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At least 1,081 records · Page 60
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Facilities and programs for research in a low-gravity environment

The history of NASA-supported microgravity material-processing research on Apollo, Skylab, and Apollo-Soyuz is reviewed; the currently available ground and Space Shuttle laboratory facilities are characterized and illustrated with drawings; and an overview of the Microgravity Science and Applications Program (MSAP) is given. The ground systems include drop tubes, drop towers, aircraft, and levitators; on the Space Shuttle, facilities are provided in the Orbiter middeck, in the payload bay, and in the Spacelab module. The aims of MSAP and the mechanisms for academic or industry participation are outlined, and typical results of MSAP-organized research in electronic materials, biotechnology, metals and alloys, glasses and ceramics, combustion, fluid dynamics, and transport phenomena are summarized.

Halpern, Richard E.↗
NASA NTRS1987

The challenge of logistics facilities development

The paper discusses the experiences of a group of engineers and logisticians at John F. Kennedy Space center in the design, construction and activation of a consolidated logistics facility for support of Space Transportation System ground operations and maintenance. The planning, methodology and processes are covered, with emphasis placed on unique aspects and lessons learned. The project utilized a progressive design, baseline and build concept for each phase of construction, with the Government exercising funding and configuration oversight.

Davis, James R.↗
NASA NTRS1987

The planned Alaska SAR Facility - An overview

The Alaska SAR Facility (ASF) is described in an overview fashion. The facility consists of three major components, a Receiving Ground System, a SAR Processing System and an Analysis and Archiving System; the ASF Program also has a Science Working Team and the requisite management and operations systems. The ASF is now an approved and fully funded activity; detailed requirements and science background are presented for the facility to be implemented for data from the European ERS-1, the Japanese ERS-1 and Radarsat.

Carsey, Frank↗
NASA NTRS1988

Knowledge based tools for Hubble Space Telescope planning and scheduling: Constraints and strategies

The Hubble Space Telescope (HST) presents an especially challenging scheduling problem since a year's observing program encompasses tens of thousands of exposures facing numerous coupled constraints. Recent progress in the development of planning and scheduling tools is discussed which augment the existing HST ground system. General methods for representing activities, constraints, and constraint satisfaction, and time segmentation were implemented in a scheduling testbed. The testbed permits planners to evaluate optimal scheduling time intervals, calculate resource usage, and to generate long and medium range plans. Graphical displays of activities, constraints, and plans are an important feature of the system. High-level scheduling strategies using rule based and neural net approaches were implemented.

Miller, Glenn↗
NASA NTRS1989

Middeck Active Control Experiment (MACE), phase A

A rationale to determine which structural experiments are sufficient to verify the design of structures employing Controlled Structures Technology was derived. A survey of proposed NASA missions was undertaken to identify candidate test articles for use in the Middeck Active Control Experiment (MACE). The survey revealed that potential test articles could be classified into one of three roles: development, demonstration, and qualification, depending on the maturity of the technology and the mission the structure must fulfill. A set of criteria was derived that allowed determination of which role a potential test article must fulfill. A review of the capabilities and limitations of the STS middeck was conducted. A reference design for the MACE test article was presented. Computing requirements for running typical closed-loop controllers was determined, and various computer configurations were studied. The various components required to manufacture the structure were identified. A management plan was established for the remainder of the program experiment development, flight and ground systems development, and integration to the carrier. Procedures for configuration control, fiscal control, and safety, reliabilty, and quality assurance were developed.

Crawley, Edward F.↗
NASA NTRS1988

GPS-based precision orbit determination - A Topex flight experiment

Plans for a Topex/Poseiden flight experiment to test the accuracy of using GPS data for precision orbit determination of earth satellites are presented. It is expected that the GPS-based precision orbit determination will provide subdecimeter accuracies in the radial component of the Topex orbit when the extant gravity model is tuned for wavelengths longer than about 1000 kms. The concept, design, flight receiver, antenna system, ground processing, and data processing of GPS are examined. Also, an accurate quasi-geometric orbit determination approach called nondynamic or reduced dynamic tracking which relies on the use of the pseudorange and the carrier phase measurements to reduce orbit errors arising from mismodeled dynamics is discussed.

