Thursday, January 31, 2013

ESA: Building a Lunar Base with 3D Printing

For ESA's 3D-printed lunar base concept, Foster+Partners devised a weight-bearing ‘catenary’ dome design with a cellular structured wall to shield against micrometeoroids and space radiation, incorporating a pressurised inflatable to shelter astronauts [ESA/Foster+Partners].
Setting up a lunar base could be made much simpler by using a 3D printer to build it from local materials. Industrial partners including renowned architects Foster + Partners have joined with ESA to test the feasibility of 3D printing using lunar soil.

“Terrestrial 3D printing technology has produced entire structures,” said Laurent Pambaguian, heading the project for ESA.

“Our industrial team investigated if it could similarly be employed to build a lunar habitat.”

Foster + Partners devised a weight-bearing ‘catenary’ dome design with a cellular structured wall to shield against micrometeoroids and space radiation, incorporating a pressurised inflatable to shelter astronauts.

The UK’s Monolite supplied the D-Shape printer for ESA's 3D-printed lunar base study, with a mobile printing array of nozzles on a 6 meter frame to spray a binding solution onto a sand-like building material. 3D ‘printouts’ are built up layer by layer – the company more typically uses its printer to create sculptures and is working on artificial coral reefs to help preserve beaches from energetic sea waves. First the simulated lunar material with magnesium oxide – turning it into ‘paper’ to print with. Then for structural ‘ink’ a binding salt is applied which converts material to a stone-like solid [ESA/Monolite].
A hollow closed-cell structure – reminiscent of bird bones – provides a good combination of strength and weight.

The base’s design was guided in turn by the properties of 3D-printed lunar soil, with a 1.5 tonne building block produced as a demonstration.

“3D printing offers a potential means of facilitating lunar settlement with reduced logistics from Earth,” added Scott Hovland of ESA’s human spaceflight team.

Sculpture produced by Monolite using 3D printing [ESA/Monolite].
“The new possibilities this work opens up can then be considered by international space agencies as part of the current development of a common exploration strategy.”

“As a practice, we are used to designing for extreme climates on Earth and exploiting the environmental benefits of using local, sustainable materials,” remarked Xavier De Kestelier of Foster + Partners Specialist Modelling Group. “Our lunar habitation follows a similar logic.”

The UK’s Monolite supplied the D-Shape printer, with a mobile printing array of nozzles on a 6 m frame to spray a binding solution onto a sand-like building material.

This 1.5 metric tonne building block was produced as a demonstration of 3D printing techniques using lunar soil. The design is based on a hollow closed-cell structure – reminiscent of bird bones – to give a good combination of strength and weight [ESA].
3D ‘printouts’ are built up layer by layer – the company more typically uses its printer to create sculptures and is working on artificial coral reefs to help preserve beaches from energetic sea waves.

“First, we needed to mix the simulated lunar material with magnesium oxide. This turns it into ‘paper’ we can print with,” explained Monolite founder Enrico Dini.

“Then for our structural ‘ink’ we apply a binding salt which converts material to a stone-like solid.

“Our current printer builds at a rate of around 2 m per hour, while our next-generation design should attain 3.5 m per hour, completing an entire building in a week.”

Italian space research firm Alta SpA worked with Pisa-based engineering university Scuola Superiore Sant’Anna on adapting 3D printing techniques to a Moon mission and ensuring process quality control. The effect of working in a vacuum was also assessed.

“The process is based on applying liquids but, of course, unprotected liquids boil away in vacuum,” said Giovanni Cesaretti of Alta.

“So we inserted the 3D printer nozzle beneath the regolith layer. We found small 2 mm-scale droplets stay trapped by capillary forces in the soil, meaning the printing process can indeed work in vacuum.”

Simulated lunar regolith is produced for scientific testing by specialist companies, typically sold by the kilogram. But the team required many tonnes for their work.

“As another useful outcome, we discovered a European source of simulated lunar regolith,” added Enrico.

“Basaltic rock from one volcano in central Italy turns out to bear a 99.8% resemblance to lunar soil.”

“This project took place through ESA’s General Studies Programme, used to look into new topics,” Laurent commented.

“We have confirmed the basic concept, and assembled a capable team for follow-on work.”

Factors such as controlling lunar dust – hazardous to breathe in – and thermal factors will require further study.

3D printing works best at room temperature but over much of the Moon temperatures vary enormously across days and nights lasting two weeks each. For potential settlement, the lunar poles offer the most moderate temperature range.

Setting up a future lunar base could be made much simpler by using a 3D printer to build it from local materials. Industrial partners including renowned architects Foster+Partners have joined with ESA to test the feasibility of 3D printing using lunar soil.

The base is first unfolded from a tubular module that can be easily transported by space rocket. An inflatable dome then extends from one end of this cylinder to provide a support structure for construction. Layers of regolith are then built up over the dome by a robot-operated 3D printer (right) to create a protective shell [ESA/Foster+Partners].

Messy melt in the Lodygin crater group

Unlike some melt ponds, this melt pond does not look very smooth! LROC Narrow Angle Camera (NAC) observation M182116507LR, spacecraft orbit 11945, January 25, 2012; field of view 910 meters at 0.96 meters resolution (incidence angle 57.43°) from 94.9 km [NASA/GSFC/Arizona State University].
Lillian Ostrach
LROC News System

Impact melt forms during crater formation when part of the impact-generated shock wave energy released during the impact event is released as heat. As the shock wave passes through the target, the amount of melting is related to the shock pressures reached during impact (for more information, see Chapter 6 in Traces of Catastrophe, by Bevan French). 

Often, impact melt appears visually smooth in LROC images, particularly at the WAC scale and in large craters like Tycho. However, Narrow Angle Camera (NAC) observations like today's Featured Image show that impact melt does not always have a flat "ponded" surface. In this case, the melt ponds inside an ~5 km diameter crater (17.121°S, 215.646°E) are far from smooth. 

Why might this be the case?

