Friday, February 27, 2015

Review: the Moon as 'blue water port' to the stars

Moonscraper 2040 - Honorable Mention: 2011 Skyscraper Competition [Luis Quinones].
Jessica Guenzel
Phys Org

"Crotts' new book, titled The New Moon: Water, Exploration, and Future Habitation, explores his innovative ideas and many more in meticulous detail, providing hard scientific findings that topple decades-old ideas about the moon's development and structure. Readers may well wonder why the U.S. abandoned its lunar exploration program in 2010, just as so many discoveries were emerging.

"Today, we know that billions of tons of water exist on the moon in the form of ice, and Crotts is sure that more will be found. It's not likely the kind of H2O earthlings drink but rather one rich in heavy water—or deuterium oxide—a form of water in which the hydrogen atom's nucleus is double the mass of ordinary hydrogen, rendering it undrinkable by humans without processing.

"Crotts believes the moon's water could be broken down into liquid hydrogen and liquid oxygen, a potent mix that makes an ultra-efficient form of rocket fuel, the same kind that powered the NASA Saturn V rockets that boosted the Apollo spaceships out of Earth's atmosphere towards the moon.

"You'd have to look hard to find another propellant that's as efficient or better," said Crotts. The moon also has carbon monoxide that Crotts said could be converted with water into methane, another efficient and powerful rocket fuel.

"With all that potential rocket fuel, Crotts naturally believes that the moon could one day be transformed into an interplanetary gas station for the satellites and rockets that today get discarded because they eventually run out of fuel and drift into the wrong orbit."

Read the full review, HERE.

Wednesday, February 25, 2015

Lunar Orbiter Image Restoration Project: Last Mile

Until the original tapes were found, stored in an abandoned McDonalds Restaurant on site at Ames Research Center, and subsequently read and remastered using totally unavailable equipment built from scratch, this represents our best view of of the rugged slopes of the central peaks of Copernicus crater, a facsimile of a photograph developed in lunar orbit and radioed back to Earth from Lunar Orbiter V, August 17, 1967. For comparison, see the photographs that follow below [USGS]. 
From moonandback video, May 2010
Dennis Wingo

The Lunar Orbiter Image Recovery Project (LOIRP) is a public/private project to recover, from the original master tapes, the image data from the five spacecraft NASA sent to the moon in the 1960’s and provide it to the scientific community and the public.  The first is done through a peer review process and then the data is provided to the National Space Science Data Center (NSSDC) for archiving.  We also have a public website through NASA at the Solar System Exploration Research Virtual Institute (SSERVI) at the NASA Ames Research Center.  This missive is to explain the background of the mission, the character of the data, and why it is important to our scientific and national history.

At this time we have completed over 90% of the work necessary to archive and publish these images.  However, sometimes that last 10% is the hardest and we have in the dozens of terabytes of data to complete the processing of our image captures.  Why doesn't NASA pay for this?  They have paid for the vast majority of our work.  NASA’s Space Science Mission Directorate, NASA Ames, and and SSERVI have been magnificent in support of our work.  However, NASA’s budget is severely constrained, and for legacy projects like this, it is our work in technoarchaeology (literally the archaeology of technology) that is saving this data for posterity.

Field of view captured in by Lunar Orbiter V in 1967, shown in the image further above, outlined on a more recent photographic survey by the Lunar Reconnaissance Orbiter (LRO), LROC M181302109R, spacecraft orbit 11832, January 15, 2012 [NASA/GSFC/Arizona State University].
When we started this project, it was only to save the images of Lunar Orbiter’s II and III.  However, in 2011 NASA asked us how much it would cost to complete all five orbiters.  We estimated $400,000.  NASA provided $300,000 of this, leaving a gap of $100,000.  This is why we ask for your support in our crowdfunding effort, to complete this task.  These images, provided on the SSERVI website, will be free to the public with no copyright.  The American taxpayer paid for this effort and even though our company has also contributed materially to the effort and we are extending this through your generous donations through crowdfunding, we want this to be provided free of charge, or any intellectual property right restrictions.

Detail from LOIRP Lunar Orbiter V (Image 151-H1 -Copernicus Central Uplift) The LOIRP Image was derived from the original analog tapes from the LO ground stations and has 4x the dynamic range of the LO film archive. This image with a resolution of about 2 meters, taken on August 16, 1967 from 103 km. This version of the LO-V-151-H image is from the original ground station tape from the Woomera ground station in Australia (tape W5-58).
NASA had stored these original analog data tapes for over four decades, but if it were not for our project and former NASA archivist Nancy Evan’s preservation of the tape drives in her barn, this archive at its best quality would be lost to history.  Following is a description of the Lunar Orbiters, their camera, the images and what we are doing to preserve this legacy of the early Apollo program.

Background on the Lunar Orbiter

In 1966-67 NASA sent five spacecraft to the Moon to do a high resolution photo reconnaissance of the surface in preparation for the manned Apollo lunar landings.  This was the first time in human history, other than a few closeups before impact from the Ranger spacecraft, that the moon had been seen up close and personal.

Enjoy the full post from Dennis Wingo, HERE.

Related Posts:
The LOIRP time machine looks back 43 years (June 3, 2010)
New releases from Lunar Orbiter II (1966) - (May 7, 2010)
Boulders of Copernicus (December 11, 2009)
LOIRP: Boulder Trails on the Moon (December 10, 2009)
Lunar Orbiter's originals vs. LOIRP restorations (December 9, 2009)
New restored detail from Lunar Orbiter II (December 8, 2009)
LOIRP configures second FR-900 tape drive (November 12, 2009)
The importance of lunar water (September 28, 2009)
LOIRP remasters the Moon's South Pole (August 14, 2009)
Lockheed Martin donates Clean-Room to LOIRP (August 12, 2009)
LOIRP astounds again, re-release of LO-II0162 (1967)
with each of three high-res sub-frames
 (August 10, 2009)
Full Earth, as seen by Orbiter V (August 7, 2009)
Lunar Orbiter III-154-H2 (June 16, 2009)
LOIRP recovers Lunar Orbiter IV lunar South Pole image from 1967 (June 16, 2009)
LOIRP recovers detail of Fra Mauro and future landing site of Apollo 14 (June 11, 2009)
New LOIRP high res Lunar Orbiter image of western Oceanus Procellarum (June 10, 2009)
LOIRP recovers image of Ranger 8 impact (June 9, 2009)
LOIRP's "Pictures of the Century" (March 23, 2009)
More astounding new detail from LOIRP (February 26, 2009)
Breakthrough in Lunar Orbiter photograph remastering (February 20, 2009)

Tuesday, February 24, 2015

Astrobotic, Hakuto team up to ride Falcon 9 to Moon

The combined strategy utilizes the Astrobotic "Griffin" lander (carrying their "Red Rover," in foreground) to deploy a total of three robotic rovers, including the Hakuto "Tetris" and "Moonraker" [Astrobotic/CM].
Angela Moscaritolo

Two rivals battling it out in Google's $30 million competition to land a private spacecraft on the moon are teaming up for a joint trip to the lunar surface.

