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All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Extensional tectonics during the igneous emplacement of the mafic-ultramafic rocks of the Barberton greenstone belt

The simatic rocks (Onverwacht Group) of the Barberton greenstone belt are part of the Jamestown ophiolite complex. This ophiolite, together with its thick sedimentary cover occupies a complex thrust belt. Field studies have identified two types of early faults which are entirely confined to the simatic rocks and are deformed by the later thrusts and associated folds. The first type of fault (F1a) is regional and always occurs in the simatic rocks along and parallel to the lower contacts of the ophiolite-related cherts (Middle Marker and equivalent layers). These fault zones have previously been referred to both as flaser-banded gneisses and as weathering horizons. In general the zones range between 1-30m in thickness. Displacements along these zones are difficult to estimate, but may be in the order of 1-100 km. The structures indicate that the faults formed close to horizontal, during extensional shear and were therefore low angle normal faults. F1a zones overlap in age with the formation of the ophiolite complex. The second type of faults (F1b) are vertical brittle-ductile shear zones, which crosscut the complex at variable angles and cannot always be traced from plutonic to overlying extrusive (pillowed) simatic rocks. F1b zones are also apparently of penecontemporaneous origin with the intrusive-extrusive igneous processs. F1b zones may either represent transform fault-type activity or represent root zones (steepened extensions) of F1a zones. Both fault types indicate extensive deformation in the rocks of the greenstone belt prior to compressional overthrust tectonics.

Dewit, M. J.↗
NASA NTRS1987

Thin and thick-skinned deformation in the Tharsis Region of Mars

The ridge system of the Tharsis Plateau is a dominant structural form equaled only by the radial fracture system. The structural interpretation of the ridges are: (1) folds formed by regional or local compressional stress; (2) the surface manifestation of reverse or thrust faults; or (3) folds with thrust faulting developing as a result of fold geometry. It has been suggested that the compressional events that generated the ridges occurred after the emplacement of the ridged plains volcanic units, but before the episode of faulting that generated the majority of the observed ridge-fault crosscutting relationships on the ridged plains and that it did not continue beyond the emplacement of the Syria Planum Formation or the basal units of the Tharsis Montes Formation. Models for the origin of the regional stresses involving a combination of isostatic uplift and flexural loading were proposed.

Watters, Thomas R.↗
NASA NTRS1987

The Jamestown Ophiolite Complex, Barberton mountain belt - A section through 3.5 Ga oceanic crust

The Jamestown Ophiolite Complex of the Barberton greenstone belt, South Africa, is investigated, and the intrusive nature of mafic-ultramafic units from the Komati and Kromberg formations into overlying pillow lavas and sediments is documented. Evidence is presented for multiple intrusive events within the igneous sections, including crosscutting intrusives, multiple injection of magma in the Komati section, and sheeted intrusions in the Kromberg section. The thinness of the Jamestown complex suggests that, locally at least, the ca 3.5 Ga oceanic crust was also thin, consistent with the regionally extensive metasomatic alteration.

De Wit, Maarten J.↗
NASA NTRS1990

Faults and ridges - Historical development in Tempe Terra and Ulysses Patera regions of Mars

Tempe Terra and the area north of Ulysses Patera are selected to demonstrate the various stages of faulting and ridge development in local areas. This work is accomplished by using Viking photomosaics to determine crosscutting relations of structures as well as their morphology and trend orientations. Results show that from the Early Noachian through the Early Amazonian Epochs, at least eight episodes of faulting occurred at Tempe Terra and six at Ulysses Patera. Tectonic activity at Tempe Terra was expressed mainly by densely spaced faults along the northeast extension of the Tharsis rise; faulting culminated in the Middle and Late Noachian and was superseded by transverse fault systems from the Alba Patera region during the Hesperian. Ridge formation, however, was most active in the Early Hesperian. At Ulysses Patera, an early history of tectonism is recorded by complex arrays of faults in a relatively small area of Noachian rocks.

