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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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At least 1,639 records · Page 91
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Advanced technology for the Space Station

The goals and objectives of the Space Station Advanced Development Program are discussed. Data from tests and experiments in the areas of attitude control and stabilization, communications and tracking, data management systems, man systems, mechanisms, power systems, structures, thermal systems, and EVA are examined. The approaches used to implement these programs and for data transfer are described. The plans for the development of the Space Station are presented.

Nolan, Mark B.↗
NASA NTRS1986

20 kHz Space Station power system

The Space Station represents the next major U.S. commitment in space. The efficient delivery of power to multiple user loads is key to that success. In 1969, NASA Lewis Research Center began a series of studies with component and circuit developments that led to the high frequency bi-directional, four quadrant resonant driven converter. Additional studies and subsequent developments into the early 1980's have shown how the high frequency ac power system could provide overall advantages to many aerospace power systems. Because of its wide versatility, it also has outstanding advantages for the Space Station Program and its wide range of users. High frequency ac power provides higher efficiency, lower cost, and improved safety. The 20 kHz power system has exceptional flexibility, is inherently user friendly, and is compatible with all types of energy sources - photovoltaic, solar dynamic, rotating machines or nuclear Lewis distribution system testbed. The testbed demonstrates flexibility, versatility, and transparency to user technology as well as high efficiency, low mass, and reduced volume.

Hansen, Irving G.↗
NASA NTRS1987

Development of a prototype two-phase thermal bus system for Space Station

This paper describes the basic elements of a pumped two-phase ammonia thermal control system designed for microgravity environments, the development of the concept into a Space Station flight design, and design details of the prototype to be ground-tested in the Johnson Space Center (JSC) Thermal Test Bed. The basic system concept is one of forced-flow heat transport through interface heat exchangers with anhydrous ammonia being pumped by a device expressly designed for two-phase fluid management in reduced gravity. Control of saturation conditions, and thus system interface temperatures, is accomplished with a single central pressure regulating valve. Flow control and liquid inventory are controlled by passive, nonelectromechanical devices. Use of these simple control elements results in minimal computer controls and high system reliability. Building on the basic system concept, a brief overview of a potential Space Station flight design is given. Primary verification of the system concept will involve testing at JSC of a 25-kW ground test article currently in fabrication.

Myron, D. L.↗
NASA NTRS1987

Data storage systems technology for the Space Station era

The paper presents the results of an internal NASA study to determine if economically feasible data storage solutions are likely to be available to support the ground data transport segment of the Space Station mission. An internal NASA effort to prototype a portion of the required ground data processing system is outlined. It is concluded that the requirements for all ground data storage functions can be met with commercial disk and tape drives assuming conservative technology improvements and that, to meet Space Station data rates with commercial technology, the data will have to be distributed over multiple devices operating in parallel and in a sustained maximum throughput mode.

Dalton, John↗
NASA NTRS1987

The Space Station software support environment - Not just what, but why

The NASA environment is described with attention given to mission data systems in NASA and the strategic view. Space Station data systems are characterized into the following: distributed data systems, functionality and complexity, session oriented user interface, and distributed software development. The concept of a support software environment within the Space Station Program is elucidated and a strategic model for integrated data processing is presented.

Garman, John R.↗
NASA NTRS1987

Space Station Information System integrated communications concept

This paper presents a model for integrated communications within the Space Station Information System (SSIS). The SSIS is generally defined as the integrated set of space and ground information systems and networks which will provide required data services to the Space Station flight crew, ground operations personnel, and customer communities. This model is based on the International Standards Organization (ISO) layered model for Open Systems Interconnection (OSI). The requirements used to develop the model are presented, and the various elements of the model described.

Muratore, J.↗
NASA NTRS1987

Space Station Information System requirements for integrated communications

Space Station Information System (SSIS) requirements for integrated end-to-end communications are presented. The SSIS is defined as the integrated set of space and ground data and information systems and networks which will provide required data services to the Space Station flight crew, ground operations personnel, and customer communities. This model is based on the International Standards Organization (ISO) layered model for Open System Interconnection (OSI). These SSIS requirements include grades of service, priority classifications, systems management, flow control, bandwidth allocation, and standard SSIS data services.

Marker, W.↗
NASA NTRS1988

Adaptive Control For Space-Station Joints

Input gain weighting added to existing adaptive-control algorithm. Report discusses concept for adaptive control of rotations of various appended structures about joints on space station, with suppression of vibrations in both station and appendages. Concept relevant to such terrestrial applications as control of aircraft, suppression of vibrations in large buildings, and robotics.

Ih, Che-Hang Charles↗
NASA NTRS1987

Space station integrated wall design and penetration damage control

The analysis code BUMPER executes a numerical solution to the problem of calculating the probability of no penetration (PNP) of a spacecraft subject to man-made orbital debris or meteoroid impact. The codes were developed on a DEC VAX 11/780 computer that uses the Virtual Memory System (VMS) operating system, which is written in FORTRAN 77 with no VAX extensions. To help illustrate the steps involved, a single sample analysis is performed. The example used is the space station reference configuration. The finite element model (FEM) of this configuration is relatively complex but demonstrates many BUMPER features. The computer tools and guidelines are described for constructing a FEM for the space station under consideration. The methods used to analyze the sensitivity of PNP to variations in design, are described. Ways are suggested for developing contour plots of the sensitivity study data. Additional BUMPER analysis examples are provided, including FEMs, command inputs, and data outputs. The mathematical theory used as the basis for the code is described, and illustrates the data flow within the analysis.