Full 9.9 km-wide mosaic of both left and right frames of LROC NAC observation M182116507 [NASA/GSFC/Arizona State University].
LROC WAC monochrome mosaic of the unnamed crater in the midst of the Lodygin crater group, in the farside highlands terrain north of the Apollo basin. (Asterisk notes location of the field of view shown at high-resolution in the LROC Featured Image released January 31, 2013 [NASA/GSFC/Arizona State University].
Sometimes impact melt appears visually smooth because there is enough melt that pools to cover up the fragmented floor of the crater or wall terrace. When there is less melt, the melt may pool in localized depressions to create smoothed surfaces as well as cover the surrounding fragmented, jumbled rocks pulverized during impact. Another possibility is that as the melt formed and began to cool on the crater floor, fragmented material fell from the crater walls and rim into the crater cavity to become mixed and entrained within the melt, helping to form a rugged melt-covered crater floor.

Examine the full LROC NAC image, HERE, to see if you can discern material that was entrained before the melt cooled and blocks that may have fallen to the crater floor at a later date!

Related Posts:
Anaxagoras Exterior Melt
Rim on a Rim
Louville D

Watch a Magical Moonrise

Nancy Atkinson
Universe Today

This is absolutely lovely. Photographer Mark Gee says this incredible real-time video “is as it came off the memory card and there has been no manipulation whatsoever.” It shows the full Moon rising over the Mount Victoria Lookout in Wellington, New Zealand. 

Read more HERE.

Wednesday, January 30, 2013

Boulder Fields

Boulders of various sizes (a few meters up to around 20 meters) scattered across the lunar surface. Where do these boulders originate? LROC Narrow Angle Camera (NAC) observation M170605553LR, LRO orbit 10276, September 14, 2011; resolution 51 cm per pixel over a field of view 510 meters across, viewed from 47 km [NASA/GSFC/Arizona State University].
Lillian Ostrach
LROC News System

Featured Images occasionally highlight lunar boulders larger than a few meters. Observed on crater floors, near crater rims, and clustered atop wrinkle ridge crests, boulders provide excellent sampling opportunities for exploration (think: Station 6 Boulder samples from Apollo 17 helped scientists understand local and regional geology). However, like any terrestrial field location, context is crucial to developing a plan for fieldwork and sampling, and even though planetary scientists frequently rely on remotely sensed data, these scientists cannot test hypotheses unless they know where and what they are observing! So, looking at the image above, where is this boulder field located (crater floor? crater rim? wrinkle ridge? elsewhere?) and from where did these boulders originate?

Reduced resolution view of the crater in the opening image. White box is approximate location of opening image field of view, LROC NAC M170605553LR, image width 2.5 km [NASA/GSFC/Arizona State University].
Taking a look at the zoomed out view in a reduced resolution NAC image, it becomes apparent that the opening image is located immediately exterior to the southern crater rim of an unnamed, 1.8 km diameter crater (located at 58.408°N, 351.859°E in Mare Frigoris). With this context, the location of the boulder field is revealed to be outside a mare crater. Furthermore, the origin of the boulder field is ejected material from the impact crater formation. Going back to the exploration thought - why would these boulders be advantageous to sample?

LROC WAC monochrome mosaic centered on the unnamed crater in Mare Frigoris, north-northeast of the Plato crater group; arrow notes the location shown at high resolution in the LROC Featured Image released January 30, 2013. Buried deep under this region is the antipodes, the opposing side of the Moon, of the primeval impact that formed South Pole-Aitken basin [NASA/GSFC/Arizona State University].
Sampling boulders close to the crater rim provides explorers the opportunity to collect rocks in a "radial traverse". The material right on the rim is mostly from deep within the crater and material further from the rim is from shallower within the crater. So as you approach a crater rim, the ejecta is progressively from deeper within the crater. This technique was employed by the Apollo 14 astronauts at Cone crater.

In the case of today's crater, the rocks sitting on the rim are from about 150 m below the surface even though the crater depth is about 360 m. During impact, part of the crater formation results from compression of the target and excavation flow (sideways movement of material), and for simple craters (less than 15 km diameter) an estimate of excavation depth is Hexc=0.1Dt, where Hexc is depth of excavation and Dt is transient crater diameter (diameter of the crater cavity at the conclusion of the excavation stage, before post-impact modification begins). The transient crater diameter can be estimated from the observed rim-to-rim diameter (what we measure today) using the relationship Dt=0.84D, where D is observed crater diameter. These relationships are explained in detail in Impact Cratering: A Geologic Process, by H. J. Melosh (1989).

Explore this 1.8 km impact crater in a virtual traverse using the full LROC NAC image, HERE.

Related Posts:
Sampling Schrödinger
Boulder trails in Menelaus crater
Physics is Fun!

Tuesday, January 29, 2013

New web-based ArcGIS tool for evaluating proposed landing sites within South Pole-Aitken basin

A very young adornment upon a very old place. Can all the Science Goals outlined in the influential 2007 NRC study "Scientific Context for the Exploration of the Moon" be addressed at South Pole-Aitken basin? An exceptional dark, fresh debris slide down the wall and floor of Fechner T (58.74°S, 122.82°E) a youthful 14 km crater thought to have excavated primeval material originally dredged up by the 4.1 billion year old South Pole-Aitken basin. LROC NAC observation M169772751R, LRO orbit 10153, September 4, 2011; incidence angle 60.16° at roughly 58 cm per pixel resolution, from 55 km [NASA/GSFC/Arizona State University].
David Kring
Lunar and Planetary Science Institute

The LPI-JSC Center for Lunar Science and Exploration, in support of the NLSI South Pole-Aitken Basin Focus Group, has developed a new web-based ArcGIS tool for evaluating landing sites within the South Pole-Aitken (SPA) basin.  This focus on the SPA basin is prompted by several reports.  

A yellow ellipse marks the location of a valuable future landing site proposed by students participating in LPI Summer Intern program, within "walk-back distance" from a Copernican age crater perched high on a Schrödinger basin peak ring. LROC Wide Angle Camera (WAC) M169698283CE (604nm), LRO orbit 10142, September 3, 2011, resolution 81 meters from 58.55 km [NASA/GSFC/Arizona State University].
The National Research Council’s 2007 report, The Scientific Context for Exploration of the Moon, concluded the second highest priority is to determine the age of the SPA basin via sample return.  In the National Research Council’s 2012 report Vision and Voyages for Planetary Science in the Decade 2013-2022, a sample return mission was also a high-priority option for a New Frontier-class mission.  Several formal and informal recommendations by others in the community have also pointed to the SPA basin as a high-priority science and exploration target.