Hakuto, the only Japanese team competing in Google's Lunar XPrize competition, and Pittsburgh-based Astrobotic on Monday announced they are partnering for a moon journey during the second half of 2016.

Hakuto rover Moonraker (and back-up) undergoing hazard and slope avoidance testing in 2014 [Tim Stevens/C|NET].
The plan is that Hakuto's twin rovers — dubbed "Moonraker" and "Tetris" — will "piggyback" on Astrobotic's so-called "Griffin" lander to reach the moon.

Hatuto sub-rover Tetris [Tim Stevens/C|NET].
Astrobotic will launch the mission next year on a SpaceX Falcon 9 rocket from Cape Canaveral, Fla. After touching down, Hakuto's rovers will be simultaneously released alongside Astrobotic's "Andy" rover, developed by Carnegie Mellon University.

Read the full story HERE.

Additional story at Pittsburgh Business Times, HERE.

Astrobotic Technology Red Rover design concept, picked by Popular Science as one of 100 Best Innovations of 2011.

Monday, February 23, 2015

SDI: Military uses of the Moon and Asteroids (1983)

NASA/DOD joint lunar reconnaissance and instrument test platform Clementine, "lost and gone forever" following its remarkable and successful mission in 1994.
David S.F. Portree

On the evening of 23 March 1983, President Ronald Reagan addressed the people of the United States from the Oval Office. Citing aggressive moves on the part of the Soviet Union, he defended proposed increases in U.S. military spending and the introduction of new missiles and bombers. He then called for a revolution in U.S. strategic doctrine:

Let me share with you a vision of the future. . .What if free people could live secure in the knowledge that their security did not rest upon the threat of instant U.S. retaliation to deter a Soviet attack, that we could intercept and destroy strategic ballistic missiles before they reached our own soil or that of our allies? I know this is a formidable technical task, one that may not be accomplished before the end of this century. . .I call upon the scientific community in our country, those who gave us nuclear weapons, to turn their great talents now to the cause of Mankind and world peace, to give us the means of rendering these nuclear weapons impotent and obsolete.

Thus was born the Strategic Defense Initiative (SDI), which is perhaps better known by its cinema-inspired nickname “Star Wars.” This post is not meant to discuss the geopolitical ramifications or technical feasibility of SDI. It will instead focus on a lesser-known aspect of SDI planning.

Read the fascinating full story at WIRED, HERE.

Sunday, February 22, 2015

Apollo era museum in Salado, Texas

Ron Finkle and a primary exhibit in his remarkable home-based museum of the Apollo program, between Waco and Austin in Texas [Michael Miller | FME News Service]
Deborah McKeon
FME News Service
Killeen Daily Herald

Belton — Ron Finkle grew up during the Apollo era, a time in history he said he’s pretty sure won’t ever be repeated.

Finkle’s fascination with space exploration inspired him to create a small aviation museum in his home consisting of scale models he built and had commissioned, as well as autographs.

A centerpiece of that museum is now a lunar roving vehicle model that Finkle designed and built.

Although many scale-model companies re-created the command module, the crew’s quarters and flight control section, the service module for propulsion and spacecraft support systems, none has recreated an authentic-looking land rover, Finkle said.

The lunar roving vehicle allowed astronauts to travel farther on the moon’s surface during the last three missions of the Apollo program, according to the National Aeronautics and Space Administration.

Finkle spent about six months from start to finish on the land rover, revising it seven times and tweaking it each time, he said.

Daniel Tagtow with Innovate, a product development company based in Austin, created the computer designs, coming up with the specifications for the scale model. Those figures were approved by Finkle and sent to Stratasys Direct Manufacturing, a 3-D printing company in Belton.

Read the full story, HERE.

Saturday, February 21, 2015

Students build dust mitigation experiments with NASA

Students at two Hawaii schools have teamed up with NASA to develop lunar dust mitigation experiments which may be tested  on Google Lunar X-Prize contestant landers in the near future [HawaiiNewsNow].
Lisa Kubota

Students at two Hawaii schools are embarking on a new space mission. They're teaming up with NASA on an experiment that is heading to the moon. Students at Iolani School and Kealakehe High School have been working on the lunar project for months now. NASA developed the electrodynamic dust shield (EDS) to repel pesky planetary dust that gathers on space gear. The technology, which uses electricity to clear off surfaces, hasn't been tested yet in space.

"The dust on the moon is very sharp and scratchy so during NASA's Apollo experience they found that the astronauts were coming back with visors that they basically couldn't see out of because it had gotten so dusted up and scratched up when they tried to wipe them off," explained Iolani teacher Gilson Killhour.

The project involves NASA, the two schools, the Pacific International Space Center for Exploration Systems (PISCES) and a Google Lunar X-PRIZE team. Each campus built a mockup lander and designed a frame for the dust shield.

"It's a very unique opportunity that's probably a once-in-a-lifetime thing and I'm glad I was able to jump on it and be able to participate," said Iolani senior Keegan McCrary.

"If they do make it to the moon, they'll test their own test for Google and then they'll test ours, which is the EDS. They'll have the rover, which is back there, and it will circle around and video," said Iolani senior Veronica Shei.

The students will test their experiment at a PISCES site high atop Mauna Kea next month.

View the original report, HERE.

An additional report on this topic was produced by Cam Tran at KITV (Honolulu), HERE.

The search for transient frost using laser altimetry

Laser altimetry map of the Moon's northern polar region, north of 80° at 20 meters resolution. The crater Lovelace (57.06 km; 82.08°N, 250.49°E), referenced below, is southwest of Hermite, where the lowest temperatures yet recorded in the Solar System have been measured on the pole-facing walls, in permanent shadow [NASA/GSFC].


