Landing Site at Tycho North (Science Concept 7)

A Ready-Made Landing Site?   One among many 'flash-frozen' impact melt ponds, a flow over the rugged ejecta immediately north of Tycho crater halted in place 109 million years ago. This one is 800 meters long along its north-south axis, and apparently level, nested about half the distance between the 1968 unmanned Surveyor 7 lander and a geologically interesting breach on Tycho's rim. LROC Narrow Angle Camera (NAC) observation M111668133RE, LRO orbit 1590, October 31, 2009; resolution 51 cm per pixel, angle of incidence 47.88° photographed from 49.39 km [NASA/GSFC/Arizona State University].

Second in a series of posts highlighting newly-proposed lunar landing sites selected to address high-priority science goals - from a remarkable landing site study published by the Center for Lunar Science and Exploration (CLSE):

Another image, less close-up, of the proposed 'Tycho North' landing zone, at slightly less granular resolution (0.65 meters per pixel), the nominally level melt pond is visible in greater context, nested in the rough and debris-strewn Tycho ejecta. The local slope runs from east to west but, overall, lower north and away from 86.2 km Tycho. From a mosaic, LROC NAC M106950070LR, spacecraft orbit 901, September 7, 2009; from 63.18 km altitude, angle of incidence 45.55° [NASA/GSFC/Arizona State University].

Joel Raupe
Lunar Pioneer

On February 5 we discussed a proposed landing site in Amundsen crater selected to support "Science Concept 4" as outlined in the commissioned National Research Council (NRC) study The Scientific Context for the Exploration of the Moon (2007).

In this second of a planned series we move to an area north of Tycho visited by Surveyor 7 in 1968. Material from the region was also very likely sampled by Apollo 17 in 1972, as Eugene Cernan and Harrison Schmidt explored Tortilla Flats in Taurus Littrow Valley, 2200 kilometers away.

While working with those same samples at the Johnson Space Center's Lunar Sample Laboratory Facility, Jack Schmidt soon helped estimate the age of samples collected at the base of South Massif directly opposite from Tycho at 109 million years. When the Tycho event happened, only 44 millions years remained before a similar impact ended the long reign of dinosaurs on nearby Earth. When offered as an example of the Moon's young craters the immense differences between terrestrial and lunar timescales and surface preservation rates are made stark. Such differences make it easy to forget that Earth and Moon have essentially shared the same location in the inner Solar System for 4.5 billion years (with Earth being a larger target and deeper gravity well). A study of the impact history and space weathering environment preserved on the Moon is a study of a much better preserved record of Earth's history.

This landing zone was proposed to address "Science Concept 7," a site that first presented to the Lunar and Planetary Science Conference in 2012 (Abstract #1387), from work produced by the Lunar & Planetary Institute Summer Intern Program the previous year. More detail emerged in the final CLSE landing site study of each of the NRC's 2007 lunar science goals, last fall. The LPSC 2012 abstract and contribution to the final CLSE study are credited to director David A. Kring and LPI 2011 interns Sarah Crites, Agata Przepiórka, Stephanie Quintana, Claudia Santiago and Tiziana Trabucchi.

"Science Concept 7" outlined in the National Research Council's NASA-commissioned Scientific Context for the Exploration of the Moon (2007). The Center for Lunar Science and Exploration (CLSE) released "A Global Lunar Landing Site Study to Provide the Scientific Context for the Exploration of the Moon" in late 2012, an exhaustive study of possible landing sites selected to address NRC 2007 lunar science concepts and goals [CLSE/LPI/NLSI].

The sites appearing in the new CLSE study might be broadly separated into two sets, ranked lists of many possible landing sites picked to fulfill all or overlapping part of the goals under the Science Concepts or individual targets picked in hopes of addressing all goals within one Science Concept and possibly overlapping with one or more of the other Concepts.

In other words, the ranks of possible landing sites in the new study range from those picked to accomplish much within practical, logistical and budget constraints over the next two decades to a long list of sites that may require 50 to 100 years to directly sample, along with a few lists falling somewhere in between. This might be a reflection of the political changes occurring over the years since the study began, when renewed exploration and establishing an extended human presence on the Moon went from being National Space Policy to falling by the wayside.

The new study is highly useful, regardless. Along with the Lunar Impact Crater Database, an even more detailed picture of the origins, ages and compositions of the Moon's complex features has been coming into focus, reflecting the astounding range of detailed information about the Moon collected in recent years.

Another full resolution LROC NAC view of the proposed landing zone, from a mosaic of the left and right frames of LROC NAC observation M111668133LR, LRO orbit 1590, October 31, 2009; incidence angle 47.82° from 49.39 km [NASA/GSFC/Arizona State University].

Since the goal is to establish definitive baselines, the actual ground truth of the upper few centimeters of the Moon's surface, why land near Tycho, the 86.2 km-wide astrobleme (41.49°S, 348.23°E) that is so much younger than its counterparts from earlier eras that have long faded into the albedo background? As it turns out, it's precisely because of such notably pristine.conditions, a comparatively youthful impact upon a region older than Mare Imbrium, that led Kring and his colleagues to seek this place out - along with proximity with Surveyor 7.

