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NASA NTRS2011

ALH84001: The Key to Unlocking Secrets About Mars-15 Years and Counting

From the December 27, 1984 discovery of ALH84001, and its subsequent identification as a sample of Mars in 1993, mystery and debate has surrounded the meteorite [1]. With the realization that the ALH84001 sample was a orthopyroxenite and one of the oldest SNC meteorites (approx.4.09 Ga) [2] available to study, important and critical information about the Martian hydrosphere and atmosphere along with the early history and evolution of the planet could be obtained by studying the unique carbonate globules (approx.3.9 Ga) in the sample [3]. The initial work showed the carbonate globules were deposited within fractures and cracks in the host-orthopyroxene by low-temperature aqueous fluids [4]. Ideas that the carbonates were formed at temperatures [5] approaching 800 C were ruled out by later experiments [6]. The 1996 announcement by McKay et al. [7] that ALH84001 contained features which could be interpreted as having a biogenic origin generated considerable excitement and criticism. The NASA Administrator Dan Golden said the 1996 ALH84001 announcement saved NASAs Mars planetary exploration program and injected $6 billion dollars over five years into the scientific research and analysis efforts [8]. All of the original four lines of evidence for possible biogenic features within ALH84001 offered by McKay et al. have withstood the test of time. Criticism has been directed at the interpretation of the 1996 analytical data. Research has expanded to other SNC meteorites. Despite the numerous attacks on the ideas, the debate continues after 15 years. The 2009 paper by Thomas-Keprta et al. [9] on the origins of a suite of magnetites within the ALH84001 has offered strong arguments that some of the magnetites can only be formed by biogenic processes and not from thermal decomposition or shock events which happened to the meteorite. NASA s Astrobiology Institute was formed from the foundation laid by the ALH84001 hypothesis of finding life beyond the Earth. The strong astrobiology outreach programs have expanded because of the work done on the Martian meteorites. De-spite the criticism on the biogenic-like features in ALH84001, the meteorite has opened a window into the early history of Mars. Clearly low-temperature fluids have left their signatures within the ALH84001 meteorite and subsequent cratering events on Mars have been recorded on observable features within the meteorite. The 15 years of detailed study on ALH84001 and its unique carbonate globules have clearly shown formational and secondary processes at work on Mars. Now we need a well-documented Mars sample return mission.

Gibson, Everett K.↗

NASA NTRS2006

Dynamic Features in and nearby a Prominence

We will discuss the thermal and dynamic properties of dynamic structures in and around a prominence channel observed on the limb on 17 April 2003. Observations were taken with the Solar and Heliospheric Observatory's Solar Ultraviolet Measurements of Emitted Radiation (SOHO/SUMER) in lines formed at temperatures from 80,000 to 1.6 million K. The instrument was pointed to a single location and took a series of 90 s exposures. Two-dimensional context was provided by the Transition Region and Coronal Explorer (TRACE) in the UV and EUV and by the Kanzelhohe Solar Observatory in H-alpha. Two dynamic features were studied in depth: a prominence activation and repeated motions in a loop nearby the prominence. We were able to calculate three-dimensional geometries and trajectories, differential emission measure, and limits on the average density, kinetic and thermal energies. These observations provide important tests for models of dynamics in prominences and cool (approx.10(exp 5) K) loops.

Kucera, T.↗

NASA NTRS1999

Electric organ discharges and electric images during electrolocation

Weakly electric fish use active electrolocation - the generation and detection of electric currents - to explore their surroundings. Although electrosensory systems include some of the most extensively understood circuits in the vertebrate central nervous system, relatively little is known quantitatively about how fish electrolocate objects. We believe a prerequisite to understanding electrolocation and its underlying neural substrates is to quantify and visualize the peripheral electrosensory information measured by the electroreceptors. We have therefore focused on reconstructing both the electric organ discharges (EODs) and the electric images resulting from nearby objects and the fish's exploratory behaviors. Here, we review results from a combination of techniques, including field measurements, numerical and semi-analytical simulations, and video imaging of behaviors. EOD maps are presented and interpreted for six gymnotiform species. They reveal diverse electric field patterns that have significant implications for both the electrosensory and electromotor systems. Our simulations generated predictions of the electric images from nearby objects as well as sequences of electric images during exploratory behaviors. These methods are leading to the identification of image features and computational algorithms that could reliably encode electrosensory information and may help guide electrophysiological experiments exploring the neural basis of electrolocation.

