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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS1992

Measuring ocean coherence time with dual-baseline interferometry

Using the Jet Propulsion Laboratory (JPL) Airborne Synthetic Aperture Radar (AIRSAR) interferometer, measurements of the ocean coherence time at L and C band can be made at high spatial resolution. Fundamental to this measurement is the ability to image the ocean interferometrically at two different time-lags, or baselines. By modifying the operating procedure of the existing two antenna interferometer, a technique was developed make these measurements. L band coherence times are measured and presented.

Carande, Richard E.↗
NASA NTRS1993

Outgassing Data for Selecting Spacecraft Materials

This tenth compilation of outgassing data of materials intended for spacecraft use supersedes Reference Publication 1124, Revision 2, November 1990. The data were obtained at the Goddard Space Flight Center (GSFC), utilizing equipment developed at Stanford Research Institute (SRI) under contract to the Jet Propulsion Laboratory (JPL). SRI personnel developed an apparatus for determining the mass loss in vacuum and for collecting the outgassed products. The outgassing data have been presented in three different ways in order to facilitate material selection. In Section A, the materials are divided by category into the 18 probable uses, such as adhesives, greases, paints, potting compounds, and so forth. In Section B, all the materials contained in Section A are listed in alphabetical order by the manufacturer's identification. In Section C, the only materials listed are those having 'Total Mass Loss' (TML) and Collected Volatile Condensable Materials (CVCM) equal to or lower than a maximum 1.0 percent TML and a maximum 0.10 percent CVCM. These are grouped by use, as in Section A.

Campbell, William A., Jr.↗
NASA NTRS1993

Multimission image processing and science data visualization

The Operational Science Analysis (OSA) Functional area supports science instrument data display, analysis, visualization and photo processing in support of flight operations of planetary spacecraft managed by the Jet Propulsion Laboratory (JPL). This paper describes the data products generated by the OSA functional area, and the current computer system used to generate these data products. The objectives on a system upgrade now in process are described. The design approach to development of the new system are reviewed, including use of the Unix operating system and X-Window display standards to provide platform independence, portability, and modularity within the new system, is reviewed. The new system should provide a modular and scaleable capability supporting a variety of future missions at JPL.

Green, William B.↗
NASA NTRS1993

Resource allocation planning with international components

Dumas, Briggs, Reid and Smith (1989) describe the need for identifying mutually acceptable methodologies for developing standard agreements for the exchange of tracking time or facility use among international components. One possible starting point is the current process used at the Jet Propulsion Laboratory (JPL) in planning the use of tracking resources. While there is a significant promise of better resource utilization by international cooperative agreements, there is a serious challenge to provide convenient user participation given the separate project and network locations. Coordination among users and facility providers will require a more decentralized communication process and a wider variety of automated planning tools to help users find potential exchanges. This paper provides a framework in which international cooperation in the utilization of ground based space communication systems can be facilitated.

Burke, Gene↗
NASA NTRS1993

The Jet Propulsion Laboratory space exploration: Past, present and future

The most recent scientific results from space exploration carried out by the Jet Propulsion Laboratory (JPL) are discussed. To aid understanding of these results, a brief background of JPL's history is presented, followed by a description of the Deep Space Network, JPL's system of antennas which communicates with spacecraft. The results from the missions of Voyager 1 and Voyager 2 are described. The atmosphere, rings, satellites and magnetospheres of Jupiter, Saturn, Uranus and Neptune are discussed with particular emphasis on novelty of the discoveries and the challenges encountered in explaining them. A brief discussion of the impact of spray research upon space exploration follows. This is because most recently launched missions used liquid fueled rockets to escape Earth's gravity. A summary of future missions and the National Aeronautics and Space Administration's new policies is presented in the conclusion.

Bellan, Josette↗
NASA NTRS1992

Artificial Intelligence Research Branch future plans

This report contains information on the activities of the Artificial Intelligence Research Branch (FIA) at NASA Ames Research Center (ARC) in 1992, as well as planned work in 1993. These activities span a range from basic scientific research through engineering development to fielded NASA applications, particularly those applications that are enabled by basic research carried out in FIA. Work is conducted in-house and through collaborative partners in academia and industry. All of our work has research themes with a dual commitment to technical excellence and applicability to NASA short, medium, and long-term problems. FIA acts as the Agency's lead organization for research aspects of artificial intelligence, working closely with a second research laboratory at the Jet Propulsion Laboratory (JPL) and AI applications groups throughout all NASA centers. This report is organized along three major research themes: (1) Planning and Scheduling: deciding on a sequence of actions to achieve a set of complex goals and determining when to execute those actions and how to allocate resources to carry them out; (2) Machine Learning: techniques for forming theories about natural and man-made phenomena; and for improving the problem-solving performance of computational systems over time; and (3) Research on the acquisition, representation, and utilization of knowledge in support of diagnosis design of engineered systems and analysis of actual systems.