This novel web-based ArcGIS system provides co-registered base maps (e.g., topography and FeO abundances) and a series of feature layers (e.g., for volcanic rilles and ≥20 km-diameter impact craters).  Using the ArcGIS tool, users can zoom into lunar surface sites of potential interest.

Important:  This novel tool is accessible from browsers.  You do not need ArcGIS or a license to use ArcGIS on your computer – the system uses a new type of platform that will make it easier for people in the community to access SPA-related data.

The system is also integrated with information used in a previous lunar landing site assessment of the South Pole-Aitken Basin that was developed through the NLSI and the LPI-JSC Lunar Exploration Summer Intern Program.   That study determined that most of the goals articulated by the NRC (2007) report could be addressed within the SPA basin and highlighted, in particular, the attractiveness of Schrödinger basin and Amundsen crater for future missions. As users will see, however, there are a huge number of other interesting locations within SPA.

The oldest and largest verified impact basin, 2100 km-wide South Pole-Aitken, now believed by many to be oblong though the location of its central transitory morphological center remains elusive. Lunar Reconnaissance Orbiter laser altimetry (LOLA) [NASA/GSFC].
Data have been imported at the highest resolution available, although the data bandwidth for a real-time, on-line system currently limit the display of that data to 1000 meters.  This system is designed to evolve, however, so that it can provide the lunar community with an enhanced range of information and capabilities in the future. Additional base maps and feature layers are already in development for a second version that will be installed as soon as possible.

The url for the new South Pole-Aitken Basin Landing Site Database is

Clam Shell on the wall of Lalande C

An oblique impact crater on the wall of Lalande C crater. LROC Narrow Angle Camera (NAC) M170606751LR, LRO orbit 10276, September 14, 2011; incidence angle 11.82° at 49 cm per pixel resolution revealing a field of view 600 meters across, viewed from 44.83 km [NASA/GSFC/Arizona State University].
Lillian Ostrach
LROC News System

Oblique impact craters can form when the angle of impact is less than 15° from the horizontal or from impact into sloped terrain.

Oblique impact craters typically exhibit specific morphologies: asymmetric ejecta and non-circular (more elliptical) crater shapes. The approximately 220 meter impact crater in today's Featured Image (5.668°S, 353.148°E) formed on the interior crater wall of Lalande C and is a nice example of a small, oblique impact crater that formed due to target slope as opposed to impact angle.

The oblique crater in Lalande C does have an asymmetric ejecta blanket (see the full NAC image) and a poorly defined zone of avoidance. The crater shape is not circular; instead, the irregular crater shape is reminiscent of a clam shell. There is also a blocky jumble of mostly high-reflectance material collected downslope of the crater, where the rim would be. What could explain the presence of this material?

LROC WAC monochrome mosaic centered on Lalande C crater (10.5 km diameter, 5.596°S, 353.041°E), where the asterisk marks the location of the field of view shown at high resolution in the LROC Featured Image released January 29, 2013 [NASA/GSFC/Arizona State University].
Circular, or bowl-shaped, craters form when impact occurs greater than 15° from the horizontal (the most probable angle of impact is 45°), and material from within the crater is ejected ballistically to form an expansive, symmetric ejecta blanket. However, because the bolide impacted into the sloped crater wall, the material ejected from the crater in today's Featured Image did not form a symmetric ejecta blanket. What this means is that the jumble of high-reflectance material is probably excavated material that was ejected at low velocity from the crater during crater formation. LROC NAC images of oblique craters such as this one show similar features and certainly require additional study!

Take a look for yourself in the full LROC NAC image! Can you identify the extent of asymmetric ejecta superposed on the wall of Lalande C?

Related Posts:
Rim on a Rim
Rim Impact
Slice of Mare

Monday, January 28, 2013

A Russian Moon?

Another design for renewing Russia's groundbreaking program of robotic lunar exploration is set aside. Above is a 2008 notional concept of the Roscosmos Luna-Glob orbiter, equipped with penetrators and supporting both a lander and an ISRO-built rover, part of a highly anticipated international mission recently abandoned. Under the Soviet regime Russia pioneered and brought to an end exploration of the Moon's surface [IKI/Lavochkin].
Dwayne Day
The Space Review

Earlier this month the Russian government announced that it plans to launch a lunar orbiter in 2015, followed by a lander a year later, both of them designated Luna-Glob. This is the latest version of what has been a rather convoluted series of Russian announcements about their planetary exploration plans, particularly with regards to the Moon. Previous plans had involved launching the orbiter and lander together, then changed to launch the lander a year before the orbiter. Now the Russians have switched the order. This is a more logical plan than previous ones, and at least to outsiders it appears as if the Russians are starting to develop a more sensible sequence of planetary science missions, as well as mission goals, than they have in the past. It’s something we should hope for, as the Russians could possibly by the most active nation conducting lunar exploration in the next decade.

Although they have experience with landing robotic craft on the Moon, launching a Moon orbiter before a lander is a better approach for the Russians because they need to re-learn how to walk before they can start to run. In late 2011 they suffered an embarrassing failure of their overly-ambitious Fobos-Grunt mission. The spacecraft fell silent almost immediately after launch, circled the Earth for a few weeks, and finally reentered. Many independent observers had predicted that Fobos-Grunt would fail because it was too complicated for a space program that had not built a planetary spacecraft in over a decade and a half (see “Red moon around a red planet,” The Space Review, November 7, 2011). The only real surprise was that the spacecraft failed so early, probably a sign that Russian quality control and systems engineering are both in bad shape, something that has been reinforced by a series of launch vehicle problems. Russian planetary science plans in recent years appeared to experience the “Christmas Tree” problem that American robotic spacecraft suffered from in the 1980s. This is where a mission gets more and more complex as scientists add more instruments, increasing the cost and the risk that something will go wrong. Fobos-Grunt had this problem in spades and some Russian lunar missions appeared to be succumbing to it as well. A single mission including an orbiter, lander, and rover, some of them from different countries, is very hard to integrate, but until recently such a mission was in Russian lunar plans.

