Thursday, October 30, 2014

High speed re-entry of test platform expected Nov. 1

The lunar north pole and about 60 percent of the Moon's farside is visible in this view captured from 3300 km over the Moon's farside, Oct. 28, from the solar array camera in flight aboard a Chang'e 5 flight dynamic test platform. From Earth, a low Crescent Moon was visible in the evening sky. The phase angles of this image are comparable with those of the Soviet Union's Luna 3 vehicle and its first photographs of the farside captured October 7, 1959. Now well along on the return trip, a challenging re-entry at above 11 km/second, a first for China and the primary reason for the test mission, will occur Nov. 1, according to the State Administration of Science, Technology and Industry for National Defense (SASTIND). Dynamic control and high-speed re-entry technologies are necessary for the success of the scheduled 2017 robotic sample return mission Chang'e 5 [Xinhua].

Comparisons have been made with the incidence angles of this, mankind's first look at the Moon's farside, from the Soviet Union's unmanned Luna 3, October 7, 1959 and the view above of Moon and Earth together from the Chang'e-5 flight dynamics test platform, October 28, 2014. More of the Moon's nearside and less farside was seen in the 1959 facsimile radioed back to Earth, but both views feature prominently Mare Moscoviense and mare-filled Tsiolkovskiy crater and highlight the now-well known differences between the two hemispheres, tidally locked into their permanent relationships with earthbound viewers [MAS/NASA].

Postdoctoral position in lunar magnetism

Data from the Apollo era and Lunar Prospector (1998-1999) is being augmented with more recent data from Kaguya (2007) and especially LADEE (2014) to create a more comprehensive model of the long-established connection between crustal magnetism at the antipodes of the Moon's youngest basins and the anomalously fresh surface materials found at these points, built up into brighter, sometimes beautiful swirl formations. (Animation from lunar crustal thickness maps from GRAIL (2012) by the Science Visualization Studio at the Goddard Space Flight Center [NASA/GSFC].
The Institut de Physique du Globe de Paris (IPGP) is inviting applications for a postdoctoral position in the broad field of lunar magnetism. This one-year position (renewable for a second year) aims to decipher the origin of crustal magnetism by modeling spacecraft-derived magnetic field data.

Potential research projects include modeling the direction of crustal magnetization, comparisons of derived crustal magnetization with measured properties of lunar samples, and correlations between magnetic anomalies and GRAIL gravity. 

As part of a larger project, the applicant will have the opportunity to collaborate with paleomagneticists at CEREGE (Aix en Provence) and geodynamo modelers at ISTerre (Grenoble).

To apply, please provide a CV, publication list, contact information of two references, and a 2-page letter that motivates the applicant's interest in the topic and that describes prior relevant research experience. Please respond by email to Mark Wieczorek ( before March 23, 2015.

Mark Wieczorek
IPGP Planetary and Space Sciences
University of Sorbonne
Paris Cité
Tel: +33 (0)1 57 27 53 08

Wednesday, October 29, 2014

LADEE impact crater found

LADEE impact site on the eastern rim of Sundman V crater, the spacecraft was heading west when it impacted the surface. The image was created by ratioing two images, one taken before the impact and another after the impact. The bright area shows the impact point and the ejecta (things that have changed between the time of the two images). The ejecta form a V shaped pattern extending to the northwest from the impact point. Ratio constructed with LROC images M1163066820RE and M1101816767RE [NASA/GSFC/Arizona State University].
Mark Robinson
Principal Investigator
Lunar Reconnaissance Orbiter Camera (LROC)
Arizona State University

The Lunar Atmosphere and Dust Environment Explorer (LADEE) was launched from Wallops Island on 6 September 2013 at 11:27 EDT and was visible over much of the eastern coast of the United States. The spacecraft was 2.37 m (7.8 ft) high and 1.85 m (6.1 ft) wide with a mass of 383 kg (844 lb) including the fuel.