M. Lemelin,
University of Hawaii at Manoa

Introduction: The possibility of lunar polar ice was suggested by Harold Urey in the 1950's [1], and has likely been directly detected at the North Pole of Mercury by MESSENGER. That detection was based on the presence of reflectance anomalies seen by the Mercury Laser Altimeter (MLA) that occurred only where models of the surface temperature allow long-duration preservation of surface water ice against sublimation [2,3].

Anomalous reflectance is also seen at the lunar poles, revealed by laser measurements. The reflectance of permanently shadowed regions is systematically higher than nearby areas that receive at least some illumination [2,3,4] (Fig. 1). Models suggest that if the higher reflectance is due to the presence of water ice; up to 14 wt.% could be present depending on the distribution of frost within or on the regolith.

Figure 1. DIVINER maximum temperature (left) and LOLA reflectance (right) for the north polar crater Lovelace. The blue patch in the temperature image shows the location of a permanently shadowed region. The corresponding location in the reflectance image clearly show higher reflectance than the surroundings
Results of lunar observations by the Deep Impact High-Resolution Instrument – Infrared spectrometer (HRI-IR) in the 3 μm region and by the Lunar Reconnaissance Orbiter (LRO) Lyman Alpha mapping project (LAMP) in the far-UV region both show that spectral features consistent with hydration of the surface are diurnally variable. This indicates that water is pos-sibly mobile on the lunar surface [5,6]. Because the lifetime of water molecules in the lunar atmosphere is short against dissociation (~20 hours) compared to the lunar diurnal cycle, water must be continuously pro-duced to account for the observations. Mobile water will trap on cold surfaces during the lunar night and be released when surfaces are illuminated during the day.

In this study, we seek evidence for transient water frost on the polar surfaces using reflectance data from the Lunar Orbiter Laser Altimeter (LOLA), and temperature data from the DIVINER radiometer, both onboard the LRO. We aim to search for areas that may “load” with surface frost during the night causing in-creased reflectance, and unload during the day reducing the reflectance. Detection of transient surface frost constrains the rate of input into the lunar volatile system.

Methods and datasets: LOLA measures the backscattered energy of the returning altimetric laser pulse at 1064 nm. This data is used to map the reflectivity of the Moon at zero-phase angle with a photo-metrically uniform data set. The zero-phase geometry is insensitive to lunar topography and enables the characterization of subtle variations in lunar albedo, even at high latitudes where such measurements are not possible with the Sun as the illumination source. The DIVINER radiometer simultaneously measures the bolometric temperature of the lunar surface.

To find evidence of transient surface frost, we examined locations where reflectance data from LOLA exists at both low (less than 156 K, a loss of 100 μm of frost per month or less, sufficiently cold for ice to persist during a single lunar night [7,8]) and high temperatures (greater than 201 K, a loss of 1 mm of frost per month or more, no possibility of retaining surface ice [7,8]) using the DIVINER radiometer data, seeking changes in albedo with temperature. We search the LOLA reflectance dataset for locations that have reflectances measured at both low and high temperatures using DIVINER tem-perature measurements obtained simultaneously with LOLA data. For this initial search, we examined both polar regions at a spatial resolution of 2 pixels per degree (~15 km per pixel), within ±50-90º latitude.

Initial Results: For both polar regions (±50-90º latitude), we find that most of the pixels outside permanently shadowed regions are subject to both low (less than 156 K) and high (greater than 201 K) temperatures. Figure 2 shows the LOLA reflectance data for both poles when the temperature of a given pixel is either greater than 156 K (Fig. 2 left) or greater than 201 K (Fig. 2, right).

Methods and datasets: LOLA measures the backscattered energy of the returning altimetric laser pulse at 1064 nm. This data is used to map the reflectivity of the Moon at zero-phase angle with a photo-metrically uniform data set. The zero-phase geometry is insensitive to lunar topography and enables the characterization of subtle variations in lunar albedo, even at high latitudes where such measurements are not possible with the Sun as the illumination source. The DIVINER radiometer simultaneously measures the bolometric temperature of the lunar surface.

By subtracting the 1064 nm reflectance when the temperature is high (greater than 201 K) from the reflectance when the temperature is low (below 156 K), we find that the global difference in reflectance averages near 0 for both polar regions (Fig. 3). Therefore, we do not detect a general temperature dependent reflectance variation.

Figure 2. LOLA 1064 nm reflectance for (A) the North Pole and (B) the South Pole. The reflectance when the temperature is low (less than 156°K) is shown on the left and the reflectance when the temperature is high (greater than 201°K) is shown on the right.
Figure 3. LOLA 1064 nm reflectance difference between the reflectance when the temperature is high (greater than 201° K) and when the temperature is low (less than 156° K), for (A) the North Pole and (B) the South Pole.
Discussion and future work: We did not detect a general temperature dependent reflectance variation in our study for either polar region with a detection precision of about 1%. Using a simple model of a nonabsorbing layer over an absorbing substrate, a very small optical depth is required to raise the reflectance by 1%, only 0.045 ([9] Section 9.D.2). This corresponds to ~30 μg/cm2, a layer thickness of about 300 nm. In comparison, the observations of [5,6] require a layer thickness of at least 10's of nanometer to account for the observed band depths. This suggests that our current measurements are at the edge of detection of the source implied by the spacecraft observations. In contrast to the implications of the reported measurements, the solar wind can provide far less water; concentrated in a single layer, calculations by [10] suggest only 0.01 nm globally averaged per month.

Our current analysis did not take into account how long each surface element has been subject to cold temperatures (i.e., if it had time to accumulate frost). For example, based on a Monte Carlo model, Schorghofer (2014) [11] showed that a continuous source of water molecules arriving on the lunar surface (regardless of the source) would significantly accumulate near the morning terminator. Additional calculations show that the morning terminator should feature about 30 times the concentration of the average nightside abundance, improving prospects for detection. 

Future work includes reanalyzing existing data to include the time of exposure at low temperatures, and conducting targeted observations with LOLA to observe night time polar surfaces near the morning terminator in order to improve the upper limits of detection on transient water frost.