Read the full article at The Space Review, HERE.

Location selection and layout for LB10, a lunar base at the Lunar North Pole with a liquid mirror observatory

LROC Wide Angle Camera (WAC) Shaded DTM of the Moon's highest northern latitudes, with the preferred location of a proposed telescope base marked, supported by ten personnel (LB10) [NASA/GSFC/DLR/Arizona State University].
Emmanouil Detsis, Ondrej Doule, Aliakbar Ebrahimi
International Space University (ISU)
Acta Astronautica, 2013

We present the site selection process and urban planning of a Lunar Base for a crew of 10 (LB10), with an infrared astronomical telescope, based on the concept of the Lunar LIquid Mirror Telescope. LB10 is a base designated for permanent human presence on the Moon. 

The base architecture is based on utilization of inflatable, rigid and regolith structures for different purposes. The location for the settlement is identified through a detailed analysis of surface conditions and terrain parameters around the Lunar North and South Poles. 

A number of selection criteria were defined regarding construction, astronomical observations, landing and illumination conditions. The location suggested for the settlement is in the vicinity of the North Pole, utilizing the geographical morphology of the area. The base habitat is on a highly illuminated and relatively flat plateau. The observatory in the vicinity of the base, approximately 3.5 kilometers from the Lunar North Pole, inside a crater to shield it from Sunlight. An illustration of the final form of the habitat is also depicted, inspired by the baroque architectural form.

Preview the article and illustrations, HERE.

Fig. 7. Telescope location I with additional sintered structures. The coordinates of the crater are 89.9°N, 147.34°E.

WSJ Op-Ed calls for scrapping SLS

In an essay in Monday’s issue of the Wall Street Journal, Robert Walker and Charles Miller make a pitch to President Obama: complete the job he started in his first term in handing over space transportation entirely in the private sector. “Just as the government does not design or build automobiles, ships, trains or airplanes, NASA should not be designing, building or launching rockets to go to low Earth orbit,” they argue. 

Specifically, they want the President to kill the Space Launch System, the heavy-lift rocket that emerged from the 2010 compromise about the administration’s policy, saying that those launches should be turned over to the private sector. 

Read the summary, HERE.

Friday, January 25, 2013

Geological mapping of another world

Eugene Shoemaker with some of the first geological maps of the Moon, in Flagstaff, Arizona during the mid-1960's
Paul D. Spudis
The Once & Future Moon
Smithsonian Air & Space

Many people are surprised when they learn that well before the first landing of Apollo in 1969, we already understood the geological history of the Moon.  The idea that such a thing was even possible drew considerable skepticism during early preparations for landing on the Moon.  The principles for the remote mapping of the geology of the Moon came from several closely related but distinct threads.  Eugene M. Shoemaker, a geologist with the U. S. Geological Survey (USGS) who founded the Branch of Astrogeology, laid out the methodology in broad outline from and through the systematic study of lunar surface images in the early 1960s.

One of the basic principles of geology is that younger rocks lie on top of (or intrude into) older rocks.  Interestingly, this relationship can be discerned from a photograph.  In the case of the Moon, images show the dark smooth plains of the maria (lava) and the rough, cratered highlands.  Some craters were found on top of the dark mare plains, while others were filled with mare.  Clearly, the craters on top of the mare formed after those plains existed and were thus younger than the maria.  On the other hand, dark mare that fills a crater must have formed after that crater existed and so in this case, the crater was older.

By following these simple relations over large areas, it is possible to determine the relative ages of mare and craters, both among themselves and to each other.  But such information is trivial unless we can relate these individual ages to some unit or event of regional significance.  In principle, if such a relationship can be defined we can extend relative age assignments over large areas, ultimately on a global basis.

The first effort to map the geology of the Moon was by the USGS, but not by the then-newly created Astrogeology Branch.  Branch of Military Geology scientists Arnold Mason and Robert Hackman produced the “Engineer’s Special Study of the Moon” in 1960.  This special one-off product documented the principal terrain types of the Moon (maria and highlands) and ordered features into three categories of relative age: post-mare craters (youngest), maria, and highlands (oldest).  Additionally, the map showed the distribution of linear features, presumed to be faults (fractures along which movement has occurred), and mare ridges (presumed to be folds) over the near side.  In this sense, the Engineer Special Study was a geological map because it showed the spatial distribution of rock types, their relative ages, and the inferred structure of the lunar surface.  This map was accompanied by a detailed text chart, which showed a region-by-region evaluation of the terrain and construction challenges for each area.  But a critical element was still missing.

On Earth, the geologist recognizes the rocks in the field, maps their locations and orientation, and documents the structure of the area under study.  But a key part of this work is to figure out where a particular area fits in the global column of geologic units.  On Earth, by documenting the slow, gradual nature of geological processes the stratigraphic column was developed slowly over the course of about a hundred years.  The terrestrial stratigraphic column also provided key evidence needed to show the gradual transition of life forms from simple invertebrate organisms in the earliest rocks, to the complex and varied life forms in succeeding strata.  With the development of a global stratigraphic system and accompanying geologic time scale for the Earth, a framework for understanding the history and processes of the Earth was created.

Gene Shoemaker recognized the need for an organized stratigraphy to aid in our understanding of the Moon.  He wanted to understand the Moon’s evolution and age, but also to correlate events on the Moon with events in Earth history.  He recognized that a major step forward to such an end was to define a formal stratigraphic system for the Moon – a clear succession of rock types with key regional units defining the system boundaries.  He began mapping the area around the crater Copernicus, which lies on the central near side of the Moon, recognizing that the rocks exposed there (from what had been discerned from images) represented all the distinct phases of lunar history.