Scott, D. H.↗
NASA NTRS1992

Magellan observations of Alpha Regio - Implications for formation of complex ridged terrains on Venus

The deformational features that make up the complex ridged terrain (CRT) of Alpha Regio are characterized, and observations of these features and their interpretations are used to evaluate quantitative models for the formation of Alpha Regio. In particular, two models are considered: a hotspot or mantle plume model and a coldspot or mantle downwelling model. Based on an analysis of the observed morphology of structures, their distribution, superposition and crosscutting relationships, and Magellan altimetry, a sequence of deformational events is suggested, and the observed topography, tectonics, and volcanism are compared with the predictions of the hotspot and coldspot models. It is found that a number of observations are more consistent with the downwelling than a hotspot model. This is particularly true of margin-parallel compressional features near the plains-CRT boundary in much of Alpha Regio.

Bindschadler, Duane L.↗
NASA NTRS1993

Seismic-triggering history of the catastrophic outflows in the Chryse region of Mars

Much attention was recently focused on the Chryse outflow channels as the source for an ocean or large lakes in the northern plains of Mars. A critical question is whether the channels formed quickly and in concert or sporadically. Crosscutting relations demonstrate multiple episodes of channel formation for some of the channels; however, for most channels, the absence of high precision in the densities of superposed impact craters prevents precise reconstruction of the duration and sequence of channeling history. Another approach to addressing the groundwater discharge history is to evaluate the hypothetical storage of the Chryse aquifer system and its recharge and triggering histories. How outflow breakouts may have been triggered by relatively frequent, large marsquakes caused by faulting and impact is discussed.

Clifford, S. M.↗
NASA NTRS1993

Photogeological analysis of Europan tectonic features

Preliminary photogeological analyses of the Pelorus Linea and Sidon Flexus regions of Europa were conducted to explore the proposal by Schenk that lateral motion of crustal blocks has occurred in a 'rift zone' including possible strike-slip, tension fracturing, and geometric plate rotation about an Euler pole. These analyses revealed features interpreted as tensional structures and block rotation in a strike-slip regime consistent with the Schenk hypotheses and implied the presence of at least two stages of crustal deformation consistent with a chronology developed by Lucchitta. Confirmation of regional scale Euler pole rotation was ambiguous, however. Up to 80 kilometers of possible extension was identified in the rift zone; to accommodate this, 'cryosubduction' is speculatively proposed as a mechanism for recycling Europan 'ice lithosphere'. The cumulative width of wedge-shaped bands included in the rift zone was measured and plotted versus distance from the inferred rotation pole. Three sharp decreases in the total width were noted. These occur roughly where certain triple bands cross the rift zone suggesting that the bands are structural features that predate and influence the zone. While the curve hints at one or more sinusoidal relationships consistent with rotation geometry, given the low photographic resolution and the preliminary nature of this examination the question of whether the observations represent coherent regional rotation modified by crosscutting structures or instead imply independent local rotations separated by these structures is unanswered by this analysis.

Tufts, B. R.↗
NASA NTRS1993

Arcuate and circular structures in the Tharsis region: Evidence of coronae on Mars

Arcuate and circular structures are evident in the Tharsis region of Mars. They involve concentric graben and fracture systems and are often associated with volcanic centers. The most prominent example is Alba Patera, a low relief volcanotectonic center. It is surrounded by a graben system comprised of the Alba and Tantalus Fossae and part of the Ceranius Fossae system that are thought to have formed during the Early Amazonian. The graben concentric to Alba Patera form an annulus that is 600 km in diameter. The similarity between Alba Patera and coronae on Venus was observed prior to the Magellan mission. Magellan imagery of Venusian coronae has revealed a number of striking similarities between these structures, Alba Patera, and the other circular structures on Mars. Coronae on Venus are circular to ovoidal volcanotectonic features that range in diameter from 60 to over 1000 km. Concentric graben form partial to complete tectonic annuli. More regionally extensive graben systems are deflected toward, and in many cases merge with, the concentric graben. Volcanic flows and domes dominate the surface enclosed within the concentric graben. However, distinctive differences exist between coronae on Venus and the structures on Mars. Circular structures on Mars lack radial graben crosscut by concentric graben. There is also no evidence of the complex topography associated with coronae on Venus. The differences between coronae on Venus and the suspected coronae on Mars may be largely due to the difference in the thickness of the elastic lithosphere on the two planets. The topographic expression of the interaction between the diapir and the lithosphere would be expected to be greatly subdued on Mars because of the large difference in lithospheric thickness. The lack of circular structures with diameters below 200 km suggests a lower limit to the size that coronae could form on Mars.