Understanding the dynamics of the upper few centimeters of the Moon's surface, most of which is turned-over, or "gardened" every couple of million years - involves more than dust mitigation or the charging and levitation of sub-micron dust as it interacts with radiation from the Sun and deep space or the Moon's nested crustal magnetic fields. Researcher will need a better understanding of this blasted layer of fine particles on wildly different timescales.

A really outstanding oblique view shows the proposed Tycho North Landing Zone from up over a spot 100 km west of Tycho, offerring even more perspective on the complex terrain surrounding the target melt pond (near center). Inset (see rectangle below) from an oblique (59° east of nadir) LROC NAC mosaic of from LROC NAC M1101317790, LRO orbit 14632, September 3, 2012 [NASA/GSFC/Arizona State University].

Thumbnail of the entire LROC NAC M1101317790RLR mosaic shows the area of the target melt terrace (the field of view in the immediately preceding full-resolution crop is framed by the yellow rectangle) in relation with Surveyor 7 and the rim of Tycho, 20 km south (to the right). Incredibly - at full resolution - the Surveyor 7 lander is actually visible in the full image. A proposed science station on the rim of Tycho is just outside this view at lower right [NASA/GSFC/Arizona State University].

Up, over and just beyond Tycho's 1200 meter high rim, the proposed LZ pictured above sits roughly at 620 meters elevation above the lunar geode (near 41.49°S, 348.233°E), the Moon's mean elevation, just out of sight from the sharp 800 meter drop down the crater wall (check this). The familiar crater's complex ejecta blanket extends 110 km from the central peaks, and its famous rays, visible to the naked eye, extend past 2000 km.

Beyond the debris piled high on the Tycho rim, the area of interest north by northwest of the crater, is characterized by slopes from 4.5 to 6° - safe for manned and unmanned landers. The specific Landing Zone is approximately 20 km from the rim fall off, where ancient pre-impact regolith appears to be exposed in layers visible in LROC NAC photography.

Because Tycho excavated pre-Imbrium nearside Southern Highlands, "any paleoregolith layers in Tycho's walls will also have a pre-Imbrium age," Kring and his colleagues note.

"Tycho's crater walls are the best target for sampling," though the upper reaches of the mountainous rim between the landing zone and the crater wall retain slopes greater than 25° "a navigable route to access layered deposits can probably be found."

Clementine multi-spectral mosaic color-coding overlaid on LROC Wide Angle Camera (WAC) 100 meter global mosaic shows the Science Concept 7 proposed landing site (arrow) is near the border between two widely different surface compositions [NASA/GSFC/DOD/ASU].

"The site provides access to regolith produced from substrates of different compositions (see image above)," from the coherent melt pond of the landing site itself to "rubbly ejecta... in a highlands area far from" the unique Procellarum, Potassium and Rare Earth (PKT, or 'Procellarum KREEP') terrain, covering so much of the nearside's west quarter.

Because the Tortilla Flats formation, sampled by Apollo 17, and nearby Surveyor 7 sampled materials related to the Tycho impact event "we can leverage these previous missions to compare properties of regolith of the same age formed from different types of ejecta."

Fifty km-wide LROC WAC field of view barely hints at the complexity of the terrain around the rim of Tycho. The suggested "Science Concept 7" landing site is an equidistant 10 km 'walk-back' distance (as the orbiter flies) from the 1968 landing site of Surveyor 7 (the last unmanned U.S. lander) and a suggested science station, a rare, dramatic breech in the sharp wall of the 'young' 109 million year old crater. The peninsula of melt piled into a comma below and to the right of Surveyor, was shown at very high resolution in "Giant Flow of Tycho Impact Melt," LROC Featured Image released August 14, 2012. LROC WAC (M168272917-9335CE) monochrome (643nm) mosaic   [NASA/GSFC/Arizona State University].

One of the best all-around LROC NAC images of Surveyor 7 (below left, arrow, and at full-resolution in the inset), from M150598504L, LRO orbit 7327, January 25, 2011; spacecraft and camera slew -15.17° from nadir, resolution 0.52 meters per pixel, angle of incidence 69° from 45 km. This roughly 300 meter wide field of view also includes another Tycho melt pond, the landing site Surveyor project manager Gene Shoemaker had hoped for as eventual landing site for this last vehicle of the program. The tripod lander's square sail, atop a supporting mast, casts a distinctive shadow [NASA/GSFC/Arizona State University].

Nearby Tycho's Rim - A possible breech in Tycho's high rim - within walking distance of the proposed Landing Zone, in the opposite direction from Surveyor 7 - may provide sampling access to the layered regolith visible above center-right. This angled corner on the north-northwest rim of Tycho was clearly modified very soon after the crater formed. Whether the slope below is too great to allow men and machines invaluable direct access to Tycho's equally interesting interior is still uncertain. LROC NAC mosaic M160029952LR   [NASA/GSFC/Arizona State University].

Some perspective to the proposed Science Concept 7 science station, on Tycho's rim (arrow) and the crater rim, wall and floor. Melt ponds dot the region. (In this oblique view, the landing zone and Surveyor 7 locations are outside this frame.) Still from video prepared from JAXA photography and data collected by the SELENE-1 (Kaguya) [JAXA/SELENE].