Review, Tutorial↗

NASA NTRS1992

Lunar and planetary landers for human exploration missions

This paper describes characteristics of lunar and planetary landers and mission profiles. Requirements are discussed, and propulsion and aerodynamic features are described. The paper covers recent history of concepts, configuration design drivers, propulsion, aerodynamics and aeroheating as applicable, structural and launch packaging factors, a summary of mission profiles, a description of the evolution of concepts, and reasons why the evolution has gone as it has.

Woodcock, Gordon↗

NASA NTRSDate not supplied

Tomography Analysis of Orion Artemis 1 Heatshield Sample

The Orion spacecraft, under NASA's Artemis program, is an integral step in humanity's ambitions of deep space exploration, including our return to the Moon and subsequent mission to Mars. The performance of Orion's heatshield is central to ensuring the safety and success of such missions. This presentation offers a comprehensive overview of the process used in and findings derived from tomography scans of an Artemis 1 heatshield sample executed at the Lawrence Berkeley National Laboratory's Advanced Light Source. These tomography scans captured high-resolution X-Ray images of the heatshield's microstructure, allowing advanced imaging to be employed for 3D image segmentation and visualization of the sample. The Porous Media Analysis (PuMA) software stands central to our analysis, offering robust computational algorithms and methodologies to digitally compute properties of the heatshield material. The presentation discusses the following derived metrics: - Volume fractions, representing the spatial distribution and amounts of various components throughout the heatshield’s depth. - Porosity and crack distributions, offering insights into the void space within the material, critical for understanding the heatshield's structural integrity. - Fiber orientation, detailing the alignment and arrangement of fibers, significant for material orthotropy. - Permeability estimates, quantifying the passage of gas through the material, relevant for re-entry conditions and pyrolysis gasses. One distinctive feature of this study is the comparative evaluation against data obtained from tomography scans of the Exploration Flight Test-1 (EFT-1) heatshield. Such a comparison offers multiple insights, including evaluation of the consistency and repeatability of manufacturing processes as well as understanding of any evolutionary changes in heatshield design or material properties.

Micro-tomography↗

NASA NTRS1979

NASA's search for the solar connection. II

A survey of future space missions planned to investigate the sun and how its events affect the earth is presented. The International Solar-Polar mission, scheduled for 1983, is designed to investigate the three-dimensional structure of the solar-wind flow and to study the corona from above the sun's poles. The Spacelab mission will make major contributions to solar study by employing a 1.25 m telescope for observations from the near violet to the near infrared wavelengths with an angular resolution of 0.1 arc sec, and will be capable of resolving features on the sun 72 km across. Other missions, including the International Sun-Earth Explorer and the solar cycle and dynamic mission, which is designed to study the global oscillations of the sun, are also discussed.

Chapman, R. W.↗

NASA NTRS1985

The problem of scale in planetary geomorphology

Recent planetary exploration has shown that specific landforms exhibit a significant range in size between planets. Similar features on Earth and Mars offer some of the best examples of this scale difference. The difference in heights of volcanic features between the two planets has been cited often; the Martian volcano Olympus Mons stands approximately 26 km high, but Mauna Loa rises only 11 km above the Pacific Ocean floor. Polygonally fractured ground in the northern plains of Mars has diameters up to 20 km across; the largest terrestrial polygons are only 500 m in diameter. Mars also has landslides, aeolian features, and apparent rift valleys larger than any known on Earth. No single factor can explain the variations in landform size between planets. Controls on variation on Earth, related to climate, lithology, or elevation, have seldom been considered in detail. The size differences between features on Earth and other planets seem to be caused by a complex group of interacting relationships. The major planetary parameters that may affect landform size are discussed.

Rossbacher, L. A.↗

NASA NTRS1984

Recent developments in lithologic mapping using remote sensing data

Major development trends noted in remote sensing scanners are toward greater spatial and spectral resolution, as well as the acquisition of data over a broader portion of the electromagnetic spectrum. Attention is presently given to representative samples of the product of two new-generation satellite sensors, the Landsat-4 Thematic Mapper and SPOT, as well as the status of airborne scanner research aimed at the exploration of multispectral data in the thermal IR wavelength region (which encompasses the diagnostic spectral features of silicates and carbonates). Testing is underway for scanners having spectral bands as narrow as 0.01 micron in the visible and near-IR, which will be capable of identifying specific minerals.