Watters, T. R.↗
NASA NTRS1992

An IDL-based analysis package for COBE and other skycube-formatted astronomical data

UIMAGE is a data analysis package written in IDL for the Cosmic Background Explorer (COBE) project. COBE has extraordinarily stringent accuracy requirements: 1 percent mid-infrared absolute photometry, 0.01 percent submillimeter absolute spectrometry, and 0.0001 percent submillimeter relative photometry. Thus, many of the transformations and image enhancements common to analysis of large data sets must be done with special care. UIMAGE is unusual in this sense in that it performs as many of its operations as possible on the data in its native format and projection, which in the case of COBE is the quadrilateralized sphereical cube ('skycube'). That is, after reprojecting the data, e.g., onto an Aitoff map, the user who performs an operation such as taking a crosscut or extracting data from a pixel is transparently acting upon the skycube data from which the projection was made, thereby preserving the accuracy of the result. Current plans call for formatting external data bases such as CO maps into the skycube format with a high-accuracy transformation, thereby allowing Guest Investigators to use UIMAGE for direct comparison of the COBE maps with those at other wavelengths from other instruments. It is completely menu-driven so that its use requires no knowledge of IDL. Its functionality includes I/O from the COBE archives, FITS files, and IDL save sets as well as standard analysis operations such as smoothing, reprojection, zooming, statistics of areas, spectral analysis, etc. One of UIMAGE's more advanced and attractive features is its terminal independence. Most of the operations (e.g., menu-item selection or pixel selection) that are driven by the mouse on an X-windows terminal are also available using arrow keys and keyboard entry (e.g., pixel coordinates) on VT200 and Tektronix-class terminals. Even limited grey scales of images are available this way. Obviously, image processing is very limited on this type of terminal, but it is nonetheless surprising how much analysis can be done on that medium. Such flexibility has the virtue of expanding the user community to those who must work remotely on non-image terminals, e.g., via modem.

Ewing, J. A.↗
NASA NTRS1994

Intelligent robotics can boost America's economic growth

A case is made for strategic investment in intelligent robotics as a part of the solution to the problem of improved global competitiveness for U.S. manufacturing, a critical industrial sector. Similar cases are made for strategic investments in intelligent robotics for field applications, construction, and service industries such as health care. The scope of the country's problems and needs is beyond the capability of the private sector alone, government alone, or academia alone to solve independently of the others. National cooperative programs in intelligent robotics are needed with the private sector supplying leadership direction and aerospace and non-aerospace industries conducting the development. Some necessary elements of such programs are outlined. The National Aeronautics and Space Administration (NASA) and the Lyndon B. Johnson Space Center (JSC) can be key players in such national cooperative programs in intelligent robotics for several reasons: (1) human space exploration missions require supervised intelligent robotics as enabling tools and, hence must develop supervised intelligent robotic systems; (2) intelligent robotic technology is being developed for space applications at JSC (but has a strong crosscutting or generic flavor) that is advancing the state of the art and is producing both skilled personnel and adaptable developmental infrastructure such as integrated testbeds; and (3) a NASA JSC Technology Investment Program in Robotics has been proposed based on commercial partnerships and collaborations for precompetitive, dual-use developments.

