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At least 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

STS-57 Space Shuttle mission report

The STS-57 Space Shuttle Program Mission Report provides a summary of the Payloads, as well as the Orbiter, External Tank (ET), Solid Rocket Booster (SRB), Redesigned Solid Rocket Motor (RSRM), and the Space Shuttle main engine (SSME) systems performance during the fifty-sixth flight of the Space Shuttle Program and fourth flight of the Orbiter vehicle Endeavour (OV-105). In addition to the Orbiter, the flight vehicle consisted of an ET (ET-58); three SSME's which were designated as serial numbers 2019, 2034, and 2017 in positions 1, 2, and 3, respectively; and two SRB's which were designated BI-059. The lightweight RSRM's that were installed in each SRB were designated as 360L032A for the left SRB and 360W032B for the right SRB. The STS-57 Space Shuttle Program Mission Report fulfills the Space Shuttle Program requirement, as documented in NSTS 07700, Volume 8, Appendix E. That document states that each major organizational element supporting the Program will report the results of their hardware evaluation and mission performance plus identify all related in-flight anomalies.

Fricke, Robert W., Jr.↗
NASA NTRS1993

STS-56 Space Shuttle mission report

The STS-56 Space Shuttle Program Mission Report provides a summary of the Payloads, as well as the Orbiter, External Tank (ET), Solid Rocket Booster (SRB), Redesigned Solid Rocket Motor (RSRM), and the Space Shuttle main engine (SSME) systems performance during the fifty-fourth flight of the Space Shuttle Program and sixteenth flight of the Orbiter vehicle Discovery (OV-103). In addition to the Orbiter, the flight vehicle consisted of an ET (ET-54); three SSME's, which were designated as serial numbers 2024, 2033, and 2018 in positions 1, 2, and 3, respectively; and two SRB's which were designated BI-058. The lightweight RSRM's that were installed in each SRB were designated as 360L031A for the left SRB and 360L031B for the right SRB.

Fricke, Robert W., Jr.↗
NASA NTRS1994

A high-speed linear algebra library with automatic parallelism

Parallel or distributed processing is key to getting highest performance workstations. However, designing and implementing efficient parallel algorithms is difficult and error-prone. It is even more difficult to write code that is both portable to and efficient on many different computers. Finally, it is harder still to satisfy the above requirements and include the reliability and ease of use required of commercial software intended for use in a production environment. As a result, the application of parallel processing technology to commercial software has been extremely small even though there are numerous computationally demanding programs that would significantly benefit from application of parallel processing. This paper describes DSSLIB, which is a library of subroutines that perform many of the time-consuming computations in engineering and scientific software. DSSLIB combines the high efficiency and speed of parallel computation with a serial programming model that eliminates many undesirable side-effects of typical parallel code. The result is a simple way to incorporate the power of parallel processing into commercial software without compromising maintainability, reliability, or ease of use. This gives significant advantages over less powerful non-parallel entries in the market.

Boucher, Michael L.↗
NASA NTRS1994

Technology transfer of operator-in-the-loop simulation

The technology developed for operator-in-the-loop simulation in space teleoperation has been applied to Caterpillar's backhoe, wheel loader, and off-highway truck. On an SGI workstation, the simulation integrates computer modeling of kinematics and dynamics, real-time computational and visualization, and an interface with the operator through the operator's console. The console is interfaced with the workstation through an IBM-PC in which the operator's commands were digitized and sent through an RS-232 serial port. The simulation gave visual feedback adequate for the operator in the loop, with the camera's field of vision projected on a large screen in multiple view windows. The view control can emulate either stationary or moving cameras. This simulator created an innovative engineering design environment by integrating computer software and hardware with the human operator's interactions. The backhoe simulation has been adopted by Caterpillar in building a virtual reality tool for backhoe design.