From Earth, a telescopic image of Copernicus and vicinity, showing how the relative ages of geological features are determined using the principle of superposition.
The basic sequence is easy to follow.  The oldest rocks (1) are those that form the highland units of the large, circular Imbrium impact basin.  These units are the mountains that make up the rim of the basin as well as the regional highlands around Copernicus, which are ejecta from the basin forming event.  Partial flooding by the dark, smooth maria followed (2), including both dark, ash-like materials and smooth flood-like plains (interpreted even then as flows of basalt, the most common volcanic rock type on Earth).  These eruptions were followed by the formation of impact craters, of which two kinds could be recognized:  an older group (3) that had slightly eroded and lost their bright rays (such as Eratosthenes) and a younger group (4) that preserved the bright rays and showed a fresh, unmodified form (such as Copernicus.)

Shoemaker used these rock units to define the lunar time-stratigraphic systems:  the Imbrian, Procellarian, Eratosthenian and Copernican Systems were each assigned to represent an archetypical deposition event.  Rocks that existed before the formation of the Imbrium basin were assigned to an informal category, the pre-Imbrian.  Thus, Shoemaker created a geologic map that not only showed the distribution of rock units and the structure of a given area, but also classified these rock types into a stratigraphic column for the Moon, one that (because of the enormous extent of the Imbrium basin) could be applied to areas across the lunar near side.  With slight modification (the “Procellarian” System is no longer used and the pre-Imbrian has been subdivided into the Nectarian System and pre-Nectarian), this classification scheme subsequently has been applied to the entire Moon.

Shoemaker’s work on geologic mapping of the Moon gave us the ability to immediately put the lunar samples returned by Apollo into a regional and global context.  We found that most lunar events occurred very early in its history, with intense geological activity in the first 1-2 billion years and little activity since.  Thus, the Moon’s geological record perfectly complemented that of the Earth, whose traces of earliest activity have been erased over time by the active processes of erosion and plate tectonics.

The first geologic quadrangle map of the Moon, showing rock units (basin, crater and mare materials), structures and their stratigraphic arrangement.
The 1960 Copernicus Prototype Chart LPC-58, the first true geological map of the Moon, was not formally published by the USGS, though a modified and updated version was published later in that decade.  By then, Gene had picked up a couple of co-authors for his effort, including one Harrison Hagan Schmitt (a young geologist with the USGS in the early 1960s), who in 1972 ultimately got the chance on the Apollo 17 mission to do what Gene Shoemaker originally got into the space business to do – check the interpretations of the remote lunar geologic mapping by doing field work on the Moon.

Click HERE to view Shoemaker’s LPC-58 geological map at full resolution.

Just publishedThe Clementine Atlas of the Moon, Revised Edition, an updated atlas and reference guide to lunar features, by Ben Bussey and yours truly.

Originally published at his Smithsonian Air & Space Magazine blog "The Once and Future Moon," Dr. Spudis is a senior staff scientist at the Lunar and Planetary Institute. The opinions expressed are those of the author and are better informed than average.

Thursday, January 24, 2013

'When we blew up Arizona to simulate the Moon'

The first round alone required 141.75 kg of dynamite and 6120 kg of fertilizer mixed with fuel oil. Archive photograph [NASA/USGS].
Geoff Manaugh and Nicola Twilley
The Atlantic

In the late 1960s, NASA created an off-world analogue with dynamite and fertilizer bombs outside Flagstaff, Arizona, so that astronauts could train for the Apollo missions.

Thanks to a well-timed tip from landscape blogger Alex Trevi of Pruned, Venue made a detour on our exit out of Flagstaff, Arizona, to visit the old black cinder fields of an extinct volcano--where, incredibly, NASA and its Apollo astronauts once practiced their, at the time, forthcoming landing on the moon.

The straight-forwardly named Cinder Lake, just a short car ride north by northeast from downtown Flagstaff, is what NASA describes as a lunar analogue: a simulated off-world landscape used to test key pieces of gear and equipment, including hand tools, scientific instruments, and wheeled rovers.

Apollo 15 Jim Irwin and Dave Scott of Apollo 15 train in experimental vehicle "Grover" [NASA/USGS].
As Northern Arizona University explains, NASA's Astrogeology Research Program "started in 1963 when USGS and NASA scientists transformed the northern Arizona landscape into a re-creation of the Moon. They blasted hundreds of different-sized craters in the earth to form the Cinder Lake crater field, creating an ideal training ground for astronauts."

Read the full and copiously illustrated article HERE.

Carle Pieters and David Kring present NLSI seminar Tuesday, January 29 - also available online

NASA Lunar Science Institute Seminar
NASA Ames Research Center
Moffett Field, California
1800 UT (1:00 pm EST) 29 January 2013
Available Online

The Moon: Brimstone to Keystone, Touchstone, and Cornerstone
Carle M. Pieters of Brown University.

The Earth and the Moon share a common early origin, but subsequent geologic evolution has led to quite different planetary bodies that reside in the same part of the solar system. A remarkable array of new lunar data acquired by an international armada of spacecraft over the last decade has stimulated a renaissance of inquiries about the character of the Moon and how its properties can be used to truly understand fundamental processes active on and in a planetary body. "The Moon as Cornerstone to the Terrestrial Planets" team of the NASA Lunar Science Institute is jointly hosted by Brown University and MIT faculty who share a long history of science interactions. The NLSI structure has enabled widespread science interactions and spawned active involvement by the next generation of researchers and scientific leaders. Activities range from probing the deep internal dynamo of the ancient Moon to characterizing space weathering processes active on the present surface - all leading to new strategies for human and robotic exploration.

Discoveries along a path to a new age of science and exploration
David A. Kring of the Lunar and Planetary Institute.

Our NLSI team was designed to develop a core, multi-institutional lunar science program that addresses the highest science priorities; provide scientific and technical expertise to NASA that will infuse its lunar research programs, including developing investigations that influence current and future space missions; support the development of a lunar science community that both captures the surviving Apollo experience and trains the next generation of lunar science researchers; and use that core lunar science to develop education and public outreach programs that will energize and capture the imagination of K-14 audiences and the general public. We have succeeded beyond our proposed expectations. We dramatically sharpened our understanding of impact bombardment, from the accretional growth of planets to the terminal cataclysm that reshaped the entire solar system c. 3.9 Ga. The team helped NASA develop mission scenarios (e.g., to Malapert Massif and to the Earth-Moon L2 position), conduct a global survey of lunar landing sites, and identify the most attractive sites for both robotic and human exploration (e.g., Schroedinger basin, SPA basin, and Amundsen crater). We have also helped field tests of mission scenarios, to both the Moon and NEA, with astronauts and the LER-SEV in the DRATS analog program.