References: [1] Urey H. C. (1952) The Planets: Their Origin and Development. Yale University Press, New Haven, CT, 245 pp. [2] Paige D. A. et al. (2013) Science, 339, 300-303. [3] Neumann G. A. et al. (2013) Science, 339, 296-299. [4] Zuber M. T. et al. (2012) Nature, 486, 378-382. [5] Sunshine J. M. et al. (2009) Science, 326, 565-568. [6] Hendrix A. R. et al. (2012) JGR Planets, 117, E12001. [7] Zhang J. A. and Paige D. A. (2009) GRL, 36, L16203. [8] Zhang J. A. and Paige D. A. (2010) GRL, 37, L03203. [9] Hapke B. (1993) Theory of reflectance and emittance spectroscopy, Cambridge. [10] Hurley D. M. and Farrell W. M. (2013) LPSC 44, abstract #2015. [11] Schorghofer N. (2014) GRL, 41, 4888–4893.

Acknowledgments: This work is supported in part by the LRO LOLA experiment (David Smith PI), the LRO Diviner experiment (David Paige PI), and the Natural Science and Engineering Council of Canada (NSERC).

CRaTER: Lunar Proton Albedo Anomalies

Figure 1. Top: Lunar albedo proton yield map (cylindrical projection) with anomalous yield regions labeled “A” through “E”. Regions A (Mare Serenitatis) and B (Oceanus Procellarum) are both centered near the boundaries of mare regions. Regions C, D and E are all in the highlands on the far side of the Moon. Bottom: Visible global composite image from the Lunar Reconnaissance Orbiter Camera (LROC).


J.K. Wilson, N. Schwadron and H. E. Spence, et al.
Space Science Center
University of New Hampshire, Durham

Introduction: Since the launch of the Lunar Reconnaissance Orbiter (LRO) in 2009, the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) has been mapping albedo protons (~100 MeV) coming from the Moon [1,2].

These protons are produced by nuclear spallation, a consequence of galactic cosmic ray (GCR) bombardment of the lunar regolith. Just as spalled neutrons and gamma rays reveal elemental abundances in the lunar regolith [3-6], albedo protons may be a complimentary method for mapping compositional variations across the Moon’s surface.

Albedo Proton Yield: The CRaTER instrument simultaneously detects albedo protons from the Moon and GCRs arriving from the zenith direction. We divide the number of albedo protons observed over each point on the Moon by the number of GCRs detected over the same location to produce a map of the yield of albedo protons.

We presently find that the lunar maria have an average proton yield which is 0.9% ± 0.3% higher than the average yield in the highlands; this is consistent with some neutron data that shows a similar yield dichotomy due to differences in the average atomic weight between mare regolith and highland regolith [7].

Map Features: There are cases where two or more adjacent pixels (15° × 15°) in the map have significantly anomalous yields above or below the mean.

These include two high-yielding regions in the maria, and three low-yielding regions in the far-side highlands. Some of the regions could be artifacts of Poisson noise, but for completeness we consider possible effects from compositional anomalies in the lunar regolith, including pyroclastic flows, antipodes of fresh craters, and so-called "red spots" which are associated with volcanic domes. We also consider man-made landers and crash sites that may have brought elements not normally found in the lunar regolith.

References: [1] Wilson, J. K. et al. (2012) JGR, 117, E00H23. [2] Spence, H. E. et al. (2012) Space Weather, 11, 643-650. [3] Feldman W. C. et al. (1998) Science, 281, 1496-1500. [4] Gasnault, O. et al. (2001) GRL, 28, 3797-3800. [5] Maurice, S. et al. (2004) JGR, 109, E07S04. [6] Mitrofanov, I. G. et al. (2010) Science, 330, 483-486. [7] Litvak, M. L. et al. (2012) JGR, 117, E00H22.

Wednesday, February 18, 2015

Hell Q

LROC NAC mosaic M1164853645RL, LRO orbit 23561, September 8, 2014; spacecraft and cameras slewed 3° from nadir, 33.17° angle of incidence, 71 cm resolution from 68.29 km over 33.07°S, 355.72°E [NASA/GSFC/Arizona State University].
Hell Q (3.75 km; 33°S, 355.53°E) seems younger than Tycho, standing out as it does in the nearside Southern Highlands northeast of the more famous astrobleme. 

There seems little doubt the effect of the larger, far more widespread blast zone from Tycho changed the face of this contemporary but pre-existing smaller crater. The chevron effect left grooves untouched down stream and tore away a chunk of the northeast rim, morphologies apparently perpendicular to a straight line drawn southwest to the more spectacular, 109 million year-old Tycho.

View full resolution views, of a variety of sizes, HERE.

Friday, February 13, 2015

Apollo 17 samples further refine bombardment timeline

Photomicrograph of a petrographic thin section of a piece of a coherent, crystalline impact melt breccia collected from landslide material at the base of the South Massif, Apollo 17 (sample 73217, 84). In their article published in the Feb. 12 issue of Science Advances, ASU researchers used a laser microprobe technique to investigate age relationships of three of the distinct generations of impact melt shown in this image.
Nikki Cassis
School of Earth and Space Exploration
Arizona State University

It’s been more than 40 years since astronauts returned the last Apollo samples from the moon, and since then those samples have undergone some of the most extensive and comprehensive analysis of any geological collection.

A team led by Arizona State University researchers has now refined the timeline of meteorite impacts on the moon through a pioneering application of laser microprobe technology to Apollo 17 samples.

Impact cratering is the most ubiquitous geologic process affecting the solid surfaces of planetary bodies in the solar system. The moon’s scarred surface serves as a record of meteorite bombardment that spans much of solar system history.

Developing an absolute chronology of lunar impact events is of particular interest because the moon is an important proxy for understanding the early bombardment history of Earth, which has been largely erased by plate tectonics and erosion, and because we can use the lunar impact record to infer the ages of other cratered surfaces in the inner solar system.

Researchers in ASU’s Group 18 Laboratories, headed by professor Kip Hodges, used an ultraviolet laser microprobe, attached to a high-sensitivity mass spectrometer, to analyze argon isotopes in samples returned by Apollo 17. While the technique has been applied to a large number of problems in Earth’s geochronology, this is the first time it has been applied to samples from the Apollo archive.

The samples analyzed by the ASU team are known as lunar impact melt breccias – mash-ups of glass, rock and crystal fragments that were created by impact events on the moon’s surface.