Yae, K. H.↗
NASA NTRS1994

STS-58 Space Shuttle Mission Report

The STS-58 Space Shuttle Program Mission Report provides a summary of the payload activities as well as the orbiter, external tank (ET), solid rocket booster (SRB) and redesigned solid rocket motor (RSRM), and the space shuttle main engine (SSME) subsystems performance during the fifty-eighth mission of the space shuttle program and fifteenth flight of the orbiter vehicle Columbia (OV-102). In addition to the orbiter, the flight vehicle consisted of an ET (ET-57); three SSME's, which were designated as serial numbers 2024, 2109, and 2018 in positions 1, 2, and 3, respectively; and two SRB's which were designated BI-061. The lightweight RSRM's that were installed in each SRB were designated as 360L034A for the left SRB and 360W034B for the right SRB.

Fricke, Robert W., Jr.↗
NASA NTRS1993

STS-51 Space Shuttle Mission Report

The STS-51 Space Shuttle Program Mission Report summarizes the payloads as well as the orbiter, external tank (ET), solid rocket booster (SRB), redesigned solid rocket motor (RSRM), and the space shuttle main engine (SSME) systems performance during the fifty-seventh flight of the space shuttle program and seventeenth flight of the orbiter vehicle Discovery (OV-103). In addition to the orbiter, the flight vehicle consisted of an ET designated as ET-59; three SSME's, which were designated as serial numbers 2031, 2034, and 2029 in positions 1, 2, and 3, respectively; and two SRB's which were designated BI-060. The lightweight RSRM's that were installed in each SRB were designated as 360W033A for the left SRB and 360L033B for the right SRB.

Fricke, Robert W., Jr.↗
NASA NTRS1993

A transient FETI methodology for large-scale parallel implicit computations in structural mechanics, part 2

Explicit codes are often used to simulate the nonlinear dynamics of large-scale structural systems, even for low frequency response, because the storage and CPU requirements entailed by the repeated factorizations traditionally found in implicit codes rapidly overwhelm the available computing resources. With the advent of parallel processing, this trend is accelerating because explicit schemes are also easier to parallellize than implicit ones. However, the time step restriction imposed by the Courant stability condition on all explicit schemes cannot yet and perhaps will never be offset by the speed of parallel hardware. Therefore, it is essential to develop efficient and robust alternatives to direct methods that are also amenable to massively parallel processing because implicit codes using unconditionally stable time-integration algorithms are computationally more efficient than explicit codes when simulating low-frequency dynamics. Here we present a domain decomposition method for implicit schemes that requires significantly less storage than factorization algorithms, that is several times faster than other popular direct and iterative methods, that can be easily implemented on both shared and local memory parallel processors, and that is both computationally and communication-wise efficient. The proposed transient domain decomposition method is an extension of the method of Finite Element Tearing and Interconnecting (FETI) developed by Farhat and Roux for the solution of static problems. Serial and parallel performance results on the CRAY Y-MP/8 and the iPSC-860/128 systems are reported and analyzed for realistic structural dynamics problems. These results establish the superiority of the FETI method over both the serial/parallel conjugate gradient algorithm with diagonal scaling and the serial/parallel direct method, and contrast the computational power of the iPSC-860/128 parallel processor with that of the CRAY Y-MP/8 system.

Farhat, Charbel↗
NASA NTRS1994

Preconditioned implicit solvers for the Navier-Stokes equations on distributed-memory machines

The GMRES method is parallelized, and combined with local preconditioning to construct an implicit parallel solver to obtain steady-state solutions for the Navier-Stokes equations of fluid flow on distributed-memory machines. The new implicit parallel solver is designed to preserve the convergence rate of the equivalent 'serial' solver. A static domain-decomposition is used to partition the computational domain amongst the available processing nodes of the parallel machine. The SPMD (Single-Program Multiple-Data) programming model is combined with message-passing tools to develop the parallel code on a 32-node Intel Hypercube and a 512-node Intel Delta machine. The implicit parallel solver is validated for internal and external flow problems, and is found to compare identically with flow solutions obtained on a Cray Y-MP/8. A peak computational speed of 2300 MFlops/sec has been achieved on 512 nodes of the Intel Delta machine,k for a problem size of 1024 K equations (256 K grid points).