Stewart, Helen↗
NASA NTRS1994

An image assessment study of image acceptability of the Galileo low gain antenna mission

This paper describes a study conducted by NASA Ames Research Center (ARC) in collaboration with the Jet Propulsion Laboratory (JPL), Pasadena, California on the image acceptability of the Galileo Low Gain Antenna mission. The primary objective of the study is to determine the impact of the Integer Cosine Transform (ICT) compression algorithm on Galilean images of atmospheric bodies, moons, asteroids and Jupiter's rings. The approach involved fifteen volunteer subjects representing twelve institutions involved with the Galileo Solid State Imaging (SSI) experiment. Four different experiment specific quantization tables (q-table) and various compression stepsizes (q-factor) to achieve different compression ratios were used. It then determined the acceptability of the compressed monochromatic astronomical images as evaluated by Galileo SSI mission scientists. Fourteen different images were evaluated. Each observer viewed two versions of the same image side by side on a high resolution monitor, each was compressed using a different quantization stepsize. They were requested to select which image had the highest overall quality to support them in carrying out their visual evaluations of image content. Then they rated both images using a scale from one to five on its judged degree of usefulness. Up to four pre-selected types of images were presented with and without noise to each subject based upon results of a previously administered survey of their image preferences. Fourteen different images in seven image groups were studied. The results showed that: (1) acceptable compression ratios vary widely with the type of images; (2) noisy images detract greatly from image acceptability and acceptable compression ratios; and (3) atmospheric images of Jupiter seem to have higher compression ratios of 4 to 5 times that of some clear surface satellite images.

Chuang, S. L.↗
NASA NTRS1994

Design of the MESUR/pathfinder microrover

The use of unmanned robotic vehicles to assist in the exploration of Mars and other planets has been of interest to the National Aeronautics and Space Administration (NASA) for several decades and has been the focus of an ongoing research program at the Jet Propulsion Laboratory (JPL) for a similar period of time. As a result of these research activities, JPL is in the process of designing and building a small (7-9 kg) microrover to be flown aboard the Mars Environmental Survey Mission (MESUR)/Pathfinder spacecraft, which is tentatively to be launched to Mars in late 1997. The microrover will perform a variety of technology experiments designed to provide information critical to the design of future planetary rovers. In addition, the microrover will perform several science and lander related experiments using specialized onboard instruments. To enable the microrover to perform these experiments at selected target areas and at the same time deal with the long time delays (and limited communications bandwidth), a control/navigation approach combining the use of operator-designated waypoints and onboard behavior control has been adopted. The design of the MESUR/Pathfinder microrover and the overall manner in which it is controlled are described herein.

Stone, Henry W.↗
NASA NTRS1994

Issues in the development of a 10 MBPS K=15 Viterbi decoder

The NMSU Telemetry Center, in collaboration with the NASA Microelectronics Center (MRC) at UNM, has completed a study of the feasibility of building a constraint length 15, rate 1/2 Viterbi Decoder (or BVD) to operate at a rate of 10 Mbps. The BVD, if built, would make TDRSS more accessible to all users, small satellites in particular, by providing an additional 2 dB of link margin, relative to the use of the standard constraint length 7 decoder. The study included the following: review of the 1 Mbps BVD built by the Jet Propulsion Laboratory (JPL), currently the only BVD in existence; development of Specifications for the basic processing unit of the BVD (MRC); analytical Determination of performance of large constraint length convolutional codes; investigation of the impact of processor design on the overall system design; and two feasible packaging technologies, proposed by Cincinnati Electronics of Ohio. It was concluded that while the construction of the BVD is feasible, it will require the most advanced packaging technology currently available, and that the project would be best accomplished in an industrial facility. While the size, complexity, and power requirements of the BVD will be extreme, these will impact only the ground station. The spacecraft will incur a minor change in the encoder design, and the increased coding gain will allow a satellite to operate with a smaller antenna.

Osborne, William P.↗
NASA NTRS1993

OMP-26 - An interactive scheduling tool for the 26 meter subnetwork

Operations Mission Planner for the 26 Meter (26M) Antenna Subnetwork (OMP-26) is an interactive scheduling tool developed by the Jet Propulsion Laboratory (JPL) to assist in allocating the Deep Space Network (DSN) 26M antennas to support Earth-orbiting Spacecraft (SC). Prior to integrating OMP-26 into the 26M scheduling arena, the text-based, labor-intensive task lacked the sufficient means to support the 1992 mission support increase. Therefore, JPL developed the OMP-26 interactive scheduling tool to automate the time consuming tasks of the existing, manual scheduling process. OMP-26 has addressed the scheduling dilemma by assisting schedulers to identify and resolve conflicts more quickly through its graphical display features and constraint-checking editing capability. Although OMP-26 has reduced the scheduler's existing workload by easing the identification and resolution of conflicts, it will not meet the needs of another mission support increase to occur by 1995. Therefore, future plans for OMP-26 involve transitioning from a solely interactive scheduling tool to one that is highly automated and more powerful.