Abrams, M.↗

NASA NTRS1994

Mission Operations Centers (MOCs): Integrating key spacecraft ground data system components

In an environment characterized by decreasing budgets, limited system development time, and user needs for increased capabilities, the Mission Operations Division (MOD) at the National Aeronautics and Space Administration Goddard Space Flight Center initiated a new, cost-effective concept in developing its spacecraft ground data systems: the Mission Operations Center (MOC). In the MOC approach, key components are integrated into a comprehensive and cohesive spacecraft planning, monitoring, command, and control system with a single, state-of-the-art graphical user interface. The MOD is currently implementing MOC's, which feature a common, reusable, and extendable system architecture, to support the X-Ray Timing Explorer (XTE), Tropical Rainfall Measuring Mission (TRMM), and Advanced Composition Explorer (ACE) missions. As a result of the MOC approach, mission operations are integrated, and users can, with a single system, perform real-time health and safety monitoring, real-time command and control, real-time attitude processing, real-time and predictive graphical spacecraft monitoring, trend analysis, mission planning and scheduling, command generation and management, network scheduling, guide star selection, and (using an expert system) spacecraft monitoring and fault isolation. The MOD is also implementing its test and training simulators under the new MOC management structure. This paper describes the MOC concept, the management approaches used in developing MOC systems, the technologies employed and the development process improvement initiatives applied in implementing MOC systems, and the expected benefits to both the user and the mission project in using the MOC approach.

Harbaugh, Randy↗

NASA NTRS1994

Search for CO absorption bands in IUE far-ultraviolet spectra of cool stars

Observations of the red supergiant (M2 Iab) alpha Ori with the Goddard High Resolution Spectrograph (GHRS) on board the Hubble Space Telescope (HST) have provided an unambiguous detection of a far-ultraviolet (far-UV) chromospheric continuum on which are superposed strong molecular absorption bands. The absorption bands have been identified by Carpenter et al. (1994) with the fourth-positive A-X system of CO and are likely formed in the circumstellar shell. Comparison of these GHRS data with archival International Ultraviolet Explorer (IUE) spectra of alpha Ori indicates that both the continuum and the CO absorption features can be seen with IUE, especially if multiple IUE spectra, reduced with the post-1981 IUESIPS extraction procedure (i.e., with an oversampling slit), are carefully coadded to increase the signal to noise over that obtainable with a single spectrum. We therefore initiated a program, utilizing both new and archival IUE Short Wavelength Prime (SWP) spectra, to survey 15 cool, low-gravity stars, including alpha Ori, for the presence of these two new chromospheric and circumstellar shell diagnostics. We establish positive detections of far-UV stellar continua, well above estimated IUE in-order scattered light levels, in spectra of all of the program stars. However, well-defined CO absorption features are seen only in the alpha Ori spectra, even though spectra of most of the program stars have sufficient signal to noise to allow the dectection of features of comparable magnitude to the absorptions seen in alpha Ori. Clearly if CO is present in the circumstellar environments of any of these stars, it is at much lower column densities.

Gessner, Susan E.↗

NASA NTRS1996

Cross-Cultural Barriers to Effective Communication in Aviation

Communication is essential to safe flight, as evidenced by several accidents in which crew communicates was found to have contributed to the accidents. This chapter documents the essential role of explicit efficient communication to flight safety with a global context. It addresses communication between flight crews and air traffic controllers in regions a the world where pilots and controllers speak different native languages, as well as cases in which crew members within the flight deck represent different native languages and cultures. It also addresses problems associated with "exporting" crew resource management training programs to parts of the world which values and norms differ from those of the United States, where these programs were initially developed. This chapter is organized around several central questions: (1) What are various kinds of communication failures and what are their consequences; (2) What are the causes of communication failure; (3) What are features of effective crew communication; (4) What can be done to enhance communication success? To explore a wider range of communication failures than available from accident reports, we examined a set of incident reports from the Aviation Safety Reporting System. These could be classified into three major categories: those in which language actually interfered with transmission of a message; those in which transmission was adequate but the context was not expressed unambiguously and thus the message received was not the same as the message intended; and those in which the message was received as intended, but was not adequately understood or acted upon, mainly because of cultural factors. The consequences of failed communication can be flight errors (such as when a clearance is not received correctly), loss of situation awareness, or failure of crew members (or ATC and pilots) to build a shared understanding of a situation. Causes of misunderstanding can be traced to a number of sources, often grounded in faulty assumptions held by one or both parties to a conversation. Speakers and listeners often experience "illusionary understanding" in which they think they understand each other, but in fact do not. While this problem can exist within a single culture, it is much more serious across cultures. Training in effective explicit communication is a component of Crew Resource Management training programs developed in the U.S. These programs are being adopted by airlines around the world, with varying degrees of success. The level of success in part depends on how similar the conversational and social styles of those cultures are to those of the U.S. A factor that influences conversational style is a culture's relative positioned on two major dimensions that distinguish national cultural groups: individualism vs. collectivism and degree of power distance. The chapter concludes with a discussion of techniques for overcoming the various classes of communication failures and for effectively adapting training programs to fit the values and norms of cultures around the globe.