Apollo 17 sample 73217, before processing a 138.8 gm "tough impact melt" breccia rake sample from Science Station 3. The sample was half-buried near Lara crater and close to the Lee-Lincoln lobate scarp contact, and also well inside the Tycho debris chevron called Tortilla Flat. The rock contained a prominent white anorthosite clast, partially analyzed before the remainder was set aside for "posterity." Full processing has waited patiently for the 21st century. S73-16784 [NASA/JSC].
When a meteor strikes another planetary body, the impact produces very large amounts of energy – some of which goes into shock, heating and melting the target rocks. These extreme conditions can "restart the clock" for material melted during impact. As a result, the absolute ages of lunar craters are primarily determined through isotope geochronology of components of the target rocks that were shocked and heated to the point of melting, and which have since solidified.

However, lunar rocks may have experienced multiple impact events over the course of billions of years of bombardment, potentially complicating attempts to date samples and relate the results to the ages of particular impact structures.

Conventional wisdom holds that the largest impact basins on the moon were responsible for generating the vast majority of impact melts, and therefore nearly all of the samples dated must be related to the formation of those basins.

Annotated reproduction of an LROC oblique NAC mosaic showing the landing site (arrow) of the Cernan-Schmitt expedition in December 1972, a roughly 18 km-wide field of view used to illustrate "Approach to Taurus Littrow Valley," December 12, 2012 [NASA/GSFC/Arizona State University].
While it is true that enormous quantities of impact melt are generated by basin-scale impact events, recent images taken by the Lunar Reconnaissance Orbiter Camera confirm that even small craters with diameters on the order of 100 meters can generate impact melts. The team’s findings have important implications for this particular observation. The results are published in the inaugural issue of the American Association for the Advancement of Science’s newest journal, Science Advances, on Feb. 12.

“One of the samples we analyzed, 77115, records evidence for only one impact event, which may or may not be related to a basin-forming impact event. In contrast, we found that the other sample, 73217, preserves evidence for at least three impact events occurring over several hundred million years, not all of which can be related to basin-scale impacts,” says Cameron Mercer, lead author of the paper and a graduate student in ASU’s School of Earth and Space Exploration.

Apollo 17 sample 77115 was taken from the side visible above of the Science Station 7 boulder at lower left in this processed mosaic. From this vantage on the lower slopes of North Massif Gene Cernan and Harrison Schmitt had perhaps their best view across Taurus Littrow valley over to South Massif. The lunar module is easily visible at higher resolutions [NASA/JSC].
Sample 77115, collected by astronauts Gene Cernan and Harrison Schmitt at Station 7 during their third and final moonwalk, records a single melt-forming event about 3.83 billion years ago. Sample 73217, retrieved at Station 3 during the astronauts’ second moonwalk, preserves evidence for at least three distinct impact melt-forming events occurring between 3.81 billion years ago and 3.27 billion years ago. The findings suggest that a single small sample can preserve multiple generations of melt products created by impact events over the course of billions of years.

“Our results emphasize the need for care in how we analyze samples in the context of impact dating, particularly for those samples that appear to have complex, polygenetic origins. This applies to both the samples that we currently have in our lunar and meteoritic collections, as well as samples that we recover during future human and robotic space exploration missions in the inner solar system,” says Mercer.

Thursday, February 12, 2015

Postdoctoral Researcher positions, SwRI

Far-UV albedos show some agreement with epithermal neutron suppression regions [NASA/GSFC/SwRI].
Erin Rogers, PHR
Sr. Specialist
Employment Operations
Southwest Research Institute

The UV imaging spectrograph group at Southwest Research Institute (SwRI) is seeking postdoctoral planetary scientists to join our team's investigations of a variety of science questions using far-UV observations. 

Topics of study include:
  1. Characterization of volatiles within permanently shaded regions (PSRs) at the lunar poles with the Lyman Alpha Mapping Project (LAMP) imaging spectrograph on the Lunar Reconnaissance Orbiter (LRO); 
  2. Imaging Jupiter's powerful auroral emissions with the Juno UV Spectrograph (UVS)
  3. Studying the atmosphere of Pluto with the New Horizons Alice instrument
  4. Analysis of Hubble campaign observations in search of water vapor plumes on Europa
  5. Instrument development work related to the Jupiter Icy Moons Explorer (JUICE) UVS investigation and other future UV/optical projects in Astrophysics, Planetary Science, Heliophysics, and Earth Sciences.
  • Candidates are encouraged to develop their own additional research projects.

Candidates must have experience with imaging and/or spectroscopy from space-based or ground-based observatories; strong programming skills with Interactive Data Language (IDL) is preferred. A background in scientific analysis and publications related to one or more of the topics listed above is highly desirable. Specific tasks include: analyzing UV spectral imaging datasets; assist with planning future observations; publishing results in peer-reviewed journals and presentations at professional meetings; development of concepts and new technologies for UV/VIS/IR instrumentation and assist ing with flight instrument integration, test and calibration tasks, and leading and/or assisting proposal writing for new business.

All candidates must use the website to prepare and submit applications.  They may reference job number 15-01143 or utilize the following job link:

Tuesday, February 10, 2015

Can "chain of title" ever be established on the Moon?

The European Space Agency continues logistical planning for lunar habitat, a vision illustrated in a recently released online agency video presentation. Plans call for utilizing a half-buried inflatable framework eventually covered by 3D-printed and sintered regolith for improved shielding [ESA].
Douglas Jones
New York Times

Who can own Earth's Moon? Or an asteroid? Or a homestead on Mars?

According to the Outer Space Treaty of 1967, no nation can claim sovereignty over any part of any celestial rock. But the treaty is less clear on what a company or an individual can do in space — possibly because in the 1960s, the drafters of the treaty might have thought it hard to imagine a space race led by entrepreneurs rather than governments.

For companies today hoping to set up a Moon colony or to mine asteroids for platinum, the ambiguity is one more hurdle in attracting investors.

“There has been a chicken-egg conundrum to create a lunar legal framework,” said John Thornton, the chief executive of Astrobotic Technology, a Pittsburgh company that hopes to become the first private company to land a robotic spacecraft on Earth's Moon and win the Google Lunar X Prize. “How do you get businesses to invest in Earth's Moon if there is no legal framework versus how do you get a legal framework if there are no business operations?”

The Federal Aviation Administration, which licenses private space launchings in the United States, has now provided some clarity.

Read the full article, HERE.

Related Posts:
China and the Moon (June 19, 2012)

Sunday, February 8, 2015

Chang'e-5 T1 service module completes orbital tests

Weeks following the successful test of China's re-entry vehicle Xiaofei, anticipating the scheduled 2017 Chang'e-5 sample-return mission, the "T1" service module, in lunar orbit, has been put through its paces rehearsing next year's landing.
Updated, 1840 UT, 9 February

China's state news agency Xinhua reports the Chang'e-5 T1 service module in lunar orbit "has finished tests of orbiting technologies" ahead of the scheduled 2017 sample return mission.