Melbourne, William G.↗
NASA NTRS1990

NASA's first dexterous space robot

NASA is developing the Flight Telerobotic Servicer (FTS), a robotic device that can be teleoperated under constant command of a human operator or run by itself under human supervision. Plans call for the FTS to assist the astronauts in the assembly, maintenance, servicing, and inspection of Space Station Freedom. The FTS project is driven by five major objectives: to reduce Space Station dependence on crew EVA, improve crew safety, enhance crew utilization, promote remote servicing capabilities for platforms, and accelerate technology transfer from research to U.S. industry. Another part of the FTS project is a ground system that will support operations and system evolution. Not only will the FTS provide a needed operational capability during the assembly and operation of Space Station Freedom, it will also provide an expanding foundation for proving more advanced robotic and telepresence concepts in space.

Mccain, Harry G.↗
NASA NTRS1989

Asteroid observations with the Hubble Space Telescope and the Space Infrared Telescope Facility

The ways that the asteroids can be studied with the Hubble Space Telescope (HST) and the Space Infrared Telescope Facility (SIRTF) are examined. Spectrophotometry of asteroids and the study of asteroid surfaces, shape, spins, configuration, normal reflectance, and limb darkening of asteroids using the HST are addressed along with the detection of asteroid satellites and the discovery of small asteroids using the HST. The relation of the HST to its ground system is described, as are the spectrophotometric instruments of the HST. Imaging with the HST using the Faint Object Camera and the Wide Field and Planetary Camera is examined. Finally, the SIRTF observatory, instrumentation, and capabilities for solar system science are discussed.

Zellner, B.↗
NASA NTRS1990

Launch site integration for mixed fleet operations

Launch site impacts and integration planning issues are presented to support launch operations for a mixed vehicle fleet (manned and cargo). Proposed ground systems and launch site configurations are described. Prelaunch processing scenarios and schedules are developed for candidate launch vehicles. Earth-to-orbit (ETO) vehicle architectures are presented to meet future launch requirements, including the Space Exploration Initiative (SEI). Flight vehicle design recommendations to enhance launch processing are discussed. The significance of operational designs for future launch vehicles is shown to be a critical factor in planning for mixed fleet launch site operations.

Scott, L. P.↗
NASA NTRS1991

Space station control center architecture

The Space Station control center (SSCC) is under the cognizance of the Johnson Space Center and is located adjacent to the Shuttle's mission control center. Responsibility for design, development, and operations of the control center is the responsibility of the mission operations directorate at JSC. Space Station Ground Systems Division is responsible for design and development of the control center systems which is currently in process under the mission support contractor team led by Loral Space Information Systems. It is early in the life cycle of the SSCC project. System functional design review was completed. Subsystem requirements are now being developed and reviewed. A new facility will be available for development activities.

Schmalz, Karen↗
NASA NTRS1991

Geostationary Operational Environmental Statellite(GEOS-N report)

The Advanced Missions Analysis Office (AMAO) of GSFC has completed a study of the Geostationary Operational Environmental Satellites (GOES-N) series. The feasibility, risks, schedules, and associated costs of advanced space and ground system concepts responsive to National Oceanic and Atmospheric Administration (NOAA) requirements were evaluated. The study is the first step in a multi-phased procurement effort that is expected to result in launch ready hardware in the post 2000 time frame. This represents the latest activity of GSFC in translating meteorological requirements of NOAA into viable space systems in geosynchronous earth orbits (GEO). GOES-N represents application of the latest spacecraft, sensor, and instrument technologies to enhance NOAA meteorological capabilities via remote and in-situ sensing from GEO. The GOES-N series, if successfully developed, could become another significant step in NOAA weather forecasting space systems, meeting increasingly complex emerging national needs for that agency's services.

Source record↗
NASA NTRS1990

Tropical Rainfall Measuring Mission (TRMM). Phase B: Data capture facility definition study

The National Aeronautics and Aerospace Administration (NASA) and the National Space Development Agency of Japan (NASDA) initiated the Tropical Rainfall Measuring Mission (TRMM) to obtain more accurate measurements of tropical rainfall then ever before. The measurements are to improve scientific understanding and knowledge of the mechanisms effecting the intra-annual and interannual variability of the Earth's climate. The TRMM is largely dependent upon the handling and processing of the data by the TRMM Ground System supporting the mission. The objective of the TRMM is to obtain three years of climatological determinations of rainfall in the tropics, culminating in data sets of 30-day average rainfall over 5-degree square areas, and associated estimates of vertical distribution of latent heat release. The scope of this study is limited to the functions performed by TRMM Data Capture Facility (TDCF). These functions include capturing the TRMM spacecraft return link data stream; processing the data in the real-time, quick-look, and routine production modes, as appropriate; and distributing real time, quick-look, and production data products to users. The following topics are addressed: (1) TRMM end-to-end system description; (2) TRMM mission operations concept; (3) baseline requirements; (4) assumptions related to mission requirements; (5) external interface; (6) TDCF architecture and design options; (7) critical issues and tradeoffs; and (8) recommendation for the final TDCF selection process.