Fischer, U.↗

NASA NTRS2005

Current results from a Rover Science Data Analysis System

In this paper, we provide a brief overview of the OASIS system, and then describe our recent successes in integrating with and using rover hardware. OASIS currently works in a closed loop fashion with onboard control software (e.g., navigation and vision) and has the ability to autonomously perform the following sequence of steps: analyze gray scale images to find rocks, extract the properties of the rocks, identify rocks of interest, retask the rover to take additional imagery of the identified target and then allow the rover to continue on its original mission. We also describe the early 2004 ground test validation of specific OASIS components on selected Mars Exploration Rover (MER) images. These components include the rockfinding algorithm, RockIT, and the rock size feature extraction code. Our team also developed the RockIT GUI, an interface that allows users to easily visualize and modify the rock-finder results. This interface has allowed us to conduct preliminary testing and validation of the rockfinder's performance.

Coupled Layer Architecture for Robotic Autonomy (C↗

NASA NTRS2006

The Location of the CO2, Fundamental in Clathrate Hydrates and its Application to Infrared Spectra of Icy Solar System Objects

CO2 is present on the surface of many Solar System objects, but not always as a segregated, pure ice. In pure CO2-ice, the fundamental absorption is located near 4.268 micron (2343.3 wavenumbers). However, on several objects, the CO2 fundamental is shifted to higher frequency. This shift may be produced by CO2 gas trapped in another material, or adsorbed onto minerals. We have seen that a mixture of H2O, CH3OH4 and CO2 forms a type II clathrate when heated to 125 K and produces a CO2 fundamental near 4.26 micron. The exact location of the feature is strongly dependent on the initial ratio of the three components. We are currently exploring various starting ratios relevant to the Solar System to determine the minimum amount of CH3OH needed to convert all of the CO2 to the clathrate, i.e. eliminate the splitting of the CO2 fundamental. We are testing the stability of the clathrate to thermal processing and UV photolysis, and documenting the changes seen in the spectra in the wavelength range from 1-5 micron. We acknowledge financial support from the Origins of Solar Systems Program, the Planetary Geology and Geophysics and the NASA Postdoctoral Program.