After expending most of its fuel during its successful exploration of the Moon the spacecraft had a mass of about only 248 kg (547 lb) when it impacted the surface.

Artist's rendition of the LADEE spacecraft in orbit around the Moon [NASA/JAXA/LP].
Originally LADEE was placed into a retrograde, near-equatorial orbit to study the Moon's surface bound exosphere and dust environment. Since the Apollo era of exploration several conflicting ideas and observations concerning the existence (or not) of near-surface and high altitude dust were debated, and thus one of LADEE’s key science goals was to search for dust particles high above the surface (no dust was found).

LADEE's engines were fired on 11 April 2014 to adjust the orbit in such a way as to guarantee a farside impact if the spacecraft did not survive the 15 April 2014 eclipse. There was a small worry that if the spacecraft failed during the eclipse and was uncontrollable, it might impact near one of the Apollo sites. Over the subsequent 7 days, the low point in LADEE's orbit decreased resulting in an impact on 18 April 2014.

Before and after images of the LADEE impact site [NASA/GSFC/Arizona State University].
As it passed over the western limb as seen from the Earth, the spacecraft impacted the eastern rim of Sundman V crater (11.85°N, 266.75°E). The impact site (11.8494°N, 266.7507°E) is about 780 m from the crater rim with an altitude of about 2590 m, and was only about 295 meters north of its originally predicted location (based on tracking data).

Like the LADEE spacecraft, the impact crater is small, greater than 3 meters in diameter, barely resolvable by the LROC NAC. Based on impact models, a crater of only about 1.8 m (6 ft) diameter is expected. The crater is very small because, as impacts go, LADEE had a low mass and a low density (0.43 g / cm3 vs. larger than 3.0 g / cm3 for an ordinary chondrite meteorite), and was traveling at only a tenth the speed (1699 m/sec - 3800 mph) of an average asteroid.

LADEE impact crater (centered of image) has a distinctive hour-glass albedo pattern indicative of low angle impacts. Bright material extends to the northwest, while only a minor amount was ejected to the southeast; NAC M1163066820RE [NASA/GSFC/Arizona State University].
Because it is so small, the crater is hard to identify among the myriad of small fresh craters that dot the lunar surface. However, as images had been acquired of the impact region before the impact occurred, they could be compared with images acquired after the impact to identify the crater.

Since NAC images are so large (250 megapixels) and the new crater is so small the LROC team coregistered the before and after images (called a temporal pair) and then divided the after image by the before image. In this manner any changes to the surface stick out like a beacon! For the LADEE crater the ejecta forms a triangular pattern primarily downrange (to the west) extending more than 200 meters from the impact site. There is also a small triangular area of ejecta uprange but it extends only about 20-30 meters. The ejecta pattern is oriented WNW consistent with the direction the spacecraft was traveling when it impacted.

Zoomed-in view of the impact site, image is 200 m across, NAC M1163066820RE [NASA/GSFC/Arizona State University].
Explore the catalog of LROC close-ups of lunar spacecraft landing and impact sites, HERE.