Establishing the rate and manner space weathering leads to the optical maturing (OMAT) of the Moon's surface will help researchers understand processes ranging from the interaction of reactive dust with crustal magnetism - the age and deposition rates of the Moon's swirl phenomena - the deposition of lunar volatiles and tighter estimates of the age of craters between one and two billion years old, past the time needed for optical maturity to do its work. 

Tycho, a recent rich excavation of the Moon's nearside Southern Highlands, and sights along a potentially valuable ingress to the crater's interior demonstrating the potential value of a single rather multiple expeditions. LROC WAC mosaic stitched from four sequential orbital overflights  LROC WAC (M168272917-9335CE) monochrome (643nm) mosaic   [NASA/GSFC/Arizona State University].

Remote sensing maturity maps hint the proposed landing site is characterized "by both very immature and intermediately mature soils," according to Kring and colleagues, "providing an opportunity to see the evolution of space weathering processes."
 
Proximity with Surveyor 7, about 20 km away, in the opposite direction from Tycho's rim, allows study of a known surface, and for a known amount of time (since 0600 UT, 7 January 1968), a stated goal in the NRC's 2007 commissioned report.
 
It's hoped the 20 km distance from the proposed landing site will prevent Surveyor 7, as a valuable 'long-duration exposure facility," from being undermined like Surveyor 3, ultimately swept clean by the descent of Apollo 12 only 183 meters away in 1969.Surveyor 7 may provide a "more pristine" baseline for measuring short-term space weathering.
 
The Tycho North landing site clear of any known crustal magnetism, free of space weathering processes both accelerated and slowed, as they appear to have been at Reiner Gamma, for example. Samples should therefore be "better representative of the lunar highlands."
 
The rate of solar-wind production of volatiles "can also be nicely calibrated here," Kring and his colleagues have noted, since "the exposure age is known and the orbital relationship between the Moon and the Sun is unlikely to have changed significantly over that period."
 
Chemical traces of the object that created Tycho Crater may be be found in the melt-rich rocks at the landing site, along with the shattered pieces of more distant and much older events in the 'recently' exposed paleoregolith uplifted in layers at Tycho's rim.

Some Related Posts:
Amundsen crater and the CLSE Landing Site Study (February 5, 2013)
Rippled Pond on Tycho's Wall (September 13, 2012)
Breached Levee at Tycho (September 11, 2012)
Giant Flow of Impact Melt (August 14, 2012)
River of Rock (June 20, 2012)
View from the Other Side (May 21, 2012)
Impact Melt Fingers (May 8, 2012)
Melt on a Rim (May 3, 2012)
Tycho Central Peak Spectacular (July 5, 2011)
Chaotic crater floor in Tycho (June 19, 2011)
Polygonal fractures on Tycho ejecta deposits (June 15, 2011)
Ejecta on slumped wall of Tycho (December 9, 2010)

When the Moon is full, Tycho's bright ray system is among the few lunar features visible to the naked eye. A testimony to its youth, a low degree of steady space weathering when compared to hundreds of similar but older crater,s from before the time when dinosaurs ruled the earth. The "miracle boys of Minsk" (Astronominsk) captured this local late morning image of Tycho, part of a full disk monochrome mosaic, captured from Belarus, September 20, 2010.  One of their fabulous color images of Тихо can be viewed HERE [Astronominsk].

New 3D CLSE lunar flyover video: Schrödinger basin

David A. Kring, Ph.D.
Center for Lunar Science & Exploration (CLSE)

The Center for Lunar Science and Exploration added another video to its Atlas of Lunar Flyovers. In this new addition, we explore the floor of the Schrodinger basin.The direct link to the new flyover is HERE.

The Moon’s Schrödinger basin is the best preserved impact basin of its size.  Its broad flat floor offers several safe landing sites and the geology within the basin is extraordinary.  The two highest science priorities and over half of the science objectives outlined in the National Research Council (NRC) report The Scientific Context for Exploration of the Moon (2007) can be addressed with field studies and samples collected in Schrödinger basin.

Schrödinger basin CLSE landing study 'Site B' (yellow ellipse), well within the 10 km safety 'walk-back' distance of the an unnamed 6.8 km Copernican Age crater that presumably excavated deep into the basin's intact peak rings, depositing valuable samples near the crater rim. (Further details on this site will be the subject of a future post.) The site, in context with the larger basin, is marked with a yellow arrow below. LROC Wide Angle Camera (WAC) monochrome (643nm) observation M169698283C, LRO orbit 10142, September 3, 2011; angle of incidence 72.67° at 81.3 meters resolution, from 58.66 km [NASA/GSFC/Arizona State University].

The video highlights three features in the basin.  It begins with a flight along a fracture in the basin floor towards an immense volcanic vent of pyroclastic material.  Because of the in situ resource utilization (ISRU) potential of the pyroclastic material, this vent was a target of the Exploration Systems Mission Directorate (ESMD) portion of the Lunar Reconnaissance Orbiter (LRO) mission.