Erickson, Jon D.↗
NASA NTRS1993

Plains tectonism on Venus: The deformation belts of Lavinia Planitia

High-resolution radar images from the Magellan spacecraft have revealed the first details of the morphology of the Lavinia Planitia region of Venus. A number of geologic units can be distinguished, including volcanic plains units with a range of ages. Transecting these plains over much of the Lavinia region are two types of generally orthogonal features that we interpret to be compressional wrinkle ridges and extensional grooves. The dominant tectonic features of Lavinia are broad elevated belts of intense deformation that transect the plains with complex geometry. They are many tens to a few hundred kilometers wide, as much as 1000 km long, and elevated hundreds of meters above the surrounding plains. Two classes of deformation belts are seen in the Lavinia region. 'Ridge belts' are composed of parallel ridges, each a few hundred meters in elevation, that we interpret to be folds. Typical fold spacings are 5-10 km. 'Fracture belts' are dominated instead by intense faulting, with faults in some instances paired to form narrow grabens. There is also some evidence for modest amounts of horizontal shear distributed across both ridge and fracture belts. Crosscutting relationships among the belts show there to be a range in belt ages. In western Lavinia, in particular, many ridge and fracture belts appear to bear a relationship to the much smaller wrinkle ridges and grooves on the surrounding plains: ridge morphology tends to dominate belts that lie more nearly parallel to local plains wrinkle ridges, and fracture morphology tends to dominate belts that lie more nearly parallel to local plains grooves. We use simple models to explore the formation of ridge and fracture belts. We show that convective motions in the mantle can couple to the crust to cause horizontal stresses of a magnitude sufficient to induce the formation of deformation belts like those observed in Lavinia. We also use the small-scale wavelengths of deformation observed within individual ridge belts to place an approximate lower limit on the venusian thermal gradient in the Lavinia region at the time of deformation.

Squyres, Steven W.↗
NASA NTRS1998

Issues in NASA Program and Project Management. Special Edition: A Collection of Papers on NASA Procedures and Guidance 7120.5A

A key aspect of NASA's new Strategic Management System is improving the way we plan, approve, execute and evaluate our programs and projects. To this end, NASA has developed the NASA Program and Project Management processes and Requirements-NASA Procedures and Guidelines (NPG) 7120.5A, which formally documents the "Provide Aerospace Products and Capabilities" crosscutting process, and defines the processes and requirements that are responsive to the Program/Project Management-NPD 7120.4A. The Program/Project Management-NPD 7120.4A, issued November 14, 1996, provides the policy for managing programs and projects in a new way that is aligned with the new NASA environment. An Agencywide team has spent thousands of hours developing the NASA Program and Project Management Processes and Requirements-NPG 7120.5A. We have created significant flexibility, authority and discretion for the program and project managers to exercise and carry out their duties, and have delegated the responsibility and the accountability for their programs and projects.

Edward J. Hoffman↗
NASA NTRS1999

Reinventing The Design Process: Teams and Models

The future of space mission designing will be dramatically different from the past. Formerly, performance-driven paradigms emphasized data return with cost and schedule being secondary issues. Now and in the future, costs are capped and schedules fixed-these two variables must be treated as independent in the design process. Accordingly, JPL has redesigned its design process. At the conceptual level, design times have been reduced by properly defining the required design depth, improving the linkages between tools, and managing team dynamics. In implementation-phase design, system requirements will be held in crosscutting models, linked to subsystem design tools through a central database that captures the design and supplies needed configuration management and control. Mission goals will then be captured in timelining software that drives the models, testing their capability to execute the goals. Metrics are used to measure and control both processes and to ensure that design parameters converge through the design process within schedule constraints. This methodology manages margins controlled by acceptable risk levels. Thus, teams can evolve risk tolerance (and cost) as they would any engineering parameter. This new approach allows more design freedom for a longer time, which tends to encourage revolutionary and unexpected improvements in design.

Wall, Stephen D.↗
NASA NTRS2001

Improving the Capture and Re-Use of Data with Wearable Computers

At the Goddard Space Flight Center, members of the Real-Time Software Engineering Branch are developing a wearable, wireless, voice-activated computer for use in a wide range of crosscutting space applications that would benefit from having instant Internet, network, and computer access with complete mobility and hands-free operations. These applications can be applied across many fields and disciplines including spacecraft fabrication, integration and testing (including environmental testing), and astronaut on-orbit control and monitoring of experiments with ground based experimenters. To satisfy the needs of NASA customers, this wearable computer needs to be connected to a wireless network, to transmit and receive real-time video over the network, and to receive updated documents via the Internet or NASA servers. The voice-activated computer, with a unique vocabulary, will allow the users to access documentation in a hands free environment and interact in real-time with remote users. We will discuss wearable computer development, hardware and software issues, wireless network limitations, video/audio solutions and difficulties in language development.