Dr. Carle Pieters is a professor of Geological Sciences at Brown University and is PI of the Brown/MIT NLSI team, involving 22 Co-Investigators, 9 Collaborators, and a large and continually evolving group of students and post-docs. The Brown/MIT NLSI team links the talents of investigators at 9 US and 6 foreign institutions. Dr. Pieters obtained a master's then PhD degree at MIT in 1977 and has been pursuing the mysteries of the Moon ever since as research evolved with significant improvement in laboratory and remote sensing capabilities. Her research focuses on compositional evolution of the crust and properties of the regolith and uses an increasingly sophisticated array of spectroscopic tools, including the Moon Mineralogy Mapper, which she recently led as PI. She is committed to collaborative research and Co-chaired the 2007 NRC report "Scientific Context for Exploration of the Moon". She is a Fellow of AGU, AAAS, and GSA and has been awarded the Kuiper Prize (AAS/DPS) and G. K. Gilbert Award (GSA).

Dr. David A. Kring represents a 40-member science and exploration team, including international partners in 4 countries, and a 20-member higher education consortium, that collectively have trained 14 postdoctoral researchers and approximately 100 graduate students. PI Kring received his Ph.D. in earth and planetary sciences from Harvard University. He specializes in impact cratering processes produced when asteroids and comets collide with planetary surfaces. Kring is perhaps best known for his work with the discovery of the Chicxulub impact crater, which he linked to the K-T boundary mass extinction of dinosaurs and over half of the plants and animals that existed on Earth 65 million years ago. He has explored how impact cratering may have affected the early evolution of the Earth-Moon system. That work includes a decade-long campaign to test the lunar cataclysm hypothesis and the realization that the process affected the entire inner solar system. Kring developed an impact-origin of life hypothesis that suggests the intense period of impact bombardment created vast subsurface hydrothermal systems on Earth that were crucibles for pre-biotic chemistry and provided habitats for the early evolution of life. Dr. Kring also led a joint academic-industry-NASA design team for a robotic lunar lander and rover system that can be deployed anywhere on the lunar surface. He is particularly interested in the interfaces between science, exploration, and operations, to ensure our nation's exploration beyond LEO maximizes productivity while enhancing safety and efficiencies during robotic and crew operations. He trains astronauts how to work on planetary surfaces, whether that be on the Moon, NEA, or Mars. Participation instructions if you cannot attend in person:

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Almost submerged under Mare Imbrium basalt

Lunar mare basalt flows partially cover a crater. LROC NAC M186105790L, LRO orbit 12504, March 11, 2012; under a high Sun (incidence angle 17.75°) field of view 580 meters, resolution 1.03 meters from 131.69 km [NASA/GSFC/Arizona State University].
Sarah Braden
LROC News System

A crater (located at 17.331°N, 326.544°E) is almost entirely submerged by mare basalt. The remains of the crater indicate that the original crater was about 650-700 meters in diameter. Along the interior crater wall there are materials of different reflectance: high reflectance where boulders cover the crater wall, and low reflectance where mare basalt has flowed down the wall. The relatively low incidence angle of this image, ~18°, makes it easier to see differences in the reflectance of materials. The mare basalt flows filled the crater interior and left a mantle of mare material on the walls. It is unclear if the boulders are from the original crater wall, or if they are boulders from the basalt flow created as the edges of the flow erode away.

Even when mare basalt flows completely submerge a crater evidence of the crater rim can persist. These are called ghost craters (and you can read more about them HERE).

The crater in the Feature Image is east of another mostly submerged crater, T Mayer W (see the WAC context image below). The eastern rim of T Mayer W is the most prominent section above the mare basalt flows. Areas of high reflectance in the WAC context image are actually rays of ejecta from the crater Copernicus, which is more than 470 km away. These rays are an excellent example of how impact processes can effect the geologic context of a site even from a great distance. 

The white box contains the crater in the LROC Featured image released January 24, 2012. LROC Wide Angle Camera (WAC) 100 m/pixel mosaic [NASA/GSFC/Arizona State University].
Explore the entire LROC NAC, HERE.

Related Images:
Young and Old
Ghost crater in Mare Imbrium
The Ghosts of Mare Fecunditatis
Ghost Crater in Southern Mare Crisium

48 Years of memories of Alphonsus and Ranger 9

Alphonsus crater, at "dead center" of experienced amateur observer and Fayetteville, North Carolina newspaperman Johnny Horne's 5 inch reflector, Saturday evening, January 19, 2013 [Fayetteville Observer].
Johnny Horne
Fayetteville Observer

Last Saturday night I was at my telescope trying some photographic techniques on the moon using a 5-inch refractor telescope. .

I was photographing the large lunar crater Alphonsus which was just coming into sunlight, its central mountain peak casting a  shadow across the crater floor.

The 67-mile wide Alphonsus was one of the first lunar craters I could identify through my small telescope as a child in the 60s…finding it with the aid of a moon map in Sky and Telescope magazine. My interest in astronomy was fueled, as was the case for so many of my generation, by the US space program…both manned and unmanned.

One evening in March 1965 I was watching the evening news, specifically a story about one of the Ranger moon probes.

Alphonsus crater in a monochrome (689 nm) mosaic stitched together from eight sequential orbital observations of the LROC Wide Angle Camera in 2010. The March 24, 1965 impact site of Ranger 9 (captured at very high-resolution by LROC below - 12.8288°S, 2.3919°W) is marked by the arrow [NASA/GSFC/Arizona State University].
The Ranger probes, unlike later robotic probes that would soft land on or orbit the moon, were designed to impact the lunar surface…not so much a landing site as a smoking hole in the moon…

They would be taking pictures and sending them back to Earth right up until  impact.

That’s if they even made it to the moon.

Read the full article, HERE.