Related LADEE Posts:
First Science from LADEE (45th LPSC, March 18 2014)
LADEE's (star tracker) images of the Moon (February 14, 2014)
LADEE economy adds 28 days to mission (February 5, 2014)
LROC captures LADEE from 9,000 meters (January 30, 2014)
Red Moon, Blue Moon Dwayne DayThe Space Review (December 3, 2013)
LADEE begins collecting data (November 22, 2013)
LADEE transitioning out of commissioning phase (November 6, 2013)
Apollo 12 ALSEP first to measure dust accumulation (November 21, 2013)
Chang'e-3 & LADEE: The Role of Serendipity (October 31, 2013)
LADEE LLCD sets new data record (October 25, 2013)
Measuring almost nothing, looking for the almost invisible (October 16, 2013)
LADEE legacies (September 7, 2013)
LADEE Prelaunch Mission Briefing (September 6, 2013)
ESA prepares for LADEE (July 31, 2013)
LADEE arrives at Wallops Island (June 5, 2013)
LADEE ready to baseline dusty lunar exosphere (June 5, 2013)
First laser comm system ready for launch on LADEE (March 16, 2013)
LADEE project manager update (February 6, 2013)
The Mona Lisa test for LADEE communications (January 21, 2013)
Toxicity of lunar dust (July 2, 2012)
Expectations for the LADEE LDEX (March 23, 2012)
The Dust Management Project (August 9, 2010)
LADEE architecture and mission design (July 6, 2010)
DesertRatS testing electrodynamic dust shield (July 5, 2010)
Dust transport and its importance in the origin of lunar swirls (February 21, 2010)
Dust accumulation on Apollo laser reflectors may indicate a surprisingly fast and
more dynamic lunar exosphere
 (February 16, 2010)
NASA applies low cost lessons to LADEE (January 18, 2010)
Nanotech advances in lunar dust mitigation (August 19, 2009)
Moon dust hazard influenced by Sun's elevation (April 17, 2009)
LADEE launch by Orbital from Wallops Island (April 14, 2009)
Understanding the activation and solution properties of lunar dust
for future lunar habitation
 (March 2, 2009)
Respiratory toxicity of lunar highland dust (January 19, 2009)
Toxicological effects of moon dust (June 25, 2008)
Moon dust and duct tape (April 22, 2008)

Friday, October 24, 2014

Bellcomm’s 1968 Lunar Exploration Program

Apollo 15 astronaut James Irwin works beside the mission’s Lunar Roving Vehicle, the first to reach the moon, July 31, 1971. Beginning with Apollo 15, NASA deviated from Bellcomm’s proposed Lunar Exploration Program outlined in 1968 [NASA].
David S. F. Portree

Bellcomm, Inc., based near NASA Headquarters in Washington, DC, was carved out of Bell Labs in 1962 to provide technical advice to NASA’s Apollo Program Director. The organization rapidly expanded its bailiwick to support nearly all NASA Office of Manned Space Flight advance planning.

In a January 1968 report, Bellcomm planners N. Hinners, D. James, and F. Schmidt proposed a mission series designed to fill a gap which they felt existed in NASA’s lunar exploration schedule between the first piloted Apollo lunar landing and later, more advanced Apollo Applications Program (AAP) lunar flights. The trio declared that their plan was “based upon a reasonable set of assumptions regarding hardware capability and evolution, an increase in scientific endeavor, launch rates, budgetary constraints, operational learning, lead times, and interaction with other space programs,” as well as “the assumption that lunar exploration will be a continuing aspect of human endeavor.”

To bridge the gap between early Apollo and AAP, they envisioned a series of 12 lunar missions in four phases.

Read the full article, HERE.

Thursday, October 23, 2014

China launches lunar sample return test mission

Long March 3C lofts a lunar free-return trajectory and re-entry test module toward cislunar space early Friday morning, October 24, local time. The booster lifted off from Xichang Satellite Launch Center, in China's Sichuan Province, beginning a nine-day mission to 'live fire' test technologies China considers vital to the eventual success of Chang'e-5, a robotic lunar sample return mission now planned for 2017 [Xinhua/Jiang Hongjing].
Test module launch  preparations [CNSA/CLEP].
XICHANG, Sichuan, Oct. 24 (Xinhua) -- China launched an unmanned spacecraft early Friday to test technologies to be used in the Chang'e-5, a future probe that will conduct the country's first moon mission with a return to Earth.

The lunar orbiter was launched atop an advanced Long March-3C rocket from the Xichang Satellite Launch Center in southwest China's Sichuan Province.

The test spacecraft separated from its carrier rocket and entered the expected the orbit shortly after the liftoff, according to the State Administration of Science, Technology and Industry for National Defense.