Ajmani, Kumud↗
NASA NTRS1993

A high-speed lossless data compression system for space applications

This paper reports on the integration of a lossless data compression/decompression chipset into a space data system architecture. For its compression engine, the data system incorporates the Universal Source Encoder (USE) designed for the NASA/Goddard Space Flight Center. Currently, the data compression testbed generates video frames consisting of 512 lines of 512 pixels having 8-bit resolution. Each image is passed through the USE where the lines are internally partitioned into 16-word blocks. These blocks are adaptively encoded across widely varying entropy levels using a Rice 12-option set coding algorithm. The current system operates at an Input/Output rate of 10 Msamples/s or 80 Mbits/s for each buffered input line. Frame and line synchronization for each image are maintained through the use of uniquely decodable command words. Length information of each variable length compressed image line is also included in the output stream. The data and command information are passed to the next stage of the system architecture through a serial fiber-optic transmitter. The initial segment of this stage consists of packetizer hardware which adds an appropriate CCSDS header to the received source data. An uncompressed mode is optionally available to pass image lines directly to the packetizer hardware. A data decompression testbed has also been developed to confirm the data compression operation.

Miko, Joe↗
NASA NTRS1994

Long-term changes in the statistical distribution of Dobson total ozone in selected Northern Hemisphere geographical regions

The daily averages of total column amount of ozone taken in the period 1964-1988 at a network of 24 Dobson stations have been analyzed. Year-round data as well as summer data (May - Aug.) and winter data (Dec. - March) have been examined in the following regions: latitude bands (30 deg N - 39 deg N, 40 deg N - 52 deg N, 30 deg N - 60 deg N), North America, Europe, and Japan. To find year-to-year changes in the shape of the annual statistical distribution of total ozone (ASDTO) for these regions, we analyze trends in the following statistic characteristics of ASDTO: mean, standard deviation, median, and 10 and 90 percentiles. Time series of the statistical characteristics for the selected regions have been combined by averaging the individual stations values of these characteristics. The trends have been calculated by the multiple regression model adjusted for: the 11-year solar cycle, the Southern Oscillations effects, and for serial correlations. We have found that: a) in all regions (excluding Japan, North America), the shape of ASDTO has been drifting towards low ozone values. The drift seems to be not accompanied with a transformation in the shape of ASDTO. The drift speed (the rate of decrease in the annual means of total ozone) is of order 1-3 percent per decade (in the period 1970-1988). b) In Japan, the interannual changes in the shape of ASDTO have not been revealed. c) In North America, the drift of the year-round ASDTO (the year-round ASDTO comprises all the daily means of total ozone in a given year) has been accompanied with a transformation in the shape. The shape of the year round ASDTO becomes narrower. d) In all regions, except Japan and the band 30 deg - 39 deg N, the winter ASDTO (the winter ASDTO comprises the data taken in the period December in a given year through March next year) moves faster towards low ozone values than the summer ASDTO (the summer ASDTO comprises the data taken in the period May through August in a given year).

Krzyscin, Janusz W.↗
NASA NTRS1994

Robust inverse kinematics using damped least squares with dynamic weighting

This paper presents a general method for calculating the inverse kinematics with singularity and joint limit robustness for both redundant and non-redundant serial-link manipulators. Damped least squares inverse of the Jacobian is used with dynamic weighting matrices in approximating the solution. This reduces specific joint differential vectors. The algorithm gives an exact solution away from the singularities and joint limits, and an approximate solution at or near the singularities and/or joint limits. The procedure is here implemented for a six d.o.f. teleoperator and a well behaved slave manipulator resulted under teleoperational control.

Schinstock, D. E.↗
NASA NTRS1994

Thermal feedback in virtual reality and telerobotic systems

A new concept has been developed that allows temperature to be part of the virtual world. The Displaced Temperature Sensing System (DTSS) can 'display' temperature in a virtual reality system.The DTSS can also serve as a feedback device for telerobotics. For virtual reality applications the virtual world software would be required to have a temperature map of its world. By whatever means (magnetic tracker, ultrasound tracker, etc.) the hand and fingers, which have been instrumented with thermodes, would be tracked. The temperature associated with the current position would be transmitted to the DRSS via a serial data link. The DTSS would provide that temperature to the fingers. For telerobotic operation the function of the DTSS is to transmit a temperature from a remote location to the fingers where the temperature can be felt.