This exceptionally detailed photograph of the impact site of Ranger 9 on the floor of Alphonsus appears to include an inner disk of darker material perhaps 10 meters across. LROC Narrow Angle Camera (NAC) observation M170579736R, LRO orbit 10272, September 13, 2011; angle of illumination incidence 16.1° at 49.6 cm per pixel resolution from 44.64 km [NASA/GSFC/Arizona State University].

The proper course for lunar exploration (1965)

MOLAB with side-mounted drill and Apollo LEM as conceived in 1964-1965. The MOLAB would have arrived on the moon ahead of the piloted LEM on an unmanned LEM Truck [Bendix/NASA].
David S.F. Portree
Beyond Apollo

For a time, Thomas Evans headed up the Advanced Lunar Missions Study Program in the NASA Headquarters Office of Manned Space Flight. By the time of the 11th Annual Meeting of the American Astronautical Society (AAS) in May 1965, however, he had retired from NASA and become a farmer in Iowa. This gave him the freedom to speak his mind about what he felt were the Apollo Program’s shortcomings.

Evans told assembled members of the AAS that “the idea of a manned [landing] on the moon was so spectacular. . .that [it] dominated most pronouncements and thoughts on the space program.” He argued, however, that this objective had “too much the flavor of a stunt to be the final goal of a $20 billion national effort.” Evans maintained that
[Our] situation today is comparable to one which might have occurred during the railroad building era in America a century ago. It is as if the federal government had invested vast sums in the construction of the first railroad spanning the North American continent, but had procurred only a single engine and caboose. . . The first crossing by that engine and caboose would have been a major milestone in man’s progress and would have been greeted with enthusiasm and applause. But then those responsible for the program would have faced a major decision. . .Should the project be stopped? Should the engine-caboose be run repeatedly back and forth across the Continent to constantly remind the world of our great achievement? Or should a further modest investment be made in. . .some freight and passenger cars, to convert the system into something of practical value? Only the last solution would have been tenable then, and only a similar constructive approach would seem acceptable now.
 Evans argued that the Saturn rockets and Apollo spacecraft NASA had under development would provide “an excellent base upon which to build a broad program of manned. . .lunar exploration beyond the first landing.” Evans pointed to statements by President Lyndon Baines Johnson and Vice-President Hubert Humphrey which he said made clear that “the United States fully intends to explore the moon, not merely to visit it.” He also noted that NASA expected to be able to launch six Saturn V rockets per year beginning in 1969.

Read the full article, HERE.

Wednesday, January 23, 2013

Cislunar transportation: the space trucking system

The concept of the way-station could be extended from cislunar space to Mars or elsewhere in the solar system, as needed For AIAA gathering in 2012, a lunar lander departs from L2 [John Frassanito & Associates].
John K. Strickland
The Space Review

Many people wonder what all the fuss is all about when they keep hearing the phrase “cislunar architecture.” Many of us are using the phrase to refer to what is essentially a space trucking system, with the equivalent of truck stops and cargo loading yards (freight terminals). Lets use the trucking analogy to explain what we are talking about.

You do not use an expensive truck to carry a load just a single time, and then immediately send the truck to the junkyard to be scrapped. Trucking businesses could not operate this way. Some truck cab and trailer combinations today are probably worth close to a quarter million dollars new. Some cabs alone are close to $100,000 used. Most of the current rockets used today cost over $100 million, so large rockets can be up to 1,000 times more valuable than a tractor-trailer, yet all of them smash into the ocean or desert and become scrap metal after just one flight.

For rockets that take off from the ground, one obvious way to allow re-use is for them to land on the ground intact. SpaceX and some other companies are trying to do just that. Quite a few rockets have now accomplished short flights and landed again safely. Without wings, the landings must be vertical. Re-use with a vertical landing was first done by the DC-X at White Sands on September 11, 1993.

For rocket vehicles in space, the problem is different. We do not want to bring the vehicle back to the ground to refuel, since it is extremely costly to get it up into space in the first place. Once it is in orbit, we want to be able to re-use that vehicle in space over and over again.

Read the full article HERE.

Bullialdus Central Peak Oblique

The central peak of Bullialdus rises above the crater floor with the crater wall in the background. LROC Narrow Angle Camera (NAC) oblique (63.36° slew from nadir) M1099038207LR, LRO orbit 14313, August 8, 2012 (north to the left) resolution in foreground 2.31 meters from 73.65° over 20.96°S, 331.93°E [NASA/GSFC/Arizona State University].
Sarah Braden
LROC News System

Bullialdus is a complex crater located in the western part of Mare Nubium, at 20.7°S, 337.8°E (60.7 km diameter). Like all complex craters, Bullialdus has terraced inner walls and a central peak. The Featured Image shows an oblique view, taken from the West looking east at the eastern crater wall (north is to the left). The central peak towers 1.1 km above the flat crater floor. This NAC pair was taken while LRO was ~74 km above the lunar surface. This central peak may hold clues to the composition of materials deep within the Moon's crust.

Large complex craters excavate material from great depths in the lunar crust. The central peak is formed shortly after the bolide impact. While material is excavated and ejected to form the crater cavity, the ground at the center of the impact elastically rebounds after the shock and pressure. The material in the central peak originates from the deepest point in the lunar crust compared to the ejecta and rim material. These central peaks give scientists an opportunity to study the composition of the lower crust and upper mantle in order to understand how planets form and evolve over time.

LROC Wide Angle Camera (WAC) 100 meter per pixel mosaic of Bullialdus [NASA/GSFC/Arizona State University].
While the circular shape of the crater rim is degraded by slumping, the morphology of the crater's ejecta blanket is still visible. The persistence of the ejecta blanket morphology is an indicator that helps scientists estimate the age of the crater. Since the ejecta blanket hasn't been destroyed by subsequent impacts (micrometeorites and larger bolides), it means that Bullialdus is Eratosthenian in age (somewhere between 1.1 and 3.2 billion years old). You can compare the differences between Bullialdus and the crater Tycho, which is only 110 million years old. In the WAC context image (above) and digital terrain image (below) a smaller crater can be seen along the southeastern rim of Bullialdus. This crater (Bullialdus A) is clearly older than Bullialdus since ejecta from Bullialdus partially fills the interior of Bullialdus A. Bullialdus A is also non-circular in shape and it may have been deformed by the impact that created Bullialdus.