Launched October 24, the Chang'e-5 T1 service module released its smaller passenger, the Xiaofei high-speed reentry test article, and was later steered into lunar orbit following three Lissajous circuits around L2, the semi-stable Sun-Earth-Moon second Lagrange point (L2), roughly 1.5 million km from Earth, in the direction opposite the Sun.

The interval was China's second visit to L2. After its 2011 primary mission in lunar orbit, Chang'e-2 vehicle was orbited L2 from August until the following April. The probe moved on for a very close encounter with the asteroid 4179 Toutatis, December 13, 2012.

The most celebrated part of the Chang'e-5 T1 mission was completed November 1 when, following a free-return trajectory behind the Moon the Xiaofei test article successfully returned to Earth.

Meanwhile, Xinhua reported by mid-January the T1 service module had been maneuvered to the Moon's vicinity and inserted into lunar orbit, later circularized to an altitude roughly 200 km every 127 minutes. 

"The orbiter conducted three tests between Friday and Saturday," Xinhua reported, "to modulate the speed, height and orbit, rehearing next year's Chang'e-5 sampling mission," this "according to a statement of the State Administration of Science, Technology and Industry for National Defense."

Some Related Posts:
The Chang'e-3 mission to the Moon - a special issue (January 27, 2015)
Chang'e-5 T1 service module tightens lunar orbit (January 15, 2015)
It's not bragging if you do it (December 9, 2013)

Bigelow, FAA not talking lunar property rights

Notional Bigelow inflatable lunar habitat - Detail of scale model of a possible lunar habitat, based on Bigelow Aerospace inflatable modules. Recent exchanges of reports with the FAA, U.S. authority for American compliance with the 1967 Outer Space Treaty, have been misinterpreted as clearing the path for land claims on the Moon [Bigelow].
Jeff Foust

A positive review by the Federal Aviation Administration of a proposed Bigelow Aerospace lunar habitat is seen as a first step towards supporting commercial activities on the moon, but contrary to some reports, that review does not represent a government endorsement of property rights claims there.

In a December 22 letter to Bigelow Aerospace, the FAA’s Office of Commercial Space Transportation (AST) said it had completed a payload review of a proposed lunar habitat requested by the company in late 2013. The office, working with several other government agencies, said it was willing to use its authority to ensure Bigelow could carry out its activities there without interference from other companies licensed by the FAA.

“AST was able to assure Bigelow Aerospace that it in fact would use its launch licensing authority, as best it can, to protect private sector assets on the Moon and to provide a safe environment for companies to conduct peaceful commercial activities without fear of harmful interference from other AST licensees,” Mike Gold, director of Washington operations and business growth for Bigelow Aerospace, said in a Feb. 3 statement to SpaceNews.
First reported by Reuters February 3, news was interpreted by many as an endorsement by the U.S. government of lunar property rights for private companies. Nield said that was not the intent of the FAA’s review.
Although Bigelow has no immediate plans for a lunar base, the company requested the payload review — one part of the FAA’s overall launch licensing process — to identify any issues that could hinder private development of the moon. Bigelow decided to pursue the review after completing a report for NASA in 2013 that identified an uncertain regulatory environment as a major obstacle to commercial activities there.

“We think that, first of all, this is not an overnight process, and that is probably the main reason why we are starting on this,” Bigelow Aerospace founder and president Robert Bigelow said at a November 2013 press conference, discussing the company’s intent to request the payload review.

“They wanted to know, before they go through a lot of engineering design, analysis, and investment, whether there were going to be any showstoppers,” said George Nield, FAA associate administrator for commercial space transportation, at the FAA Commercial Space Transportation Conference here February 4.

“In this particular case, it looked like a really good idea that the government as a whole is supportive of,” Nield added.

“We’re not talking about property rights at this point,” he said. “What we’re talking about is having the U.S. government have a regulatory framework that provides some certainty so they will be free to proceed with their plans and raising of funds.”

Read the full article at SpaceNews, HERE.

Some Related Posts:
"The Flight of the Dragon" Paul Spudis (May 16, 2012)
Boeing, Bigelow commercial crew concept Rob Coppinger (February 2, 2010)
Boeing throws hat in with Bigelow (September 23, 2009)

Armstrong's treasure of Apollo 11 artifacts found

Neil Armstrong's "McDivitt Bag," filled with priceless souvenirs of the July 1969 first manned expedition to the lunar surface, has been disclosed to the Smithsonian Institute by his widow. Among them, the 16mm DAC camera that captured the landing from the starboard window.
Jesus Diaz

These are the contents of a mysterious white bag found hidden in Neil Armstrong's closet: Weird looking lamps, wrenches, utility brackets, sights, and a film camera that later was identified as the one that captured the famous Apollo 11's descent on the Moon's surface. Nobody knew about it, including his widow.

According to NASA, Carol Armstrong sent photos to Allan Needell, curator of the Apollo collection at the Smithsonian's National Air and Space Museum, who immediately knew what was inside: It was a McDivitt Purse full of parts from the Eagle, Apollo 11's Lunar Module:

After Neil Armstrong's death, his widow, Carol, discovered a white cloth bag in a closet, containing what were obviously either flight or space related artifacts. She contacted Allan Needell, curator of the Apollo collection at the Smithsonian's National Air and Space Museum, and provided photographs of the items. Needell, who immediately realized that the bag—known to the astronauts as the Purse - and its contents could be hardware from the Apollo 11 mission, asked the authors for support in identifying and documenting the flight history and purpose of these artifacts. After some research it became apparent that the purse and its contents were lunar surface equipment carried in the Lunar Module Eagle during the epic journey of Apollo 11.

These artifacts are among the very few Apollo 11 flown items brought back from Tranquility Base and, thus, are of priceless historical value. Of utmost importance is the 16mm movie camera with its 10mm lens.

The on-board 16 mm film camera, with which the landing, first steps, and take off of the lunar module Eagle from Mare Tranquillitatis were filmed, has been unearthed in a bag of similarly priceless small artifacts of the epic mission found in Neil Armstrong's closet in Ohio.
The camera was mounted behind the right forward window of the lunar module and was used to film the final phase of the descent to the lunar surface, the landing, as well as Neil Armstrong's and Buzz Aldrin's activities on the lunar surface including taking the first samples of lunar soil and planting the US flag.

