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/

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."

NLSI team sheds light on 'late heavy bombardment'

Tentative 'hard' evidence of 'late heavy bombardment' and lunar cataclysm surmised by NLSI team may have resulted from a shift in the positions of the outer planets "late" in the early history of our star system's formation, throwing smaller rocky airless bodies into new trajectories and raining into the inner solar system. Post-Lunar Cataclysm diagram of the Solar System [LPI/Marchi/Bottke/Kring/Morbidelli].

A team of NLSI researchers have discovered that debris that caused a "lunar cataclysm" on the Moon 4 billion years ago struck it at much higher speeds than those that made the most ancient craters. The scientists found evidence supporting this scenario by examining the history of crater formation on the Moon.

During Earth's earliest days, our planet and others in the inner solar system, including the Moon, experienced repeated impacts from debris that formed the building blocks of the planets. Over time, as material was swept up and incorporated into the inner planets, the rate of impacts decreased. Then, roughly 4 billion years ago, a second wave of impacts appears to have taken place, with lunar projectiles hitting at much higher speeds. This increase could reflect the origin of the debris, where main belt asteroids were dislodged and sent into the inner solar system by shifts in the orbits of the giant planets.

The team is composed of Simone Marchi, an NLSI postdoctoral fellow, William Bottke, the NLSI Team Lead at Southwest Research Institute, Columbia, Md., David Kring, the NLSI Team Lead at USRA's Lunar and Planetary Institute in Houston, and Alessandro Morbidelli from the Observatoire de la Cote d’Azur, France. Their research paper, “On the Onset of the Lunar Cataclysm as Recorded in its Ancient Crater Populations,” was recently published in the journal Earth and Planetary Science Letters.

Nectaris basin, surrounding impacts of the same age and
size may have formed from progenitors traveling at a
higher velocity than elsewhere [NASA/LMMP].

The scientists analyzed digital maps of the lunar surface to learn about its history. Their analysis shows that craters formed near the 860 km diameter Nectaris impact basin were created by projectiles hitting twice as fast as those found on more ancient terrains. This was represented by a subtle shift in crater sizes, with the crater themselves thirty to forty percent larger on average than those found in comparable populations with older craters. The scientists believe this can be best explained by an increase in the velocities of the projectiles that produced the younger craters.

The increase in velocities may indicate a change in the solar system when the craters were created. The analysis supports the "lunar cataclysm" hypothesis that the brief pulse of impacting objects 4 billion years ago was due to gravitational disturbances caused by the reorganization of the giant planets as their orbits changed. Nectaris, a crater close to the Apollo 16 landing site, appears to have recorded the spike in asteroid impacts during the "lunar cataclysm."

Determining the magnitude and duration of any impact cataclysm and testing that hypothesis is a top science priority for future exploration of the Moon, according to Scientific Context for the Exploration of the Moon  (2007) by the National Research Council's Space Studies Board.

When Apollo astronauts gathered rock samples from the Moon, many samples had ages dating back 3.9 to 4 billion years ago, suggesting an enhanced pulse of bombardment. If a bombardment of asteroids hit the Moon as theorized, there could be indicators left on the lunar surface that would help validate the theory. Detailed mapping by the United States Geological Survey has previously identified small regions of the lunar surface that might contain clues about the bombardment. The team re-studied those ancient surfaces and measured the sizes of the impact craters using new data obtained from the Lunar Orbiter Laser Altimeter, an instrument on NASA’s Lunar Reconnaissance Orbiter (LRO) currently orbiting around the Moon.

“This is an exciting time for lunar research with LRO and other spacecraft providing so much new data,” said lead author Simone Marchi. “Collaborating with scientists of different disciplines allowed us to link these observational data to dynamical models to put new constraints on solar system history.”

The inferred increase in velocity seems to have occurred after the Moon’s largest impact basin was produced, the 2,500-kilometer-diameter South Pole-Aitken Basin, but before the formation of the largest lava-filled impact basins on the lunar nearside, visible from backyards around the world.

“It is fascinating that the surface of our own Moon records evidence of orbital changes in Jupiter and Saturn that took place so long ago,” said NLSI Director Yvonne Pendleton.

The onset of the lunar cataclysm as recorded in its ancient crater populations
Earth and Planetary Science Letters, Volumes 325–326, 1 April 2012, Pages 27-38
Simone Marchi, William F. Bottke, David A. Kring, Alessandro Morbidelli

View Abstract 

Scientists Detect Dramatic Shift in the Energy of Impacting
Asteroids that Pummeled the Ancient Earth and Moon
Dr. Simone Marchi, NLSI Postdoctoral Fellow (USRA, February 27, 2012)

Space Neighborhood needs watching

Blind Spots and Fuzzy Vision looking for Near-Earth Asteroids
Next Big Future

From New Scientist, existing sky surveys miss many asteroids smaller than 1 km across, leaving the door open to damaging impacts of Earth with little of no warning, a panel of scientists reports. Doing better will require devoting more powerful telescopes to asteroid hunting, but no one has committed the funds needed to do so, it says

NASA calculated, that to spot the asteroids as required by (Congressional mandate) would cost about $800 million between neo and 2020, either with a new ground-based telescope or a space observation system... If NASA (received) only $300 million, if could find most asteroids bigger than 1000 feet across..."

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