The whole mission will take about eight days. Developed by China Aerospace Science and Technology Corporation, the spacecraft will fly around the moon for half a circle and return to Earth.

On its return, the test spacecraft will approach the terrestrial atmosphere at a velocity of nearly 11.2 kilometers per second and rebound to slow down before re-entering the atmosphere. It will land in north China's Inner Mongolia Autonomous Region.

The mission is to obtain experimental data and validate re-entry technologies such as guidance, navigation and control, heat shield and trajectory design for a future touch-down on the moon by Chang'e-5, which is expected to be sent to the moon, collect samples and return to Earth in 2017.

It is the first time China has conducted a test involving a half-orbiter around the moon at a height of 380,000 kilometers before having the spacecraft return to Earth.

The test orbiter is a precursor to the last phase of a three-step moon probe project, a lunar sample return mission.

China carried out Chang'e-1 and Chang'e-2 missions in 2007 and 2010, respectively, capping the orbital phase.

The ongoing second phase saw Chang'e-3 with the country's first moon rover Yutu onboard succeed in soft landing on the moon in December 2013. Chang'e-4 is the backup probe of Chang'e-3 and will help pave the way for future probes.

Related Posts:
Geologic characteristics: Chang'E-3 exploration region (January 31, 2014)
ESA on Yutu, as controllers wait for sunrise, February 9 (January 31, 2014)
Problem with solar-powered Yutu rover before nightfall (January 25, 2014)
Chang'e begins long-term science mission (January 18, 2014)
Preliminary Science Results from Chang'e-3 (January 16, 2014)
Chang'e-3 and Yutu survive first lunar night (January 14, 2014)
Chang'e-3 APXS delivers its first surface analysis (January 1, 2014)
Chang'e-3 lander and Yutu rover from LRO (December 31, 2013)
6 of 8 Chang'e-3 science instruments now active (December 18, 2013)
LRO: Finding Chang'e-3 (December 15, 2013)
China's Jade Rabbit, it's time in the Sun (December 15, 2013)
Chang'e-3 Landing Site in Mare Imbrium (December 15, 2013)
Jade Rabbit successfully deployed to the lunar surface (December 14, 2013)
It's not bragging if you do it (December 9, 2013)
"Lunar Aspirations" - Beijing Review (December 9, 2013)
Chang'e-3 safely inserted into lunar orbit (December 6, 2013)
CCTV: Chang'e-3, launch past TLO to Earthview (December 2, 2013)
Chang'e-3 launched from Xichang (December 1, 2013)
Chang'e-3 launch window opens 1 December 1730 UT (November 29, 2013)
Helping China to the MoonESA (November 29, 2013)
Chang'e-3 and LADEE: The Role of Serendipity (October 31, 2013)
Outstanding animation celebrates China's Chang'e-3 (October 29, 2013)
LROC updates image tally of human artifacts on the Moon (September 25, 2013)
Chang'e-3: China's rover mission (May 4, 2013)
China's grand plan for lunar exploration (October 11, 2012)
ILOA to study deep space from Chang'e-3 (September 11, 2012)
China's Long March to the Moon (January 14, 2012)
China plans lunar research base (May 11, 2011)
PRC continues methodical program (March 8, 2011)
Chang'e-2 arrives in mission orbit (October 9, 2010)
Dispatch from Chang'e-2: Sinus Iridum (October 4, 2010)
Chang'e-2 takes direct approach (October 1, 2010)
Chang'e-2 sets stage for future lunar missions (September 3, 2010)
Chang'e-1 research reported published (July 22, 2010)

China to launch sample return re-entry test vehicle

Long March 3C at Xichang [CNSA/CLEP].
Mo Hong'e

China will launch a new lunar mission this week to test technology likely to be used in Chang'e-5, a future lunar probe with the ability to return to Earth.