Pfarr, Barbara↗
NASA NTRS2001

Microgravity Materials Science Conference 2000

This is Volume 1 of 3 of the 2000 Microgravity Material Science Conference that was held June 6-8 at the Von Braun Center, Huntsville, Alabama. It was organized by the Microgravity Materials Science Discipline Working Group, sponsored by the Microgravity Research Division (MRD) at NASA Headquarters, and hosted by NASA Marshall Space Flight Center and the Alliance for Microgravity Materials Science and Applications (AMMSA). It was the fourth NASA conference of this type in the microgravity materials science discipline. The microgravity science program sponsored approx. 200 investigators, all of whom made oral or poster presentations at this conference. In addition, posters and exhibits covering NASA microgravity facilities, advanced technology development projects sponsored by the NASA Microgravity Research Division at NASA Headquarters, and commercial interests were exhibited. The purpose of the conference was to inform the materials science community of research opportunities in reduced gravity and to highlight the Spring 2001 release of the NASA Research Announcement (NRA) to solicit proposals for future investigations. It also served to review the current research and activities in materials science, to discuss the envisioned long-term goals. and to highlight new crosscutting research areas of particular interest to MRD. The conference was aimed at materials science researchers from academia, industry, and government. A workshop on in situ resource utilization (ISRU) was held in conjunction with the conference with the goal of evaluating and prioritizing processing issues in Lunar and Martian type environments. The workshop participation included invited speakers and investigators currently funded in the material science program under the Human Exploration and Development of Space (HEDS) initiative. The conference featured a plenary session every day with an invited speaker that was followed by three parallel breakout sessions in subdisciplines. Attendance was close to 350 people. Posters were available for viewing during the conference and a dedicated poster session was held on the second day. Nanotechnology radiation shielding materials, Space Station science opportunities, biomaterials research, and outreach and educational aspects of the program were featured in the plenary talks. This volume, the first to be released on CD-ROM for materials science, is comprised of the research reports submitted by the Principal Investigators at the conference.

Ramachandran, Narayanan↗
NASA NTRS2001

Microgravity Materials Science Conference 2000

This is Volume 2 of 3 of the 2000 Microgravity Materials Science Conference that was held June 6-8 at the Von Braun Center, Huntsville, Alabama. It was organized by the Microgravity Materials Science Discipline Working Group, sponsored by the Microgravity Research Division (MRD) at NASA Headquarters, and hosted by NASA Marshall Space Flight Center and the Alliance for Microgravity Materials Science and Applications (AMMSA). It was the fourth NASA conference of this type in the Microgravity materials science discipline. The microgravity science program sponsored approx. 200 investigators, all of whom made oral or poster presentations at this conference- In addition, posters and exhibits covering NASA microgravity facilities, advanced technology development projects sponsored by the NASA Microgravity Research Division at NASA Headquarters, and commercial interests were exhibited. The purpose of the conference %%,its to inform the materials science community of research opportunities in reduced gravity and to highlight the Spring 2001 release of the NASA Research Announcement (NRA) to solicit proposals for future investigations. It also served to review the current research and activities in material,, science, to discuss the envisioned long-term goals. and to highlight new crosscutting research areas of particular interest to MRD. The conference was aimed at materials science researchers from academia, industry, and government. A workshop on in situ resource utilization (ISRU) was held in conjunction with the conference with the goal of evaluating and prioritizing processing issues in Lunar and Martian type environments. The workshop participation included invited speakers and investigators currently funded in the material science program under the Human Exploration and Development of Space (HEDS) initiative. The conference featured a plenary session every day with an invited speaker that was followed by three parallel breakout sessions in subdisciplines. Attendance was close to 350 people, Posters were available for viewing during the conference and a dedicated poster session was held on the second day. Nanotechnology, radiation shielding materials, Space Station science opportunities, biomaterials research, and outreach and educational aspects of the program were featured in the plenary talks. This volume, the first to be released on CD-ROM for materials science, is comprised of the research reports submitted by the Principal Investigators at the conference.