Still from the Apollo 11 16mm DAC film camera shows Armstrong (with visor up) taking his initial, halting steps out onto Mare Tranquillitatis, still tethered to the spacecraft.
Thanks to the Neil Armstrong family, the Apollo 11 purse and its contents are now on loan at the National Air and Space Museum for preservation, research and eventual public display.

Here's a list of everything inside and how it looked inside and outside the Eagle:

Read the full article at sploid.gizmodo, HERE.

Wednesday, February 4, 2015

Hydrogen retention on pole-facing slopes

Lovelace (57.06 km; 82.08°N, 250.49°E) crater, of the Moon's far north, hosts a signature of volatiles within permanently shadowed regions (PSR) on the inside slope of its south wall. Long-term studies of the Moon's reserves of hydrogen and other volatiles, made possible by the extended science missions of the Lunar Reconnaissance Orbiter (LRO), show a diurnal cycle of hydrogen retention on pole-facing slopes, perhaps a result of neutral hydrogen from the Sun. [NASA/GSFC/ASU/LOLA/PDS].
Bill Steigerwald
Goddard Space Flight Center

Space travel is difficult and expensive – it would cost thousands of dollars to launch a bottle of water to the moon. The recent discovery of hydrogen-bearing molecules, possibly including water, on the Moon has explorers excited because these deposits could be mined if they are sufficiently abundant, sparing the considerable expense of bringing water from Earth.

Lunar water could be used for drinking or its components – hydrogen and oxygen – could be used to manufacture important products on the surface that future visitors to the moon will need, like rocket fuel and breathable air.

Recent observations by NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft indicate these deposits may be slightly more abundant on crater slopes in the southern hemisphere that face the lunar South Pole.

"There’s an average of about 23 parts-per-million-by-weight (ppmw) more hydrogen on Pole-Facing Slopes (PFS) than on Equator-Facing Slopes (EFS)," said Timothy McClanahan of NASA's Goddard Space Flight Center.

This is the first time a widespread geochemical difference in hydrogen abundance between PFS and EFS on the moon has been detected. It is equal to a one-percent difference in the neutron signal detected by LRO's Lunar Exploration Neutron Detector (LEND) instrument. McClanahan is lead author of a paper about this research published online October 19 in the journal Icarus.

The hydrogen-bearing material is volatile (easily vaporized), and may be in the form of water molecules (two hydrogen atoms bound to an oxygen atom) or hydroxyl molecules (an oxygen bound to a hydrogen) that are loosely bound to the lunar surface. The cause of the discrepancy between PFS and EFS may be similar to how the Sun mobilizes or redistributes frozen water from warmer to colder places on the surface of the Earth, according to McClanahan.

"Here in the northern hemisphere, if you go outside on a sunny day after a snowfall, you'll notice that there's more snow on north-facing slopes because they lose water at slower rates than the more sunlit south-facing slopes" said McClanahan. "We think a similar phenomenon is happening with the volatiles on the moon – PFS don't get as much sunlight as EFS, so this easily vaporized material stays longer and possibly accumulates to a greater extent on PFS."

The team observed the greater hydrogen abundance on PFS in the topography of the moon's southern hemisphere, beginning at between 50 and 60 degrees south latitude.

The Moon's polar south and its neutron suppression zpmes, indicative of the presence of hydrogen (inside and outside permanent shadow) mapped from data collected from the LRO LEND instrument over two and a half years [NASA/GSFC/SVS/Pockocmoc].
Slopes closer to the South Pole show a larger hydrogen concentration difference. Also, hydrogen was detected in greater concentrations on the larger PFS, about 45 ppmw near the poles. Spatially broader slopes provide more detectable signals than smaller slopes. The result indicates that PFS have greater hydrogen concentrations than their surrounding regions. Also, the LEND measurements over the larger EFS don't contrast with their surrounding regions, which indicates EFS have hydrogen concentrations that are equal to their surroundings, according to McClanahan. The team thinks more hydrogen may be found on PFS in northern hemisphere craters as well, but they are still gathering and analyzing LEND data for this region.

There are different possible sources for the hydrogen on the moon. Comets and some asteroids contain large amounts of water, and impacts by these objects may bring hydrogen to the moon. Hydrogen-bearing molecules could also be created on the lunar surface by interaction with the solar wind. The solar wind is a thin stream of gas that's constantly blown off the Sun. Most of it is hydrogen, and this hydrogen may interact with oxygen in silicate rock and dust on the moon to form hydroxyl and possibly water molecules. After these molecules arrive at the moon, it is thought they get energized by sunlight and then bounce across the lunar surface; and they get stuck, at least temporarily, in colder and more shadowy areas.

Since the 1960's scientists thought that only in permanently shadowed areas in craters near the lunar poles was it cold enough to accumulate this volatile material, but recent observations by a number of spacecraft, including LRO, suggest that hydrogen on the moon is more widespread.

It's uncertain if the hydrogen is abundant enough to economically mine. "The amounts we are detecting are still drier than the driest desert on Earth," said McClanahan. However, the resolution of the LEND instrument is greater than the size of most PFS, so smaller PFS slopes, perhaps approaching yards in size, may have significantly higher abundances, and indications are that the greatest hydrogen concentrations are within the permanently shaded regions, according to McClanahan.

The team made the observations using LRO's LEND instrument, which detects hydrogen by counting the number of subatomic particles called neutrons flying off the lunar surface. The neutrons are produced when the lunar surface gets bombarded by cosmic rays. Space is permeated by cosmic rays, which are high-speed particles produced by powerful events like flares on the Sun or exploding stars in deep space. Cosmic rays shatter atoms in material near the lunar surface, generating neutrons that bounce from atom to atom like a billiard ball. Some neutrons happen to bounce back into space where they can be counted by neutron detectors.

Neutrons from cosmic ray collisions have a wide range of speeds, and hydrogen atoms are most efficient at stopping neutrons in their medium speed range, called epithermal neutrons. Collisions with hydrogen atoms in the lunar regolith reduce the numbers of epithermal neutrons that fly into space. The more hydrogen present, the fewer epithermal neutrons the LEND detector will count.