The notably darker material surrounding Schrödinger basin's distinctive pyroclastic vent. Another landing site (green arrow, in an image showing the entire basin interior floor) is proposed near upper center right in this oblique LROC Narrow Angle Camera (NAC) field of view. LROC NAC mosaic M121415248LR, LRO orbit 3026, February 21, 2010; angle of incidence 81.66° (spacecraft slew -65.65° off nadir) rough resolution 3.7 meters from 53 km [NASA/GSFC/Arizona State University].

The flyover then turns towards the towering and mountainous peak ring that contains rock exposures of material uplifted from the mid- to lower-crust by the basin-forming impact event.  The flyover then sweeps back towards the pyroclastic vent over an intervening plain of melt-bearing impact lithologies.  Samples of that material can be used to determine the age of the Schrödinger basin and, thus, help test the lunar cataclysm hypothesis.

Related Posts:
Amundsen crater: CLSE lunar landing site study (February 5, 2013)
Scarps in Schrödinger (September 28, 2011)
Sampling Schrödinger (August 17, 2011)
A review of all things Schrödinger (August 31, 2010)
LOLA: Schrödinger basin (July 17, 2010)
Craters on the Schrödinger pyroclastic cone (April 24, 2010)

LROC WAC 100 meter monochrome global mosaic shows the 312 km-wide Schrödinger basin, a prominent feature of the far southern far side latitudes and stand out increasingly as a location where many high-priority lunar exploration science goals might be accomplished. The area includes smooth and rough plains, basin wall material, hummocky terrain, intact peak rings, mare, dark explosive volcanic material and ridged terrain. CLSE Landing Site Study Site A (green arrow) and Site B (yellow arrow) are shown at much higher resolution in the images further above [NASA/GSFC/Arizona State University].

Deadline approaching for Lunar Exploration Summer Intern Program

Were these boulders on the west slope, and the rocky outcrop above on Hausen crater's central peak, excavated from the Moon's mantle - rebounding from below the Moon's megaregolith and crust? The CLSE Landing Site Study - the work of students in the CLSE Lunar Exploration Summer Intern Program - estimate the Hausen impact as perhaps the Moon's deepest natural excavation. LROC NAC M105100555LR, orbit 643, August 16, 2009; resolution 49 cm from 41.38 km [NASA/GSFC/Arizona State University].

David A. Kring, Ph.D.
Center for Lunar Science & Exploration

The deadline is approaching for applications to the 2013 edition of the Lunar Exploration Summer Intern Program.

Over the previous five summers, graduate student teams conducted a global survey of lunar landing sites that are suitable for meeting the objectives in the NRC (2007) report "The Scientific Context for Exploration of the Moon."  

A summary of those results was recently published (http://www.lpi.usra.edu/nlsi/CLSE-landing-site-study/).

During the summer of 2013, students will generate a detailed assessment of one or two high-priority landing sites identified in that report. This summer study will utilize the latest lunar data (e.g., M3, LOLA, LROC), explore potential traverse routes and stations, and identify hurdles that mission architects will need to address.

Additional details about the program and application process can be found HERE.

The application deadline is March 1, 2013. Email: kring@lpi.usra.edu

USRA - Lunar and Planetary Institute
3600 Bay Area Blvd.
Houston, TX  77058-1113
(281) 486-2119
 
Research publications: http://www.lpi.usra.edu/science/kring/research.shtml

Amundsen crater and the CLSE Landing Site Study

Embracing the Void - A contributing team to A GLOBAL LUNAR LANDING SITE STUDY to PROVIDE the SCIENTIFIC CONTEXT for EXPLORATION of the MOON (CLSE/LPI/NLSI, 2012) suggests a landing site on the floor of Amundsen crater, in the Moon's far south, on a well-lit area nestled on the edge of a permanently shadowed region (PSR) - an "integrated site," carefully selected to efficiently address each of the priorities outlined by the National Research Council under "Science Concept 4" in 2007.   LROC Narrow Angle Camera (NAC) mosaic, LROC QuickMap, 16 meters resolution [NASA/GSFC/Arizona State University].

First in a series of posts highlighting newly-suggested landing sites selected to address high-priority science goals - from a remarkable lunar landing site study published by the Center for Lunar Science and Exploration:

An area chosen to groundtruth, to baseline the life cycle and retention of volatiles on the Moon is also close to a prominent central peak which may present accessible samples of the Moon's megaregolith, crust or mantle. To the north, the north wall and floor of Amundsen remains in perpetual shadow. Maximum 80 meter resolution section from LROC Wide Angle Camera (WAC) monochrome (643nm) observation M139410549ME, LRO orbit 5678, September 18, 2010 [NASA/GSFC/Arizona State University].

Joel Raupe

Lunar Pioneer

In November the Center for Lunar Science and Exploration, a distinguished science team sponsored by the NASA Lunar Science Institute (NLSI), released a set of comprehensive lunar landing site studies fashioned carefully on the lunar Science Concepts and Goals outlined in the National Research Council's influential 2007 report The Scientific Context for the Exploration of the Moon.