Sandford, S. A.↗

NASA NTRS2009

Cooperative Three-Robot System for Traversing Steep Slopes

Teamed Robots for Exploration and Science in Steep Areas (TRESSA) is a system of three autonomous mobile robots that cooperate with each other to enable scientific exploration of steep terrain (slope angles up to 90 ). Originally intended for use in exploring steep slopes on Mars that are not accessible to lone wheeled robots (Mars Exploration Rovers), TRESSA and systems like TRESSA could also be used on Earth for performing rescues on steep slopes and for exploring steep slopes that are too remote or too dangerous to be explored by humans. TRESSA is modeled on safe human climbing of steep slopes, two key features of which are teamwork and safety tethers. Two of the autonomous robots, denoted Anchorbots, remain at the top of a slope; the third robot, denoted the Cliffbot, traverses the slope. The Cliffbot drives over the cliff edge supported by tethers, which are payed out from the Anchorbots (see figure). The Anchorbots autonomously control the tension in the tethers to counter the gravitational force on the Cliffbot. The tethers are payed out and reeled in as needed, keeping the body of the Cliffbot oriented approximately parallel to the local terrain surface and preventing wheel slip by controlling the speed of descent or ascent, thereby enabling the Cliffbot to drive freely up, down, or across the slope. Due to the interactive nature of the three-robot system, the robots must be very tightly coupled. To provide for this tight coupling, the TRESSA software architecture is built on a combination of (1) the multi-robot layered behavior-coordination architecture reported in "An Architecture for Controlling Multiple Robots" (NPO-30345), NASA Tech Briefs, Vol. 28, No. 10 (October 2004), page 65, and (2) the real-time control architecture reported in "Robot Electronics Architecture" (NPO-41784), NASA Tech Briefs, Vol. 32, No. 1 (January 2008), page 28. The combination architecture makes it possible to keep the three robots synchronized and coordinated, to use data from all three robots for decision- making at each step, and to control the physical connections among the robots. In addition, TRESSA (as in prior systems that have utilized this architecture) , incorporates a capability for deterministic response to unanticipated situations from yet another architecture reported in Control Architecture for Robotic Agent Command and Sensing (NPO-43635), NASA Tech Briefs, Vol. 32, No. 10 (October 2008), page 40. Tether tension control is a major consideration in the design and operation of TRESSA. Tension is measured by force sensors connected to each tether at the Cliffbot. The direction of the tension (both azimuth and elevation) is also measured. The tension controller combines a controller to counter gravitational force and an optional velocity controller that anticipates the motion of the Cliffbot. The gravity controller estimates the slope angle from the inclination of the tethers. This angle and the weight of the Cliffbot determine the total tension needed to counteract the weight of the Cliffbot. The total needed tension is broken into components for each Anchorbot. The difference between this needed tension and the tension measured at the Cliffbot constitutes an error signal that is provided to the gravity controller. The velocity controller computes the tether speed needed to produce the desired motion of the Cliffbot. Another major consideration in the design and operation of TRESSA is detection of faults. Each robot in the TRESSA system monitors its own performance and the performance of its teammates in order to detect any system faults and prevent unsafe conditions. At startup, communication links are tested and if any robot is not communicating, the system refuses to execute any motion commands. Prior to motion, the Anchorbots attempt to set tensions in the tethers at optimal levels for counteracting the weight of the Cliffbot; if either Anchorbot fails to reach its optimal tension level within a specified time, it sends message to the other robots and the commanded motion is not executed. If any mechanical error (e.g., stalling of a motor) is detected, the affected robot sends a message triggering stoppage of the current motion. Lastly, messages are passed among the robots at each time step (10 Hz) to share sensor information during operations. If messages from any robot cease for more than an allowable time interval, the other robots detect the communication loss and initiate stoppage.

Stroupe, Ashley↗

NASA NTRS2012

Human Settlements in the South-Central U.S., Viewed at Night from the International Space Station

A recent innovation of astronauts observing Earth from the International Space Station (ISS) is documenting human footprints by photographing city lights at night time. One of the earliest night-time images from the ISS was the US-Mexico border at El Paso-Ciudad Juarez. The colors, patterns and density of city lights document the differences in the cultural settlement patterns across the border region, as well as within the urban areas themselves. City lights help outline the most populated areas in settlements around the world, and can be used to explore relative population densities, changing patterns of urban/suburban development, transportation networks, spatial relationship to geographic features, and more. The data also provides insight into parameters such as surface roughness for input into local and regional climate modeling and studies of light pollution. The ground resolution of night-time astronaut photography from the ISS is typically an order of magnitude greater than current Defense Meteorological Satellite Program (DMSP) data, and therefore can serve as a "zoom lens" for selected urban areas. Current handheld digital cameras in use on the ISS, optimized for greater light sensitivity, provide opportunities to obtain new detailed imagery of atmospheric phenomena such as airglow, aurora, and noctilucent clouds in addition to documenting urban patterns. ISS astronauts have taken advantage of increasingly sensitive digital cameras to document the world at night in unprecedented detail. In addition, the capability to obtain time-lapse imagery from fixed cameras has been exploited to produce dynamic videos of both changing surface patterns around the world and atmospheric phenomena. We will profile some spectacular images of human settlements over the South-Central U.S., and contrast with other images from around the world. More data can be viewed at http://eol.jsc.nasa.gov/Videos/CrewEarthObservationsVideos/. US-Mexico border is obvious by the different lighting pattern. Not surprisingly, the densely illuminated city of Juarez indicates a higher population; El Paso's smaller population is spread out over a larger area.