The experimental spacecraft launched this week is expected to utilize a free-return trajectory to fly high over the Moon's farside and adjust its course for return directly to Earth, according to a source with the State Administration of Science, Technology and Industry for National Defense.

The test module is reportedly in nominal condition and is scheduled to launch sometime prior to local dawn, between Friday and Sunday, from the Xichang Satellite Launch Center.

China's Long March-3C booster will carry the mission through trans-lunar injection.

The mission will involve the spacecraft cislunar navigation, re-entering Earth's atmosphere at above 11 km per second and landing safely on Earth, the source said.

Testing the spacecraft to return land safely at a pre-determined location is considered to be a key capability needed for Chang'e-5, the 2017 mission  designed to land, retrieve lunar samples, launch from the Moon and return the samples to Earth.

Monday, October 13, 2014

LRO: widespread evidence of young lunar volcanism

The feature called Maskelyne is one of many newly discovered young volcanic deposits on the Moon. Called irregular mare patches, these areas are thought to be remnants of small basaltic eruptions that occurred much later than the commonly accepted end of lunar volcanism, 1 to 1.5 billion years ago [NASA/GSFC/Arizona State University].
Dwayne Brown

NASA’s Lunar Reconnaissance Orbiter (LRO) has provided researchers strong evidence the moon’s volcanic activity slowed gradually instead of stopping abruptly a billion years ago.

Scores of distinctive rock deposits observed by LRO are estimated to be less than 100 million years old. This time period corresponds to Earth’s Cretaceous period, the heyday of dinosaurs. Some areas may be less than 50 million years old. Details of the study are published online in Sunday’s edition of Nature Geoscience.

“This finding is the kind of science that is literally going to make geologists rewrite the textbooks about the moon,” said John Keller, LRO project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

The deposits are scattered across the moon’s dark volcanic plains and are characterized by a mixture of smooth, rounded, shallow mounds next to patches of rough, blocky terrain. Because of this combination of textures, the researchers refer to these unusual areas as irregular mare patches.

The features are too small to be seen from Earth, averaging less than a third of a mile (500 meters) across in their largest dimension. One of the largest, a well-studied area called Ina, was imaged from lunar orbit by Apollo 15 astronauts.

Ina appeared to be a one-of-a-kind feature until researchers from Arizona State University in Tempe and Westfälische Wilhelms-Universität Münster in Germany spotted many similar regions in high-resolution images taken by the two Narrow Angle Cameras that are part of the Lunar Reconnaissance Orbiter Camera, or LROC. The team identified a total of 70 irregular mare patches on the near side of the moon.

The large number of these features and their wide distribution strongly suggest that late-stage volcanic activity was not an anomaly but an important part of the moon's geologic history.

The numbers and sizes of the craters within these areas indicate the deposits are relatively recent. Based on a technique that links such crater measurements to the ages of Apollo and Luna samples, three of the irregular mare patches are thought to be less than 100 million years old, and perhaps less than 50 million years old in the case of Ina. The steep slopes leading down from the smooth rock layers to the rough terrain are consistent with the young age estimates.

In contrast, the volcanic plains surrounding these distinctive regions are attributed to volcanic activity that started about 3 1/2 billion years ago and ended roughly 1 billion years ago. At that point, all volcanic activity on the moon was thought to cease.

Several earlier studies suggested that Ina was quite young and might have formed due to localized volcanic activity. However, in the absence of other similar features, Ina was not considered an indication of widespread volcanism.

The findings have major implications for how warm the moon’s interior is thought to be.

An oblique, novel view of the Ina formation (3 km across, 18.65°N, 5.3°E) from the LROC narrow angle camera (resolution 2.5 meters per pixel [NASA/GSFC/Arizona State University].
“The existence and age of the irregular mare patches tell us that the lunar mantle had to remain hot enough to provide magma for the small-volume eruptions that created these unusual young features,” said Sarah Braden, a recent Arizona State University graduate and the lead author of the study.