The last section of the eight-part study addresses the possibility of exploration and sample return from South Pole-Aitken basin and how sites selected there might fulfill all Science Goals outlined in the 2007 NRC report. Meanwhile, within the CLSE Landing Site Study, the section addressing NRC Science Concept 4 is directed at the important goal of gaining ground truth regarding the life cycle of volatiles on the surface of the Moon, and especially their retention in permanently shadowed cold traps near the north and south poles. Though a study for a potential New Frontiers-class mission to study lunar volatiles was included in the 2013-2022 Decadal Survey, it was not specifically included in recommendations for a South Pole-Aitken basin sampling mission and a new lunar geophysical network during the decade ahead.

The CLSE Landing Site Study recommendations, however, were constrained by many of the limits placed on a manned mission, both within and beyond the Constellation program, cancelled as the studies developed.

To groundtruth, so to speak, the real-time transport, loss and retention of lunar volatiles (e.g., water and hydroxyl molecules, neutral hydrogen or the exotic species tossed up by the LCROSS impact) the team working on NRC Science Concept 4 carried out a careful study of the north and south polar regions and, as announced originally at the 43rd Lunar and Planetary Science Conference, Amundsen crater emerged as one of the far south's most favorable locations. (The lunar north also had targets emerging from the data, more perhaps than in the south, we hope to also spotlight in near future.)

A refrain repeated often in the CLSE Landing Site Study was emergence of a many favorable targets, some familiar and some not. However, with budgetary stresses unlikely to disappear soon, identifying those areas presenting the greatest probability of addressing multiple science concepts, visiting as few landing sites as necessary, has become valued work. Beyond emerging as a bright target in remote sensing of volatiles, Amundsen presents the added virtue of being within South Pole-Aitken. Examples of targets addressing overlapping priority science goals also included Schrödinger basin and Antoniadi crater.

(The work continues. Just this past week the Center announced the availability of a web-based ArcGIS tool for evaluating SPA landing sites.)

Figure 4.25 from - "Science Concept 4: The Lunar Poles are Special Environments that may bare witness to the Volatile Flux over the latter part of Solar System history" (2012). The floor of Amundsen crater, Permanently Shadowed Regions (PSRs - dark blue) and sites where all five of "Science Concept 4" Science Goals, relating to lunar volatiles, might be met (light blue), together with proposed landing sites (stars) and science stations (circles). Radii of the 10 km "walk-back" distance, and 20 km, respectively, from each landing site are shown as solid and dashed lines. [LROC WAC/LOLA shaded relief - NASA/GSFC/ASU].

Students in the Lunar & Planetary Institute Summer Intern Program methodically attacked the puzzle of picking landing sites likely to provide important answers to the planetary science questions outlined in the NRC’s Space Studies Board 2007 report. Greatly simplified, locations satisfying NRC Science Concept 4 specifics were figuratively overlaid one upon another to further identify locations suited to multiple science goals.

Seeing in the Dark - (LROC QuickMap - South Pole orthographic projection) - the interior of Amundsen crater. LRO laser altimetry has now disclosed great detail within the Moon's Permanently Shadowed Regions (PSRs), and CLSE Science Concept 4 suggested landing sites concepts A and B straddle a boundary between well-lit zones of moderate temperatures and priority lunar volatile science stations in perpetual shadow, characterized by some of the Solar System's coldest temperatures. "Site A" is shown by the red cross, "B" by the yellow [NASA/GSFC/Arizona State University].

Located inside the 4.1 billion year old South Pole-Aitken impact basin, 105 km Amundsen is the youngest complex crater in the far lunar south, one of only three complex craters poleward of 80°S. Though formed in the late Nectarian its floor is consistant with the Imbrium peiord. LROC WAC monochrome (643nm) observation M139410549ME, LRO orbit 5678, September 18, 2010; resolution 80 meters per pixel from 57.37 km [NASA/GSFC/Arizona State University].

Straddling the 270th meridian east, at the boundary of the Moon's near and far sides, the area of interest at Amundsen is nominally within "line of sight" (under favorable libration) from Earth. Here the crater, its floor and eastern wall, are visible in reflected radar. From S-band (12.6 cm wavelength) radar view of the Moon's south pole obtained using Arecibo and Green Bank, available HERE. Yellow star marks "Site A." Data was acquired in 2005 and published in 2006, and "have a single-look spatial resolution of 20 meters per pixel" [NLSI/Cornell].

Over five summers successive groups of students worked on each of the 2007 Science Goals outlined by the NRC, as the economic, political and lunar science environment evolved around them.

The Constellation program was scrubbed, including the Altair lander, though the on-time and under-budget unmanned supporting missions already well-along in development survived. LCROSS and LRO, fortunately, thrived together, along with development of the ambitiously efficient precursors GRAIL and LADEE. As the momentum originally put into motion by Constellation and the aftermath of the Columbia accident finally experiences a kind of inevitable "heat death," however, the specifics of the future of U.S. unmanned exploration of the Moon is gravely in doubt. Notwithstanding a supposed plan to return astronauts to the lunar vicinity later in the decade, it's difficult to imagine how such a mission can improve upon the science returned by LRO.

That first summer the LPI interns began with data rooted still in the 20th century. Five summers later, fresh teams, focused on subsequent NRC Science Goals, were assisted with results from missions entirely rooted in the 21st century. They were fortunate enough to sample the first sips from a fire hose of data eventually returned from Japan’s Kaguya, India’s Chandrayaan-1, China’s Chang’E-1 and 2; along with results from LCROSS and, perhaps most important, the record-breaking data still coming down from the Lunar Reconnaissance Orbiter.