Dawson, Melissa↗

NASA NTRS2005

Vision guided landing of an an autonomous helicopter in hazardous terrain

Future robotic space missions will employ a precision soft-landing capability that will enable exploration of previously inaccessible sites that have strong scientific significance. To enable this capability, a fully autonomous onboard system that identifies and avoids hazardous features such as steep slopes and large rocks is required. Such a system will also provide greater functionality in unstructured terrain to unmanned aerial vehicles. This paper describes an algorithm for landing hazard avoidance based on images from a single moving camera. The core of the algorithm is an efficient application of structure from motion to generate a dense elevation map of the landing area. Hazards are then detected in this map and a safe landing site is selected. The algorithm has been implemented on an autonomous helicopter testbed and demonstrated four times resulting in the first autonomous landing of an unmanned helicopter in unknown and hazardous terrain.

Mars Landing↗

NASA NTRS2005

A low-volume, low-mass, low-power UHF proximity micro-transceiver for Mars Exploration

UHF half-duplex micro-transceiver measuring 1 cubic centimeter, weighing less than 10 grams, and operating at 40 mW on receive and 50mW, 300mW, or 3W on transmit is described. The micro-transceiver is being designed for future Mars exploration missions, but can be adapted for other proximity links. It supports transmission rates up to 256 ksps and higher in BPSK or QPSK format for data return and receives command/control instructions at up to 8 ksps. In addition to its low mass/power features, temperature compensated circuit and system design and radiation tolerance allow operation outside of large shielded enclosures, further reducing the mass and complexity of exploration vehicles.

Silicon-on-Sapphire (SOS)↗

NASA NTRS2014

Inferred Variable FeO Content in Medium-sized Lunar Pyroclastic Deposits from LRO Diviner Data

Lunar pyroclastic deposits (LPDs) are low albedo features that mantle underlying terrain (Gaddis et al. 1985). They are high priority targets for science and exploration as they are believed to originate from and therefore reflect the composition of the deep lunar interior (NRC, 2011). They are also the best potential resource of oxygen out of any Apollo samples (Allen et al. 1996). Historically, LPDs have been divided into regional versus local categories (Gaddis et al. 2003). The large (>1000 km2 area) regional deposits are deeply sourced (>400 km deep) and result from fire fountaining. Small (<1000 km2) local deposits are thought to result from Vulcanian eruptions in which magma is slowly emplaced beneath the surface until enough volatiles exsolve and the high pressure causes an explosion. Bennett et al. (2013) identified a local deposit (674 km2 area) that may have resulted from both Vulcanian activity and fire fountaining. This deposit potentially represents a new intermediate class of LPDs that straddles the interface between the two formation mechanisms. The deposit also exhibits the highest inferred FeO wt.% of any known lunar glass. In this work we investigate the inferred FeO abundances of other medium-sized deposits to characterize this potential new class of deposits and understand the magnitude of variations in inferred FeO among pyroclastic deposits. We use the method of Greenhagen et al. (2010) to calculate the wavelength of the Christiansen Feature (CF) from Lunar Reconnaissance Orbiter Diviner Lunar Radiometer instrument thermal-infrared observations for four medium-sized deposits. From the CF values, we estimate each deposit's FeO abundance using the method of Allen et al. (2012). The four LPDs that we examined (Oppenheimer South, Beer, Cleomedes, and J. Herschel) all have average CF values from 8.22-8.28 microns, corresponding to FeO abundances of approx. 10-15 wt.%. All of these values are within the range and uncertainties of FeO abundances measured in Apollo samples. As previously identified, the Oppenheimer South deposit exhibits an area of enhanced CF values (8.49 microns) that, if the methods of Allen et al. (2012) can be extrapolated, correspond to a highest observed approx. 30 wt.% FeO. Moon Mineralogy Mapper near-infrared spectra indicate that this area is glass-rich as opposed to olivine-rich. While we are still investigating the nature of the high CF wavelength in Oppenheimer South, spatially-resolved observations there and (to a smaller degree) in our other study sites, shows that FeO wt.% can vary within LPDs. Thus, obtaining only the average FeO abundance over a large area may not be adequate to understand global variation. The magnitude of Oppenheimer South's CF variability, if due to actual surface variations rather than calibration artifacts or spectral mixing, could indicate that it is a unique deposit and not part of a new mid-sized class of deposits. The higher value could be a result of its location within the South Pole Aitken Basin and exsolution of more deeply sourced magma due to the thin crust there.

Bennett, K. A.↗