Rosas, Jody L.↗
NASA NTRS1993

A ground-based memory state tracker for satellite on-board computer memory

The TOPEX/POSEIDON satellite, currently in Earth orbit, will use radar altimetry to measure sea surface height over 90 percent of the world's ice-free oceans. In combination with a precise determination of the spacecraft orbit, the altimetry data will provide maps of ocean topography, which will be used to calculate the speed and direction of ocean currents worldwide. NASA's Jet Propulsion Laboratory (JPL) has primary responsibility for mission operations for TOPEX/POSEIDON. Software applications have been developed to automate mission operations tasks. This paper describes one of these applications, the Memory State Tracker, which allows the ground analyst to examine and track the contents of satellite on-board computer memory quickly and efficiently, in a human-readable format, without having to receive the data directly from the spacecraft. This process is accomplished by maintaining a groundbased mirror-image of spacecraft On-board Computer memory.

Quan, Alan↗
NASA NTRS1983

SP-100, a project manager's view

Born to meet the special needs of America's space effort, the SP-100 Program testifies to the cooperation among government agencies. The Department of Energy (DOE), the National Aeronautics and Space Administration (NASA), and the Defense Advanced Research Projects Agency (DARPA) are working together to produce a 100-kW power system for use in outer space. At this point in the effort, it is appropriate to review: The approach to meet program goals; the status of activities of the Project Office, managed by the Jet Propulsion Laboratory (JPL); and, because this is a meeting on materials, answers beings developed by the Project Office to vital questions on refractory alloy technology.

Truscello, Vincent C.↗
NASA NTRS1990

Synthetic aperture radar observations of the Greenland ice sheet

Results of preliminary analyses of aircraft polarimetric SAR data acquired over the Greenland Ice Sheet are presented. Data were collected in August 1989 by the Jet Propulsion Laboratory (JPL) multifrequency, polarimetric SAR using the NASA DC-8 aircraft over southern Greenland. Data of this kind are the first to be acquired over an ice sheet. They are complementary to the limited coverage provided by the SEASAT satellite SAR in 1978, and more recent aircraft X-band SAR image coverage. Frequency and polarization dependencies observed in the P-, L-, and C-band image products are attributed to large-scale variations in the snow and ice surface characteristics. At this time of year, during the ablation season, ice topography exerts a strong influence upon drainage and other hydrological features on the ice sheet surface. Systematic trends in backscatter strength observed across regions of changing snow facies are suggestive of a capability to map areas of snow wetness. Trends observed at C-band indicate that algorithms could possibly be developed which have the ability to delineate areas of significant melt.

Jezek, K.↗
NASA NTRS1990

Preliminary results from the MAESTRO 1 Campaign over the Black Forest

The Joint Research Center (JRC) Ispra and the European Space Agency (ESA) have co-sponsored the deployment of the National Aeronautics and Space Agency (NASA) and Jet Propulsion Laboratory (JPL), C-, L-, and P-band polarimetric synthetic aperture radar (SAR) in Europe in mid-August 1989. This deployment represents the first opportunity for European agencies and institutes to evaluate the current state of the art of multifrequency polarimetric imaging technology over European Test Sites. Of particular interest to the Joint Research Center (JRC) Ispra is the Black Forest Test Site at Freiburg in the Federal Republic of Germany. This Test Site incorporates the Villingen region of the Black Forest to the south-west of Germany. This paper reports upon the activities undertaken in preparation for the MAESTRO 1 Campaign in the Black Forest Test Site. In particular this paper reports upon the ground data collection campaign for the Freiburg Test Site where extensive and intensive ground data measurements were undertaken. These measurements were based upon standard ground data collection protocols developed for forestry by the JRC and utilized throughout Europe for the MAESTRO 1 Campaign. The paper then goes on to present preliminary results derived from the SAR data using the JRC-developed software for polarimetric data interpretation, POLTOOL.