Constraints on a the starting prospect of manned missions to the Moon, those "sorties" seen as originating from "an extended human presence" at a permanent station on the rim of Shackleton crater, were lifted before the CLSE Landing Site studies were published. By the time of the study's release pinning NASA or Congress down on the ways and means of accomplishing lunar science seemed similar to keeping spaghetti on a fork. Nevertheless, if the only permanent legacy of the defunct Constellation program turns out to be studies like the one produced by CLSE, assisted by a swarm of well-managed and efficient unmanned spacecraft like LRO, it may very well prove to be worth every penny "wasted" on the Ares boosters and the Altair lander. (There are, of course, other windfalls worth mentioning beyond the scope of this Introduction.)

Science Concept 4 from "SCIENTIFIC CONTEXT for the EXPLORATION of the MOON (2007)." The Center for Lunar Science and Exploration methodically took on the task of using the latest data to begin suggesting landing sites to fulfill the National Research Council lunar science priorities, resulting in a remarkable report released in November 2012.

Their finished product speaks well for itself, and the editing and teaching skills of the Student Intern Program coordinators and study co-editors David A. Kring and Daniel D. Durda of the Lunar and Planetary Institute. A host lunar targets, many still unnamed, have augmented the 50 Constellation Regions of Interest.

“As this study unfolded, it became clear the Apollo landing sites, while completely reshaping our understanding of the solar system 50 years ago, represent only a tiny fraction of the lunar surface," Kring wrote last November.

"Other sites can reveal completely new details of lunar history and are, arguably, better sites for addressing the fundamentally important issues identified in the NRC's 2007 report.  This study asked a simple question, where on the lunar surface could the objectives in the 2007 report be addressed?

"Maps keyed to each of those objectives were created and, when those maps were stacked, several lunar surface locations popped out as the scientifically-richest landing sites."

Amundsen (r) in context with the far lunar south. LROC Quickmap, south pole orthographic projection at 500 meters per pixel resolution [NASA/GSFC/Arizona State University].

"Volatiles at the Lunar South Pole: A Case Study for a Mission to Amundsen Crater" (LPSC 2012, #1619), acknowledged the yeoman labor on addressing "Science Goal 4," fleshed out in depth in the CLSE Landing Site Study:

From  "Science Concept 4: The Lunar Poles are Special Environments that may bare witness to the Volatile Flux over the latter part of Solar System history."

"Amundsen crater, centered at 84.6°S, 85.6°E, is a complex, central-peak crater approximately 100 kilometers in diameter...the youngest south polar complex crater. Amundsen formed in the late Nectarian, but its floor has a crater density consistent with an Imbrium age. The entire crater sits within the South Pole-Aitken (SPA) impact basin, the oldest and largest discernible lunar impact crater.

"Approximately 9 percent of the interior of Amundsen is in permanent shadow and  approximately 6 percent of the interior satisfies all five of the NRC (2007) Concept 4 Science Goals. A 43 square kilometer region directly north of our proposed landing site is one such region in which all five Science Goals could be addressed.

We chose Amundsen crater because it has many easily-accessible sites that address all or most Science Goals (IV).

Figure 4.8 from "Science Concept 4: The Lunar Poles are Special Environments that may bare witness to the Volatile Flux over the latter part of Solar System history." shows areas in the vicinity of the lunar South Pole where all the priority questions related to NRC 2007 Science Goal 4 might be fulfilled. Addressing all these priorities obviously narrows the selection of landing sites down rapidly and makes Amundsen crater stand out.

A broad range of geologic features is also present within Amundsen; these include crater floor materials, crater walls, wall slumps from higher on the crater wall or rim and central peak material. It also contains many smaller craters with varying degrees of degradation. Sampling these various morphologies may place constraints on distribution of volatiles, partially addressing Science Goal 4a.

We identified two landing sites (A and B) on the floor of Amundsen crater lit up to one quarter of a lunation (Zuber et al., 2011). 

Those sites provide access to stations within (Permanently Shadowed Regions) while providing a base of operations in an illuminated region. Stations outside of PSRs can serve as experimental controls for the processes that affect volatile distribution within PSRs. Contrasts between the two regions can also be used to evaluate transport mechanisms. Remotely observed circular polarization ratios (CPR) (Zhang and Paige, 2010) also vary around both landing sites, providing an opportunity to ground-truth the global data set and test the effects of ground ice and surface roughness on those CPR values. Temperatures derived from the Diviner radiometer (Paige et al., 2010) also helped define station locations.

Temperature extremes at the Moon's south pole as detected by the The DIVINER Lunar Radiometer Experiment on-board the Lunar Reconnaissance Orbiter (LRO) shows the rapid temperature swing, within walk-back distance from a lunar lander, at the study's suggested landing sites at Amundsen (black arrow) [NASA/GSFC/UCLA].