Neutron suppression information in the Moon's polar north is, as yet, less granular than data mapped in greater detail over the far South. Here neutron suppression is overlaid on a LROC WAC mosaic with permanently shadowed regions (PSRs) outlined in black. Again, the occurrence of hydrogen is related to sunlight but not necessarily tied to its total absence.
The team interpreted a widespread decrease in the number of epithermal neutrons detected by LEND as a signal that hydrogen is present on PFS. They combined data from LEND with lunar topography and illumination maps derived from LRO's LOLA instrument (Lunar Orbiter Laser Altimeter), and temperature maps from LRO's Diviner instrument (Diviner Lunar Radiometer Experiment) to discover the greater hydrogen abundance and associated surface conditions on PFS.

In addition to seeing if the same pattern exists in the moon's northern hemisphere, the team wants to see if the hydrogen abundance changes with the transition from day to night. If so, it would substantiate existing evidence of a very active production and cycling of hydrogen on the lunar surface, according to McClanahan.

The research was funded by NASA's LRO mission. LEND was supplied by the Russian Federal Space Agency Roscosmos. Launched on June 18, 2009, LRO has collected a treasure trove of data with its seven powerful instruments, making an invaluable contribution to our knowledge about the moon. LRO is managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland, for the Science Mission Directorate at NASA Headquarters in Washington.

Monday, February 2, 2015

LRO could remain in present orbit 7 or more years

Because the Moon is lumpy and uneven, it's possible nothing has ever been in close-orbit around our companion planet as long as the Lunar Reconnaissance Orbiter. Certainly nothing built by humans. Few deep space missions have delivered as much return on their investment. The sheer volume of data returned by LRO exceeds all deep space missions ever launched combined, several times over [NASA/GSFC/SVS].


Noah E. Petro and John W. Keller
NASA Goddard Space Flight Center
Solar System Exploration Division

The Lunar Reconnaissance Orbiter (LRO) has been orbiting the Moon for over five years. In that time, data from the seven instruments onboard the spacecraft have made significant advances in our understanding of the Moon and its environment. In September 2014 LRO completed its first Extended Science Mission (ESM) and began a second ESM (ESM2). 

During the both ESM and ESM2, LRO has been in a quasi-stable, eccentric orbit of ~40 x 180 km with a periapse near the South Pole (Figure 1). This orbit enables high resolution measurements around the South Pole. 

The LRO Project is considering a maneuver in early 2015 to lower the periapse in order to further improve measurements over the South Pole, particularly by the LOLA instrument. Based on the current annual consumption of fuel, the spacecraft could remain in its current orbit for at least 7 more years.

FIGURE 1. Orbital history of LRO since arriving at the Moon in 2009. LRO now employs yearly station keeping (SK) maneuvers in order to maintain its orbit. There are also periodic momentum unload burns that use small quantities of fuel.
LRO Operations: As part of the approval for continued operations, LRO was directed by NASA HQ to terminate operations of the Mini-RF instrument. All of LRO’s remaining six instruments are operating nominally, and have experienced no significant degradation since beginning the ESM over two years ago.

During extended operations the LRO spacecraft has performed exceptionally well, with 98.4% uptime during the life of the mission. LRO retains sufficient fuel quantities so that its current orbit could be maintained for at least 8 years, if not longer.

LRO Science In ESM2: An overarching theme of ESM2 for LRO is that of change. A number of measurements have shown changes to the lunar surface and to its environment. LRO will focus on the five following themes that each build on prior observations from LRO, LADEE, GRAIL, and the Moon Mineralogy Mapper. Each theme has numerous questions that are address, an example few are given here.
  1. Transport of Volatiles. How are volatile elements and compounds distributed, transported, and sequestered?
  2. Contemporary Surface Change. What causes changes in the flux and intensities of meteoroid impacts onto terrestrial planets.
  3. Regolith Evolution. Characterize planetary surfaces to understand how they are modified by geologic processes.
  4. Probing the Interior from Observations of the Surface. Characterize planetary interiors to understand how they differentiate and evolve from their initial state
  5. Interactions with the Space Environment.  How is surface material modified exogenically? How do exospheres form, evolve, and interact with the space environment?
LRO Data: The LRO instrument teams will continue to deliver data to the PDS every three months. As of the beginning of 2015 over 575 Tb of data have been placed into the PDS [1]. This data volume contains a range of products, including higher level maps, mosaics, and derived products. The PDS has made available the Lunar Orbital Data Explorer [2], a mapbased tool to search for finding and downloading PDS science data of LRO as well as other recent lunar missions.

In addition to the PDS holdings, several of the LRO instrument teams have additional products and tools available on their websites (Table 1).

Several global map products have recently been added to the PDS, here we highlight a few that are new in the last year. The Mini-RF team has assembled a global mosaic of their monostatic measurements [3].

For the first time we have global radar data for the Moon, data that clearly shows variations in rock abundance and surface texture over both the near and farside (Figure 2).

FIGURE 2. Mini-RF global mosaic of the Circular Polarization Ratio (CPR), one of the number of Mini-RF mosaic products now available online.
The LROC team regularly adds new products to the PDS via the team webpage (Table 1), including shapefiles, global mosaics, NAC-derived DEM’s, and NAC mosaics of selected targets. Recently the LROC team has made available a number of anaglyphs (Figure 3) showcasing the ability of the LRO spacecraft and the LROC team to precisely target the NACs.

FIGURE 3. Red-Blue anaglyph of the central peak of Euler crater.  The LROC team has made a number of anaglyphs available on their website (Table 1).
The LAMP team has a number of polar products available, including FUV ratio maps of both poles (Figure 4). These following maps are available at a resolution of 240 meters per pixel; Lyman-α (119.57–125.57 nm), Long (130–190 nm), On-band (130–155 nm), Off-band (155–190 nm), H2O Absorption Feature Depth Maps made by a Ratio map of on/off band.

FIGURE 4. LAMP Lyman-α map of the South Pole. LRO has focused on volatiles at the South Pole since arriving at the Moon 5+ years ago.
Table 1. LRO teams and their websites

LRO Project









Use LRO Data!

The LRO Project has begun holding a series of data users workshops with the goal of helping the community work with the large volume of LRO data. Presentations given at the workshops are archived at the LRO website [4]. Questions regarding the access and use of LRO data can be directed to the authors of this abstract.

References:  [1] LRO PDS Archive, (
[2] Lunar Orbital Data Explorer, (
[3] Cahill, J. T. S., et al., (2014) Icarus, 243, 173-190.
[4] LRO Data Resources, (