The new information is hard to reconcile with what currently is thought about the temperature of the interior of the moon.

“These young volcanic features are prime targets for future exploration, both robotic and human,” said Mark Robinson, LROC principal investigator at Arizona State University.

LRO is managed by Goddard for NASA’s Science Mission Directorate at NASA Headquarters in Washington. LROC, a system of three cameras, was designed and built by Malin Space Science Systems and is operated by Arizona State University.

To access the complete collection of LROC images, visit

For more information about LRO, visit

Some Related Posts:
Hansteen α -   January 15, 2014
Small-scale volcanism on the lunar mare, July 13, 2013
Unassuming volcanic vent north of Aristarchus Plateau, April 1, 2013
New views of the hollows of Rimae Sosigenes, March 28, 2013
Inside Rima Hyginus, June 12, 2012
Ina of the Meniscus Hollows, March 21, 2012
LUNAR MENISCUS HOLLOWS. P. J. Stooke, Department of Geography and Centre for Planetary Science and Exploration, University of Western Ontario, London, Ontario, Canada; 43rd Lunar and Planetary Science Conference (2012), #1011.
Whale of a Hollow, March 20, 2012
It's a gas, man, Paul Spudis, Smithsonian Air & Space, October 6, 2011

Sunday, October 12, 2014

New evidence for young lunar volcanism

One of many newly-discovered young volcanic deposits on the Moon (4.330°N, 33.750°E), this example is near the crater Maskelyne, in south central Mare Tranquillitatis. Illustration from from "New evidence for young lunar volcanism," Mark Robinson, Oct. 12, 2014. LROC NAC observation M1123340138R, LRO orbit 17730, May 16, 2013; slew 3° from orbital nadir, incidence 66.55° resolution 1.04 meters from 102.5 km over 4.26°N, 33.97°E [NASA/GSFC/Arizona State University].
Mark Robinson
Principal Investigator
Lunar Reconnaissance Orbiter Camera (LROC)
Arizona State University

Many young volcanic deposits were recently identified in LROC NAC images. Their sharp nature and general lack of superposed impact craters greater than 20 meters in diameter indicate these deposits probably formed in the last 100 million years, perhaps even more recently than 50 million years ago. An amazing result!

A new paper, (Evidence for basaltic volcanism on the Moon within the past 100 million years, Nature Geoscience 7, 787-791; 2014) presents 70 topographic anomalies, informally called Irregular Mare Patches, or IMPs, most of these occurrences were previously undocumented. The IMPs are thought to be remnants of small basaltic eruptions that formed significantly after the commonly accepted end of lunar volcanism (1 to 1.5 billion years ago).

Locations of IMPs. Red circles indicate either a single IMP greater than 100 meters in diameter, or a cluster of smaller IMPs. The area extends from 28.0° N to 40.6° N latitude and 58.0 ° E to 50.3° E longitude, LROC WAC 643nm mosaic. IMP labels: Aristarchus (A), Gruithuisen E-M region (GEM), Hyginus (H), Ina (I), Mare Nubium (MN),  Mare Tranquillitatis (MT), Marius Hills (MH), Maskelyne (M), Sosigenes (S) [NASA/GSFC/Arizona State University].
Pursuing a Decades-old Puzzle

The best-known IMP, called Ina (or Ina-D), was originally spotted in Apollo 15 orbital photography, and was unlike anything else previously discovered on the lunar surface. Beginning with Apollo era investigations, Ina was interpreted as a collapsed caldera at the summit of a low-shield volcano. Previous interpretations of impact crater densities within and around Ina suggested that this enigmatic landform was much younger than the surrounding mare basalt unit in Lacus Felicitatis (Lake of Happiness).

Not only does the NAC provide excellent resolution, but after 5 years of operation has covered well over 75% of the surface. This combination led to the discovery of many new IMPs in locations across the nearside of the Moon. Ina is not simply a one-off oddity – but rather a signature of volcanic processes that actually occurred in multiple places across the nearside.