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 http://www.lpi.usra.edu/nlsi/SPA_Basin_Landing_Site_DB/

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:

TO JOIN USING A WEB BROWSER: The slides and audio/video for this meeting will be presented using Adobe Connect. To join the meeting, connect HERE. (http://connect.arc.nasa.gov/nlsi_directors_seminar/)

TO JOIN USING A VIDEOCONFERENCING SYSTEM: Please RSVP to Ricky Guest (Ricky.Guest@nasa.gov) if you will be joining by Polycom or other standards based Video Teleconferencing System.

GRAIL twins coax out the Moon's deeper history of the solar system's early, pulverizing bombardment

GRAIL primary mission global gravity map, centered on 0°N, 355°E, from animation released Dec. 5, 2012. Science Visualization Studio (SVS), GSFC [NASA/JPL/MIT].

Jennifer Chu
MIT

Beneath its heavily pockmarked surface, the moon’s interior bears remnants of the very early solar system. Unlike Earth, where plate tectonics has essentially erased any trace of the planet’s earliest composition, the moon’s interior has remained relatively undisturbed over billions of years, preserving a record in its rocks of processes that occurred in the solar system’s earliest days.

Now scientists at MIT, NASA, the Jet Propulsion Laboratory and elsewhere have found evidence that, beneath its surface, the moon’s crust is almost completely pulverized. The finding suggests that, in its first billion years, the moon — and probably other planets like Earth — may have endured much more fracturing from massive impacts than previously thought.

The startling observations come from data collected by NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission. Since March, the mission’s twin spacecraft, named Ebb and Flow, have been orbiting the moon and measuring its gravitational field.

From GRAIL’s measurements, planetary scientists have now stitched together a high-resolution map of the moon’s gravity — a force created by surface structures such as mountains and craters, as well as deeper structures below the surface. The resulting map reveals an interior gravitational field consistent with an incredibly fractured lunar crust.

“It was known that planets were battered by impacts, but nobody had envisioned that the [moon’s] crust was so beaten up,” says MIT’s Maria Zuber, who leads the GRAIL mission and is the E.A. Griswold Professor of Geophysics in the Department of Earth, Atmospheric and Planetary Sciences. “This is a really big surprise, and is going to cause a lot of people to think about what this means for planetary evolution.” 

Zuber and her colleagues detail their findings from GRAIL in three papers published this week in Science.

GRAIL’s lunar gravity map has also revealed numerous structures on the moon’s surface that were unresolved by previous gravity maps of any planet, including volcanic landforms, impact basin rings, and many simple, bowl-shaped craters. From GRAIL’s measurements, scientists have determined that the moon’s crust, ranging in thickness from 34 to 43 kilometers, is much thinner than planetary geologists had previously suspected. The crust beneath some major basins is nearly nonexistent, indicating that early impacts may have excavated the lunar mantle, providing a window into the interior.

Lifting a veil: In addition to mapping the Moon's anisotropic gravity with unprecedented granularity, the GRAIL primary mission uncovered deeper, essentially vertical dyke structures hundreds of kilometers long, the existence of which had been erased at the surface [NASA/JPL/MIT].

To generate the gravity map, GRAIL’s two probes measure the changing distance between themselves as they orbit in tight formation around the moon. As one of the probes flies over a large mass, such as a mountain or dense, underground rock, the stronger local gravity will pull that probe ahead, widening the space between the two spacecraft. Scientists can translate this changing distance into a gravitational map, representing the gravity produced by both the surface structures and the interior.

To find the gravitational field for the moon’s interior alone, Zuber’s team used topographic measurements from another of their instruments, a laser altimeter aboard the Lunar Reconnaissance Orbiter, a separate spacecraft in orbit around the moon. The scientists calculated the gravitational field expected to be produced by the moon’s topography — its surface structures alone — then subtracted that field from the field measured by GRAIL.

“It’s essentially like removing a veil to reveal the gravity due to the inside of the planet,” Zuber says. “And when we saw those maps, we were just speechless.”

The GRAIL primary science mission also succeeded in definitively mapping the thickness of the Moon's outer crust, shown in another global animation centered over the thickest zones on the lunar farside. The South Pole-Aitken basin, oldest and largest identified impact at 4.1 billion years, hosts some of the thinnest outer crust. The mission has increased the likelihood that fragments of the Moon's deeper zones will eventually be found on the surface, excavated by complex craters located on or near the basin's rim [NASA/JPL/MIT].

Compared to the surface, the map of the interior looked extraordinarily smooth. In fact, the team found that most of the moon’s local gravity is due to surface features, such as crater rims and mountains. Except for the large impact basins, the moon’s upper crust, largely lacks dense rock structures, and is instead likely made of porous, pulverized material.

The interior map did reveal long, linear structures of denser material, which Zuber and her team believe to be buried lunar dikes — formed from magma that seeped into large fractures in the crust, and then solidified into dense walls of rock. These dikes represent evidence for expansion of the moon in its earliest history. But overall, 98 percent of the lunar crust is fragmented — a clear remnant of very early, very massive impacts.

“This is interesting for the moon,” Zuber says. “But what it also means is that every other planet was being bombarded like this.” The resulting fractures, she says, affect the way a planetary body loses heat and also provide a pathway for the transport of interior fluids.

David Kring, a senior staff scientist at the Lunar and Planetary Institute in Houston, says knowing the extent of pulverization in the moon’s crust is an essential detail needed to determine the moon’s bulk composition. Such information would go a long way toward identifying the processes the formed the moon and other planets.