Zerkus, Mike↗
NASA NTRS1994

Test Telemetry And Command System (TTACS)

The Jet Propulsion Laboratory has developed a multimission Test Telemetry and Command System (TTACS) which provides a multimission telemetry and command data system in a spacecraft test environment. TTACS reuses, in the spacecraft test environment, components of the same data system used for flight operations; no new software is developed for the spacecraft test environment. Additionally, the TTACS is transportable to any spacecraft test site, including the launch site. The TTACS is currently operational in the Galileo spacecraft testbed; it is also being provided to support the Cassini and Mars Surveyor Program projects. Minimal personnel data system training is required in the transition from pre-launch spacecraft test to post-launch flight operations since test personnel are already familiar with the data system's operation. Additionally, data system components, e.g. data display, can be reused to support spacecraft software development; and the same data system components will again be reused during the spacecraft integration and system test phases. TTACS usage also results in early availability of spacecraft data to data system development and, as a result, early data system development feedback to spacecraft system developers. The TTACS consists of a multimission spacecraft support equipment interface and components of the multimission telemetry and command software adapted for a specific project. The TTACS interfaces to the spacecraft, e.g., Command Data System (CDS), support equipment. The TTACS telemetry interface to the CDS support equipment performs serial (RS-422)-to-ethernet conversion at rates between 1 bps and 1 mbps, telemetry data blocking and header generation, guaranteed data transmission to the telemetry data system, and graphical downlink routing summary and control. The TTACS command interface to the CDS support equipment is nominally a command file transferred in non-real-time via ethernet. The CDS support equipment is responsible for metering the commands to the CDS; additionally for Galileo, TTACS includes a real-time-interface to the CDS support equipment. The TTACS provides the basic functionality of the multimission telemetry and command data system used during flight operations. TTACS telemetry capabilities include frame synchronization, Reed-Solomon decoding, packet extraction and channelization, and data storage/query. Multimission data display capabilities are also available. TTACS command capabilities include command generation verification, and storage.

Fogel, Alvin J.↗
NASA NTRS1994

Small satellite space operations

CTA Space Systems has played a premier role in the development of the 'lightsat' programs of the 80's and 90's. The high costs and development times associated with conventional LEO satellite design, fabrication, launch, and operations continue to motivate the development of new methodologies, techniques, and generally low cost and less stringently regulated satellites. These spacecraft employ low power 'lightsat' communications (versus TDRSS for NASA's LEO's) and typically fly missions with payload/experiment suites that can succeed, for example, without heavily redundant backup systems and large infrastructures of personnel and ground support systems. Such small yet adaptable satellites are also typified by their very short contract-to-launch times (often one to two years). This paper reflects several of the methodologies and perspectives of our successful involvement in these innovative programs and suggests how they might relieve NASA's mounting pressures to reduce the cost of both the spacecraft and their companion mission operations. It focuses on the use of adaptable, sufficiently powerful yet inexpensive PC-based ground systems for wide ranging user terminal (UT) applications and master control facilities for mission operations. These systems proved themselves in successfully controlling more than two dozen USAF, USN, and ARPA satellites at CTA/SS. UT versions have linked with both GEO and LEO satellites and functioned autonomously in relay roles often in remote parts of the world. LEO applications particularly illustrate the efficacy of these concepts since a user can easily mount a lightweight antenna, usually an omni or helix with light duty rotors and PC-based drivers. A few feet of coax connected to a small transceiver module (the size of a small PC) and a serial line to an associated PC establishes a communications link and together with the PC constitute a viable ground station. Applications included geomagnetic mapping; spaceborne solid state recorder validation; global store-and-forward data communications for both scientific and military purposes such as Desert Storm; UHF transponder services for both digital data and voice using a constellation; remote sensor monitoring of weather and oceanographic conditions; classified payloads; and UHF spectrum surveillance. Ground processing has been accomplished by automatic unattended or manual operation. Management of multiple assets highlights the relative ease with which two constellations totaling nine satellites were controlled from one system including constellation station keeping. Our experience in small end-to-end systems including concurrent design, development, and testing of the flight and operational ground systems offers low cost approaches to NASA scientific satellite operations of the 1990's.