Source record↗
NASA NTRS1992

Reduced lymphocyte activation in space - Role of cell-substratum interactions

The effect of substratum adhesiveness on lymphocyte responsiveness was investigated by reducing and blocking cell adhesion with poly-HEMA in a simple on ground system. Cells grown on medium thick and thick poly-HEMA films were rounded in shape and displayed no signs of spreading. By contrast, on tissue culture plastic and very thin poly-HEMA films, they showed clear signs of spreading. The mitogenic response of lymphocytes grown on thick poly-HEMA films was reduced by up to 68 percent of the control (tissue culture plastic). Interferon gamma production was virtually nil when the cells were grown on the least adhesive substratum. These results show that activated lymphocytes need to anchor and spread prior to achieving an optimal proliferation response. It is concluded that decreased lymphocyte adhesion could contribute to the depressed in vitro lymphocyte responsiveness found in the microgravity conditions of space flight.

Gmuender, F. K.↗
NASA NTRS1991

The Upper Atmosphere Research Satellite (UARS)

The mission and instruments of the Upper Atmosphere Research Satellite (UARS) are discussed. The individual experiments that will measure energy input to the atmosphere, temperature and important trace chemical species, and winds are individually described. The ground system, correlative measurements, data analysis, and theoretical studies are addressed.

Reber, Carl A.↗
NASA NTRS1989

Launch site integration of Liquid Rocket Boosters

The impacts of introducing Liquid Rocket Boosters (LRB) into the STS/KSC launch environment are identified and evaluated. Proposed ground systems configurations are presented along with a launch site requirements summary. Pre-launch processing scenarios are described and the required facility modifications and new facility requirements are analyzed. Flight vehicle design recommendations to enhance launch processing are discussed. Processing approaches to integrate LRB with existing STS launch operations are evaluated. The key features and significance of launch site transition to a new STS configuration in parallel with ongoing launch activities are enumerated.

Scott, Leland P.↗
NASA NTRS1991

Differential tracking data types for accurate and efficient Mars planetary navigation

Ways in which high-accuracy differential observations of two or more deep space vehicles can dramatically extend the power of earth-based tracking over conventional range and Doppler tracking are discussed. Two techniques - spacecraft-spacecraft differential very long baseline interferometry (S/C-S/C Delta(VLBI)) and same-beam interferometry (SBI) - are discussed. The tracking and navigation capabilities of conventional range, Doppler, and quasar-relative Delta(VLBI) are reviewed, and the S/C-S/C Delta (VLBI) and SBI types are introduced. For each data type, the formation of the observable is discussed, an error budget describing how physical error sources manifest themselves in the observable is presented, and potential applications of the technique for Space Exploration Initiative scenarios are examined. Requirements for spacecraft and ground systems needed to enable and optimize these types of observations are discussed.

Edwards, C. D., Jr.↗
NASA NTRS1992

Application of high-precision two-way ranging to Galileo Earth-1 encounter navigation

The application of precision two-way ranging to orbit determination with relatively short data arcs is investigated for the Galileo spacecraft's approach to its first Earth encounter (December 8, 1990). Analysis of previous S-band (2.3-GHz) ranging data acquired from Galileo indicated that under good signal conditions submeter precision and 10-m ranging accuracy were achieved. It is shown that ranging data of sufficient accuracy, when acquired from multiple stations, can sense the geocentric angular position of a distant spacecraft. A range data filtering technique, in which explicit modeling of range measurement bias parameters for each station pass is utilized, is shown to largely remove the systematic ground system calibration errors and transmission media effects from the Galileo range measurements, which would otherwise corrupt the angle-finding capabilities of the data. The accuracy of the Galileo orbit solutions obtained with S-band Doppler and precision ranging were found to be consistent with simple theoretical calculations, which predicted that angular accuracies of 0.26-0.34 microrad were achievable. In addition, the navigation accuracy achieved with precision ranging was marginally better than that obtained using delta-differenced one-way range (delta DOR), the principal data type that was previously used to obtain spacecraft angular position measurements operationally.

Pollmeier, V. M.↗