Close up of a small 464 meter wide section of the "IMP" familiarly known as Ina. This area is a great example of the difference between the rough and smooth units that make up the new family of IMP structures. The smooth unit is composed of mounds over the rougher units. The Sun is from the East, the black arrows show a Sun-facing cliff of one of the mounds. LROC NAC M175246029LR, LRO orbit 10960, November 6, 2011; 45.6° incidence, resolution 44 cm from 24.54 km over 18.91°N, 4.76°E [NASA/GSFC/Arizona State University].
New Discoveries

All of the lunar landforms identified as IMPs exhibit two distinct morphologies: smooth deposits, which are sometimes connected to the surrounding mare basalt, and uneven deposits (rough-looking) which usually end abruptly at the steep edges of the smooth deposit; it is likely that the smooth materials are covering portions of the rough material.

To estimate the age of IMPs the LROC team measured the sizes and numbers of impact craters on the smooth deposit surfaces (geologists use the crater size-frequency distribution (CSFD) as a metric for estimating the age of a surface). The resulting crater distributions from the three largest irregular mare patches imply ages younger than 100 million years. Indeed, the new crater counts confirmed that Ina is very young, perhaps as young as 33 million years.

IMP north of Aristarchus crater (25.044°N, 313.233°E). Compelling evidence of the youth of this feature and its apparent origination from active processes within the Moon. As a matter of stratigraphy, the phenomena that caused this occurred after the formation of Aristarchus crater, a late Copernican age crater itself superposed on some of the Moon's youngest basaltic volcanic plains. 650 meter-wide field of view from LROC NAC observation M168509312R, LRO orbit 9967, August 20, 2011; incidence 42.67° at 40 cm resolution from 25.59 km over 24.7°N, 313.21°E [NASA/GSFC/Arizona State University].
Another key set of observations came from digital topographic maps derived from NAC stereo pairs that enabled quantitative relief and slope measurements of six larger IMPs. Measurements of the smooth deposit relief compared to the underlying uneven deposit revealed that the thickness of the smooth deposits (on average 8 meters, with a range of 2-20 meters) is consistent with the previously established thickness of lunar basalt flows.

Topographic slopes were measured at the edges of the smooth deposits where they contact the uneven deposits. Slopes that exceed the angle of repose, which is 30-35°, are evidence of relatively young surface features, because over time impacts and moonquakes will smooth over steep cliffs. Slopes on the edges of many of the smooth deposits exceed the angle of repose, providing more evidence for very young surfaces.

Changing the Way We Think About the Moon

Not only are the IMPs striking landscapes, they also tell us something very important about the thermal evolution of the Moon. The nearside has extensive mare basalt flows covering much of its surface, however we know from analysis of Apollo samples and crater counts that the bulk of lunar volcanism occurred from 3.9 to 3.1 billion years ago, and shut-off sometime around 1 billion years ago. However the IMPs seemed to have formed significantly after the canonical cessation of lunar mare basalt volcanism indicating the interior of the Moon is perhaps hotter than previously thought.

The contrast between the smooth and rough units stands out in this oblique view of Ina. The floor of the depression is about 50 m below the surrounding plains and is about 2 km wide. LRO oblique mosaic M1108203502LR, LRO orbit 15596, November 22, 2012; 52.18° slew from orbital nadir, resolution 3.75 meters from 127.29 km over 18.77°N, 11.64°E [NASA/GSFC/Arizona State University].
Full-width reduction of LRO oblique mosaic M1108203502LR, showing the interesting contextual features, some related, others likely not, subject of decades of speculation [NASA/GSFC/Arizona State University].
The new study of IMPs extends our knowledge of the extent of these fascinating deposits as well as their young age. What does it all mean? The young, small-volume extrusions of mare basalt imply a thermal history of the Moon where volcanism did not end abruptly, but rather decreased gradually over time (and may not be done!). With these newly discovered young volcanic features, scientists must consider that the Moon has a bit more heat in it that previously thought, an important new constraint for future models of the Moon's thermal evolution. Perhaps the abundance of radioactive elements (which provide heat as they decay) is higher -- important knowledge when figuring out how the Moon formed and evolved over time.

