, 2007, from the Tanegashima Space Center in Japan, Kaguya’ s HDTV system acquired clear moving images of the lunar surface and the Earth until the end of the mission on June 11, 2009 (e.g., Honda et al. 2008a; Mitsuhashi et al. 2008). The total amount of images obtained by the HDTV system was 6.3 TB. Although the primary objectives of using the HDTV system were public outreach and to record images for educational purposes, the HDTV images are currently expected to also be useful in lunar surface studies because of the characteristics afforded by the HDTV system, such as oblique views and sequential data acquisition (Honda et al. 2008b, 2009).

A perspective view of the lunar surface acquired by HDTV is helpful in acquiring a general view of lunar features on a 100-km scale. In addition, HDTV movies are adequate for the observation of an opposition surge on the lunar surface, as well as the transient phenomena such as glow over the lunar horizon after sunset or before sunrise, and the Earth’s “diamond ring” shown in Sect. 8.

This paper describes the specifications of the HDTV system and onboard data processing, as well as the data obtained during the mission period.

View the Springer description and abstract, HERE.
Read the full technical report text (pdf), HERE.

Saturday, October 23, 2010

Where are the wettest places on the Moon

High resolution (~15 km) polar maps of collimated epithermal neutrons created by the LRO Lunar Exploration Neutron Detector (LEND) team. The permanently shadowed region at Cabeus shows an indication of 4% hydrogen (by weight), while the Shoemaker crater neutron suppression signature, entirely within a widespread PSR, shows a signature consistent with 2%. Note that the crater Faustini, similarly situated and permanently shadowed, shows a very average polar neutron suppression. The reason for this disparity is not yet known.

The Lunar Exploration Neutron Detector (LEND) flying with LRO has enabled investigators to create high-resolution (15) km) maps of the collimated epithermal neutron counting rate over the lunar poles.

Overlapping these data upon new and improved maps of the Moon's confirmed permanently shadowed regions (PSRs) there has proven puzzling. Though the neutron suppression maps from Lunar Prospector had already strongly hinted that hydrogen, most likely in the form of water ice, might be more widespread - outside - permanent shadow - than cold trap placement models yet suggested, many attributed this to the low resolution of the 1999 neutron instrument.

Now LEND has identified several of what are being called "Neutron Suppression Regions," using only neutron measurement data, and the result has been what are now three types of NSRs. There are NSR's "well-correlated" with a PSR, NSRs well-correlated with a part of a PSR that nevertheless stretch well outside the shadows into areas illuminated by the Sun. Finally, there are NSRs not correlated with any large PSR. In fact, taken in all, there are as many areas typified by neutron suppression outside permanent shadow as inside.

The picture developing of the new lunar hydrology, a daily cycle and the volatiles (and now additionally a surprising variety of exotic elements and compounds) stuck within polar cold-traps is has led to yet another rediscovery of the Moon.

Below are links to the slide presentations (pdf) that accompanied the LEND team's reports about their findings made to the Annual Lunar Exploration Analysis Group (LEAG) Conference on September 16, 2010:

Main Results from LEND Instrument After One Year of Lunar Mapping Onboard NASA’s LRO
Mitrofanov, Litvak & Sanin,

Which Spot on the Moon has the Highest content of Hydrogen?
Sanin, Mitrofanov & Litvak,

Much of the Hydrogen Enrichment near the Lunar South Polar is Outside the Permanently Shadowed Regions
Boynton, Mitrofanov & Sanin,

LRO laser altimetry (LOLA) together with neutron suppression measurements (LEND) are combined to show the 72 sq. km permanently shadowed region targeted by LCROSS is not the only contiguous area there where a neutron suppression consistent with the hydrogen (in the form of water) has been detected. Areas outside the white boundary are regularly illuminated by the Sun. (Larger view, HERE) [NASA/LOLA/LEND].