Churchill, P. N.↗
NASA NTRS1994

Small Particles Intact Capture Experiment (SPICE)

The Small Particles Intact Capture Experiment (SPICE) will develop technologies and engineering techniques necessary to capture nearly intact, uncontaminated cosmic and interplanetary dust particles (IDP's). Successful capture of such particles will benefit the exobiology and planetary science communities by providing particulate samples that may have survived unaltered since the formation of the solar system. Characterization of these particles may contribute fundamental data to our knowledge of how these particles could have formed into our planet Earth and, perhaps, contributed to the beginnings of life. The term 'uncontaminated' means that captured cosmic and IDP particles are free of organic contamination from the capture process and the term 'nearly intact capture' means that their chemical and elemental components are not materially altered during capture. The key to capturing cosmic and IDP particles that are organic-contamination free and nearly intact is the capture medium. Initial screening of capture media included organic foams, multiple thin foil layers, and aerogel (a silica gel); but, with the exception of aerogel, the requirements of no contamination or nearly intact capture were not met. To ensure no contamination of particles in the capture process, high-purity aerogel was chosen. High-purity aerogel results in high clarity (visual clearness), a useful quality in detection and recovery of embedded captured particles from the aerogel. P. Tsou at the Jet Propulsion Laboratory (JPL) originally described the use of aerogel for this purpose and reported laboratory test results. He has flown aerogel as a 'GAS-can Lid' payload on STS-47 and is evaluating the results. The Timeband Capture Cell Experiment (TICCE), a Eureca 1 experiment, is also flying aerogel and is scheduled for recovery in late April.

Nishioka, Ken-Ji↗
NASA NTRS1994

Third International Symposium on Artificial Intelligence, Robotics, and Automation for Space 1994

The Third International Symposium on Artificial Intelligence, Robotics, and Automation for Space (i-SAIRAS 94), held October 18-20, 1994, in Pasadena, California, was jointly sponsored by NASA, ESA, and Japan's National Space Development Agency, and was hosted by the Jet Propulsion Laboratory (JPL) of the California Institute of Technology. i-SAIRAS 94 featured presentations covering a variety of technical and programmatic topics, ranging from underlying basic technology to specific applications of artificial intelligence and robotics to space missions. i-SAIRAS 94 featured a special workshop on planning and scheduling and provided scientists, engineers, and managers with the opportunity to exchange theoretical ideas, practical results, and program plans in such areas as space mission control, space vehicle processing, data analysis, autonomous spacecraft, space robots and rovers, satellite servicing, and intelligent instruments.

Source record↗
NASA NTRS1994

Commercialization of JPL Virtual Reality calibration and redundant manipulator control technologies

Within NASA's recent thrust for industrial collaboration, JPL (Jet Propulsion Laboratory) has recently established two technology cooperation agreements in the robotics area: one on virtual reality (VR) calibration with Deneb Robotics, Inc., and the other on redundant manipulator control with Robotics Research Corporation (RRC). These technology transfer cooperation tasks will enable both Deneb and RRC to commercialize enhanced versions of their products that will greatly benefit both space and terrestrial telerobotic applications.

Kim, Won S.↗
NASA NTRS1994

An operations and command systems for the extreme ultraviolet explorer

About 40% of the budget of a scientific spacecraft mission is usually consumed by Mission Operations & Data Analysis (MO&DA) with MO driving these costs. In the current practice, MO is separated from spacecraft design and comes in focus relatively late in the mission life cycle. As a result, spacecraft may be designed that are very difficult to operate. NASA centers have extensive MO expertise but often lessons learned in one mission are not exploited for other parallel or future missions. A significant reduction of MO costs is essential to ensure a continuing and growing access to space for the scientific community. We are addressing some of these issues with a highly automated payload operations and command system for an existing mission, the Extreme Ultraviolet Explorer (EUVE). EUVE is currently operated jointly by the Goddard Space Flight Center (GSFC), responsible for spacecraft operations, and the Center for Extreme Ultraviolet Astrophysics (CEA) of the University of California, Berkeley, which controls the telescopes and scientific instruments aboard the satellite. The new automated system is being developed by a team including personnel from the NASA Ames Research Center (ARC), the Jet Propulsion Laboratory (JPL) and the Center for EUV Astrophysics (CEA). An important goal of the project is to provide AI-based technology that can be easily operated by nonspecialists in AI. Another important goal is the reusability of the techniques for other missions. Models of the EUVE spacecraft need to be built both for planning/scheduling and for monitoring. In both cases, our modeling tools allow the assembly of a spacecraft model from separate sub-models of the various spacecraft subsystems. These sub-models are reusable; therefore, building mission operations systems for another small satellite mission will require choosing pre-existing modules, reparametrizing them with respect to the actual satellite telemetry information, and reassembling them in a new model. We briefly describe the EUVE mission and indicate why it is particularly suitable for the task. Then we briefly outline our current work in mission planning/scheduling and spacecraft and instrument health monitoring.

Muscettola, Nicola↗