Colorized topography of Bullialdus [NASA/GSFC/Arizona State University].
Explore the entire oblique NAC, HERE.

Related Images:
New oblique view of Tsiolkovskiy Central Peak
Aristarchus Cobra Head

Central Peak of Bullialdus Crater
Southside, Aristarchus Crater
Tycho Central Peak Spectacular!
Aitken Central Peak, Seen Obliquely

Tuesday, January 22, 2013

Conjunction of Jupiter and the Moon

The Moon could be seen literally sliding under the Moon until moonset on the eastern seaboard of the U.S., Tuesday morning, January 22. 'jimnista,' contributor to the Universe Today photostream on flickr added the image above, a combination of two images to compensate for over exposure. It was the closest line of sight conjunction before 2026.

Monday, January 21, 2013

The Mona Lisa test for LADEE communications

The laser communications link between Goddard Space Flight Center and the Lunar Reconnaissance Orbiter (LRO) is already a record-breaker. More information has been returned to Earth from LRO through the high-capacity of laser light than all other deep space missions combined.

Later this year, the last of the original Constellation unmanned precursor missions, NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) will be launched from Wallops Island. The success of this small but advanced lunar atmosphere explorer will depend on its laser link. It's integral to its efficient mission design.

As a demonstration and test of that link, NASA recently put its nearly four year old laser link with LRO through its paces, beaming up and returning a facsimile of Leonard da Vinci's Mona Lisa.

Why the Moon looms large on the horizon: Binocular disparity as an explanation for the moon illusion

Is the Moon really larger at the horizon than overhead, or is this an illusion, created in our heads? [Photograph by Robert Arn, AstroArn Photography].
Joseph Antonides, Toshiro Kubota

We present another explanation for the moon illusion, in which the moon looks larger near the horizon than near the zenith. In our model, the sky is considered a spatially contiguous and geometrically smooth surface. When an object (like the moon) breaks the contiguity of the surface, humans perceive an occlusion of the surface rather than an object appearing through a hole. Binocular vision dictates that the moon is distant, but this perception model dictates that the moon is closer than the sky. To solve the dilemma, the brain distorts the projections of the moon to increase the binocular disparity, which results in increase of the angular size of the moon. The degree of the distortion depends upon the apparent distance to the sky, which is influenced by the surrounding objects and the condition of the sky. The closer the sky appears, the stronger the illusion. At the zenith, few distance cues are present, causing difficulty with distance estimation and weakening the illusion.

Read the research paper, HERE.

News story with commentary from MIT: "Moon illusion: New theory reignites debate over why Moon appears larger near the horizon," The Physics arXiv Blog, January 17, 2013

Full Moon rises over the ruins of the Temple of Poseidon, Cape Sounion, 69 km south-southeast of Athens, southernmost tip of the Attica peninsula in Greece. Seventeen sequential images by John Doukoumopoulos, June 18, 2008 [Lunar Picture of the Day (LPOD), June 20, 2008].

Thursday, January 17, 2013

Channels and fractures at Anaxagoras

Stratigraphic relationships within impact melt deposits may be discovered with diligent observation. LROC Narrow Angle Camera (NAC) observation M185971152L, LRO orbit 12485, March 9, 2012, Field of view roughly 1.8 km, angle of incidence 73.05° at 1.75 meters resolution from 179.28 km [NASA/GSFC/Arizona State University].
Lillian Ostrach
LROC News System

Stratigraphic relationships in impact melt deposits are not always easy to find, but careful observations of the LROC NAC images provide the perfect opportunity to search! Yesterday's Featured Image presented overlapping distal margins of melt and "bathtub rings" on the northern wall of Anaxagoras crater. Today's Featured Image highlights another stratigraphic relationship in the southwestern portion of the melt pool in Anaxagoras (73.271°N, 349.033°E). Along with the typical fractures near the melt boundary interpreted to be the result of cooling and contraction, there is an impact melt-covered mound (opening image, right) with boulders eroding out from the steepest slopes. At the bottom of the image, there are two parallel troughs that cut through pre-existing material. These troughs probably represent impact melt-carved channels, where melt flowed from higher elevation to lower elevation and carved out a pathway.

But which way did the melt flow? Looking carefully, there are faint linear depressions extending from the top of the image to the channels, suggesting that flow progressed from the bottom right of the image toward the top left. These linear channels are very shallow, barely visible compared to the visible fractures. The shallowness of these channels possibly result from later movement of melt. The fractures cross-cut the shallow channels, indicating that the channels are older than the fractures.

LROC WAC monochrome mosaic of the rubbled interior of Anaxagoras crater (73.458°N, 349.934°E, - 52 km diameter). Location of the area shown at high resolution in the LROC Featured Image released January 17, 2013 noted by the yellow arrow [NASA/GSFC/Arizona State University].
However, note the sharpness of the fractures. The fractures that curve toward the mound and closest to the deeply carved channel troughs have a smoothed appearance when compared to the fractures closer to the top center of the image. Thus, there are two families of fractures, suggesting that perhaps the channels flowed into this area on top of a lightly-crusted pond (reasoning for shallow channels remaining) that then continued to cool, forming the first set of fractures. As the melt cooled more, maybe the second set of fractures formed if the second set is related to cooling.

Perhaps the second set of fractures formed as an internal plumbing system failed, or maybe an injection of hotter melt into this area (beyond the opening image frame) occurred that inflated the crust of the cooling melt and shallowed both the channels and first set of fractures. Without additional detailed observations, including NAC-derived topography, the stratigraphic story of melt movement and cooling concludes with at least two (three?) endings. However, the presence of small pits in the youngest fractures may provide supporting evidence for the plumbing or inflation story, because pits and fractures in the pond interior (away from the melt boundaries) are probably related to a lava tube-like underground melt plumbing system, a hypothesis supported by many NAC images at many different locations on the Moon.

What do you think? After studying the full LROC NAC image, HERE, do you have supporting evidence for the conclusion to the stratigraphic story of melt in this portion of Anaxagoras?

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