Reiss, Keith↗
NASA NTRS1994

Embedded parallel processing based ground control systems for small satellite telemetry

The use of networked terminals which utilize embedded processing techniques results in totally integrated, flexible, high speed, reliable, and scalable systems suitable for telemetry and data processing applications such as mission operations centers (MOC). Synergies of these terminals, coupled with the capability of terminal to receive incoming data, allow the viewing of any defined display by any terminal from the start of data acquisition. There is no single point of failure (other than with network input) such as exists with configurations where all input data goes through a single front end processor and then to a serial string of workstations. Missions dedicated to NASA's ozone measurements program utilize the methodologies which are discussed, and result in a multimission configuration of low cost, scalable hardware and software which can be run by one flight operations team with low risk.

Forman, Michael L.↗
NASA NTRS1994

Spacecraft Data Simulator for the test of level zero processing systems

The Microelectronic Systems Branch (MSB) at Goddard Space Flight Center (GSFC) has developed a Spacecraft Data Simulator (SDS) to support the development, test, and verification of prototype and production Level Zero Processing (LZP) systems. Based on a disk array system, the SDS is capable of generating large test data sets up to 5 Gigabytes and outputting serial test data at rates up to 80 Mbps. The SDS supports data formats including NASA Communication (Nascom) blocks, Consultative Committee for Space Data System (CCSDS) Version 1 & 2 frames and packets, and all the Advanced Orbiting Systems (AOS) services. The capability to simulate both sequential and non-sequential time-ordered downlink data streams with errors and gaps is crucial to test LZP systems. This paper describes the system architecture, hardware and software designs, and test data designs. Examples of test data designs are included to illustrate the application of the SDS.

Shi, Jeff↗
NASA NTRS1994

STS-65 Space Shuttle mission report

The STS-65 Space Shuttle Program Mission Report summarizes the Payload activities as well as the Orbiter, External Tank (ET), Solid Rocket Booster (SRB), Redesigned Solid Rocket Motor (RSRM), and the Space Shuttle main engine (SSME) systems performance during the sixty-third flight of the Space Shuttle Program and the seventeenth flight of the Orbiter vehicle Columbia (OV-102). In addition to the Orbits the flight vehicle consisted of an ET that was designated ET-64; three SSME's that were designated as serial numbers 2019, 2030, and 2017 in positions 1, 2, and 3, respectively; and two SRB's that were designated Bl-066. The RSRM's that were installed in each SRB were designated as 360P039A for the left SRB, and 360W039 for the right SRB. The primary objective of this flight was to complete the operation of the second International Microgravity Laboratory (IML-2). The secondary objectives of this flight were to complete the operations of the Commercial Protein Crystal Growth (CPCG), Orbital Acceleration Research Experiment (OARE), and the Shuttle Amateur Radio Experiment (SAREX) II payloads. Additional secondary objectives were to meet the requirements of the Air Force Maui Optical Site (AMOS) and the Military Application Ship Tracks (MAST) payloads, which were manifested as payloads of opportunity.

Fricke, Robert W., Jr.↗
NASA NTRS1994

A report of work activities on the NASA Spacelink public electronic library

NASA Spacelink is a comprehensive electronic data base of NASA and other source educational and informational materials. This service originates at Marshall Space Flight Center (MSFC) in Huntsville, Alabama. This is an education service of NASA Headquarters, through the MSFC Education Office, that first began in February of 1988. The new NASA Spacelink Public Electronic Library was the result of a study conducted to investigate an upgrade or redesign of the original NASA Spacelink. The UNIX Operating System was chosen to be the host operating system for the new NASA Spacelink Public Electronic Library. The UNIX system was selected for this project because of the strengths built into the embedded communication system and for its simple and direct file handling capabilities. The host hardware of the new system is a Sun Microsystems SPARCserver 1000 computer system. The configuration has four 50-MHz SuperSPARC processors with 128 megabytes of shared memory; three SB800 serial ports allowing 24 cable links for phone communications; 4.1 gigabytes of on-line disk storage; and ten (10) CD-ROM drives. Communications devices on the system are sufficient to support the expected number of users through the Internet, the local dial services, long distance dial services; the MSFC PABX, and the NPSS (NASA Packet Switching System) and 1-800 access service for the registered teachers.

Smith, Willard A.↗