A provocative side note to the new thermal constraints — perhaps the Apollo heat flow measurements were spot on? Astronauts buried thermometers in the regolith during the Apollo 15 and 17 missions. The temperatures recorded were a bit higher than models predicted. At the time, scientists proposed that perhaps the two landing sites were in areas with higher heat flow than the average Moon, or perhaps there was an instrumental effect. The discovery of IMPs and their young age is certainly consistent with the higher temperatures measured by the Apollo crews.

Apollo 15 cmdr. Dave Scott working at the west Heat Flow hole (with St. George crater in the background). The drill is sitting on the ground next to the hole. Increased understanding of IMP phenomena increases the likelihood readings taken using the Apollo Heat Flow Experiments (HFE) during the Apollo 15 and 17 surface expeditions were not, afterall, anomalous. Apollo 15 EVA-2 AS15-92-12408 [NASA/JSC].
The IMPs are a fascinating part of the story of lunar volcanism over time, and now they must be considered high priority targets for future exploration. A sample return mission from one of these enigmatic deposits would tell us so much about the Moon as a whole. When did these lavas erupt? Is their chemistry different than the basalts returned by the Apollo astronauts? Is it likely that volcanic eruptions may occur at some point in the future?  A highly accurate age date for the IMPs would also serve as a much needed calibration point for the lunar cratering chronology; a crucial improvement not only for lunar studies but also for Mars and Mercury investigations.

Closer look at the IMP at Rimae Sosigenes - image follows below - Demonstrations Supplementary to "Evidence for basaltic volcanism on the Moon within the past 100 million years," Nature Geoscience 7, 787-791; 2014

Fig. 7 (top) Profile across a contact between smooth and uneven deposits, southeast feature. The relief of the smooth deposit is measured as the difference in elevation between the average flat surface of the smooth deposit (-1504 meters below global mean elevation; Sosigenes Graben NAC-DTM) and the base of the uneven deposit at the contact (-1514 meters). For this particular profile the smooth deposit is 10 meters thick. Note the lobate margin of the smooth deposit at the contact.

Fig. 5 (bottom) Craters on the smooth deposit of the Sosigenes IMP. The red circles are impact craters superposed on the smooth deposit of the Sosigenes IMP, delineated by the blue line; field of view roughly 5 km [NASA/GSFC/Arizona State University].
Spectacular oblique mosaic of the Sosigenes graben with it's large collapse pit, 2800 meters long and 300 meters deep, and floored with an IMP.  LROC NAC oblique observation M1108117962LR, LRO orbit 15584, November 21, 2012; 70.37° incidence, spacecraft and camera slew 55° resolution 2.5 meters from 114.87 km over 8.63°N, 24.9°E [NASA/GSFC/Arizona State University].
View full-window: Spectacular oblique NAC mosaic of the Sosignes graben with a large collapse pit (2800 meters wide, left-to-right; 300 meters deep) floored with an IMP.

Wider field of view from a spectacular oblique LROC NAC mosaic M152750200LR, LRO orbit 15584, November 21, 2012; 70.37° incidence, spacecraft and camera slew 55° resolution 2.5 meters from 114.87 km over 8.63°N, 24.9°E [NASA/GSFC/Arizona State University].
Inspect a variety IMPs using the LROC Quickmap: Cauchy-5, Nubium, GEM-30, Aristarchus North

Related Posts:
Inside Rima Hyginus (June 12, 2012)
Ina of the Meniscus Hollows (March 21, 2012)
Spectral properties of Ina (February 7, 2011)