Ramachandran, Narayanan↗
NASA NTRS2001

Microgravity Materials Science Conference 2000

This is Volume 3 of 3 of the 2000 Microgravity Materials Science Conference that was held June 6-8 at the Von Braun Center, Huntsville, Alabama. It was organized by the Microgravity Materials Science Discipline Working Group, sponsored by the Microgravity Research Division (MRD) at NASA Headquarters, and hosted by NASA Marshall Space Flight Center and the Alliance for Microgravity Materials Science and Applications (AMMSA). It was the fourth NASA conference of this type in the Microgravity materials science discipline. The microgravity science program sponsored ~200 investigators, all of whom made oral or poster presentations at this conference- In addition, posters and exhibits covering NASA microgravity facilities, advanced technology development projects sponsored by the NASA Microgravity Research Division at NASA Headquarters, and commercial interests were exhibited. The purpose of the conference was to inform the materials science community of research opportunities in reduced gravity and to highlight the Spring 2001 release of the NASA Research Announcement (NRA) to solicit proposals for future investigations. It also served to review the current research and activities in material,, science, to discuss the envisioned long-term goals. and to highlight new crosscutting research areas of particular interest to MRD. The conference was aimed at materials science researchers from academia, industry, and government. A workshop on in situ resource utilization (ISRU) was held in conjunction with the conference with the goal of evaluating and prioritizing processing issues in Lunar and Martian type environments. The workshop participation included invited speakers and investigators currently funded in the material science program under the Human Exploration and Development of Space (HEDS) initiative. The conference featured a plenary session every day with an invited speaker that was followed by three parallel breakout sessions in subdisciplines. Attendance was close to 350 people, Posters were available for viewing during the conference and a dedicated poster session was held on the second day. Nanotechnology, radiation shielding materials, Space Station science opportunities, biomaterials research, and outreach and educational aspects of the program were featured in the plenary talks. This volume, the first to be released on CD-ROM for materials science, is comprised of the research reports submitted by the Principal Investigators at the conference.

Ramachandran, Narayanan↗
NASA NTRS2001

High-Purity Aluminum Magnet Technology for Advanced Space Transportation Systems

Basic research on advanced plasma-based propulsion systems is routinely focused on plasmadynamics, performance, and efficiency aspects while relegating the development of critical enabling technologies, such as flight-weight magnets, to follow-on development work. Unfortunately, the low technology readiness levels (TRLs) associated with critical enabling technologies tend to be perceived as an indicator of high technical risk, and this, in turn, hampers the acceptance of advanced system architectures for flight development. Consequently, there is growing recognition that applied research on the critical enabling technologies needs to be conducted hand in hand with basic research activities. The development of flight-weight magnet technology, for example, is one area of applied research having broad crosscutting applications to a number of advanced propulsion system architectures. Therefore, NASA Marshall Space Flight Center, Louisiana State University (LSU), and the National High Magnetic Field Laboratory (NHMFL) have initiated an applied research project aimed at advancing the TRL of flight-weight magnets. This Technical Publication reports on the group's initial effort to demonstrate the feasibility of cryogenic high-purity aluminum magnet technology and describes the design, construction, and testing of a 6-in-diameter by 12-in-long aluminum solenoid magnet. The coil was constructed in the machine shop of the Department of Physics and Astronomy at LSU and testing was conducted in NHMFL facilities at Florida State University and at Los Alamos National Laboratory. The solenoid magnet was first wound, reinforced, potted in high thermal conductivity epoxy, and bench tested in the LSU laboratories. A cryogenic container for operation at 77 K was also constructed and mated to the solenoid. The coil was then taken to NHMFL facilities in Tallahassee, FL. where its magnetoresistance was measured in a 77 K environment under steady magnetic fields as high as 10 T. In addition, the temperature dependence of the coil's resistance was measured from 77 to 300 K. Following this series of tests, the coil was transported to NHMFL facilities in Los Alamos, NM, and pulsed to 2 T using an existing capacitor bank pulse generator. The coil was completely successful in producing the desired field without damage to the windings.

Goodrich, R. G.↗