“The staggering quality of the data reported by Professor Zuber and her colleagues is amazing,” says Kring, who was not involved in the research. “The data are exciting because they foretell far more insights than are captured in these initial three papers.”

NASA has scheduled a news conference to discuss the planned deorbiting and impact of the GRAIL spacecraft, December 13.

In addition to GRAIL’s discoveries, Zuber says another major accomplishment has been the performance of the spacecraft themselves. To achieve the mission’s science goals, the two probes, which can travel more than 200 kilometers apart, needed to be able to measure changes in the distance between them to within a few tenths of a micron per second. But GRAIL actually outperformed its measurement requirements by about a factor of five, resolving changes in spacecraft distance to several hundredths of a micron per second — one twenty-thousandth the velocity that a snail travels. 

“On this mission, with two spacecraft, everything had to go perfectly twice,” Zuber says, adding proudly: “Imagine you’re a parent raising a twins, and your children sit down at the piano and play a duet perfectly. That’s how it feels.”

New study answers lunar exploration concepts outlined by National Research Council in 2007

A highly resampled oblique view of the vent formation within Schrödinger basin, in the far south of the lunar far side. The basin represents a relatively new formation the excavation of which appears to have uncovered rich detail of earlier lunar morphology. LROC NAC observation M121415248LR [NASA/GSFC/Arizona State University].

A significant lunar landing site study released Monday, by the Center for Lunar Science and Exploration, addresses priorities set out in 2007 in a very influential report released by the National Research Council's Space Studies Board, The Scientific Context for the Exploration of the Moon.

Over a five year period, eight summer study groups researched our present understanding of the Moon, including voluminous new data returned by the Lunar Reconnaissance Orbiter (LRO) since 2009, and addressed central concepts outlined by the National Research Council in 2007 in a detailed report entitled A Global Lunar Landing Site Study to Provide the Scientific Context for the Exploration of the Moon.

Co-editors David A. Kring and Daniel D. Durda made their announcement online, Monday, November 26.

“The Moon is still largely unexplored. The work captured here will hopefully point mission planners to the most productive science and exploration sites on the Moon. We are ready to get back on the surface of the Moon and spark another era of discovery.

“As this study unfolded, it became clear the Apollo landing sites, while completely re-shaping our understanding of the solar system 50 years ago, represent only a tiny fraction of the lunar surface. Other sites can reveal completely new details of lunar history and are, arguably, better sites for addressing the fundamentally important issues identified in the NRC (2007) report The Scientific Context for Exploration of the Moon.

“This study asked a simple question, where on the lunar surface could the objectives in the 2007 report? Maps keyed to each of those objectives were created and, when those maps were stacked, several lunar surface locations popped out as the scientifically-richest landing sites.

Citing a few examples of highlights from the report, Kring wrote, “Schrödinger basin, on the lunar far side and within the ancient South Pole-Aitken basin, is the location where the largest range of objectives can be addressed. 

Very small scale laser altimetry (LOLA)-based topography shows the Schrödinger basin region of interest, and the Amundsen basin, in context with Shackleton crater and the lunar South Pole [NASA/LMMP].

For studies of polar volatiles, including water ice, Amundsen basin may be a better target than Shackleton crater. “But to truly resolve all of the NRC (2007) objectives,” wrote Kring, “ global access to the Moon is required.”

The report identifies a huge number of other productive landing sites across the lunar surface. "Not surprising," Kring wrote, "some favorites from the past, like Mare Orientale, appear in the report, but some surprises also emerged."

The study is available online, in Adobe Reader format at http://www.lpi.usra.edu/nlsi/CLSE-landing-site-study/

FIGURE 4.25 (Science Concept 4 Discussion) Amundsen Crater interior, showing (Permanently Shadowed Regions PSRs - dark blue), sites where all five Science Concept 4 Science Goal can be met (light blue), proposed landing sites (stars), and proposed science stations (circles). Radii of 10 and 20 km from the landing sites are shown as solid and dashed lines, respectively. Temperatures  within parts of the local PSR are never higher than 54°K - Base map is LRO/WAC/LOLA shaded relief.

The report is the product of an immense amount of work by eight student teams working through the Lunar and Planetary Research Institute and Johnson Space Center Lunar Exploration Summer Intern Program. These students had the technical skills to digest the scientific and exploration concepts, define the lunar surface requirements those concepts imply, process relevant spacecraft and sample data, and then produce maps of suitable landing sites.

Seven of the teams examined Concepts I through VII in the NRC's 2007 report.  Prompted by NASA, an eighth team took a closer look at the South Pole-Aitken basin to determine which objectives could be addressed within there. Teams did not evaluate Concept VIII in the 2007 report because it should soon addressed by the LADEE spacecraft scheduled for launch in 2013.

"The report is released with a single caveat," according to Kring. "The results represent a series of summer studies and are not intended to provide final detailed descriptions of landing sites. Still, this landing site study provides a comprehensive and global assessment of the NRC's 2007 science goals for the exploring the Moon.

"It is an excellent foundation for more detailed studies once specific missions are being planned."