Coronado, A. R.↗
NASA NTRS1986

Space station assembly/servicing capabilities

The aim is to place a permanently manned space station on-orbit around the Earth, which is international in scope. The program is nearing the close of the system definition and preliminary design phase. The first shuttle launch for space station assembly on-orbit is estimated for January 1993. Topics perceived to be important to on-orbit assembly and servicing are discussed. This presentation is represented by charts.

Joyce, Joseph↗
NASA NTRS1987

Solar-terrestrial research in the space station era

Because of the immense size of the solar-terrestrial system and its tightly-coupled physical nature, its study requires a carefully planned and coordinated approach using a variety of observational techniques. Of fundamental importance is the simultaneous measurement of the varying Sun, the solar wind, and the Earth's magnetosphere and atmosphere. These multiple measurements require a multi-spacecraft approach with both remote sensing of the Sun and atmosphere and in-situ measurements of the solar wind and magnetosphere. The decade of the 1990s will bring an opportunity to carry out the simultaneous set of measurements using a combination of instruments on missions such as the International Solar Terrestrial Physics Program, the GOES satellites, and the Space Station. For the first time it will be possible to determine solar variability and to sample the response of the solar wind and geospace portion of the environment in a thorough way. The potential opportunities for solar-terrestrial studies during the coming era of the Space Station are disclosed.

Chappell, Charles R.↗
NASA NTRS1986

Contamination control concepts for space station customer servicing

The customer servicing operations envisioned for the space station, which include instrument repair, orbital replacement unit (ORU) changeout, and fluid replenishment for free-flying and attached payloads, are expected to create requirements for a unique contamination control subsystem for the customer servicing facility (CSF). Both the core space station and the CSF users present unique requirements/sensitivities, not all of which are currently defined with common criteria. Preliminary results from an assessment of the effects of the CSF-induced contamination environment are reported. Strategies for a comprehensive contamination control approach and a description of specific hardware devices and their applicability are discussed.

Maruya, K. A.↗
NASA NTRS1987

Space station propulsion

Two propulsion systems have been selected for the space station: gaseous H/O rockets for high thrust applications and the multipropellant resistojets for low thrust needs. These two thruster systems integrate very well with the fluid systems on the space station, utilizing waste fluids as their source of propellant. The H/O rocket will be fueled by electrolyzed water and the resistojets will use waste gases collected from the environmental control system and the various laboratories. The results are presented of experimental efforts with H/O and resistojet thrusters to determine their performance and life capability, as well as results of studies to determine the availability of water and waste gases.

Jones, Robert E.↗
NASA NTRS1987

An assessment of clinical chemical sensing technology for potential use in space station health maintenance facility

A Health Maintenance Facility is currently under development for space station application which will provide capabilities equivalent to those found on Earth. This final report addresses the study of alternate means of diagnosis and evaluation of impaired tissue perfusion in a microgravity environment. Chemical data variables related to the dysfunction and the sensors required to measure these variables are reviewed. A technology survey outlines the ability of existing systems to meet these requirements. How the candidate sensing system was subjected to rigorous testing is explored to determine its suitability. Recommendations for follow-on activities are included that would make the commercial system more appropriate for space station applications.

Source record↗
NASA NTRS1987

Dobson-stations performance assessment using TOMS data

Examples of comparisons of monthly summaries (based on daily measurements) of some of the regularily operating Dobson stations, with the values deduced from the Total Ozone Mapping Spectrometer (TOMS) overpass are given. Shortcomings in certain Dobson stations are identified, such as: use of an incorrect value for the extraterrestrial constant (HOBART); sudden large volume changes (Brisbane); unusually low Dobson readings (Mauna Loa); and use of inaccurate cloud blue sky charts, causing fictitious differences with direct sun measurements (Toronto).

Bojkov, Rumen D.↗
NASA NTRS1987

High data rate modem simulation for the space station multiple-access communications system

The communications system for the space station will require a space based multiple access component to provide communications between the space based program elements and the station. A study was undertaken to investigate two of the concerns of this multiple access system, namely, the issues related to the frequency spectrum utilization and the possibilities for higher order (than QPSK) modulation schemes for use in possible modulators and demodulators (modems). As a result of the investigation, many key questions about the frequency spectrum utilization were raised. At this point, frequency spectrum utilization is seen as an area requiring further work. Simulations were conducted using a computer aided communications system design package to provide a straw man modem structure to be used for both QPSK and 8-PSK channels.

Horan, Stephen↗
NASA NTRS1987

Space station software reliability analysis based on failures observed during testing at the multisystem integration facility

Quality of software not only is vital to the successful operation of the space station, it is also an important factor in establishing testing requirements, time needed for software verification and integration as well as launching schedules for the space station. Defense of management decisions can be greatly strengthened by combining engineering judgments with statistical analysis. Unlike hardware, software has the characteristics of no wearout and costly redundancies, thus making traditional statistical analysis not suitable in evaluating reliability of software. A statistical model was developed to provide a representation of the number as well as types of failures occur during software testing and verification. From this model, quantitative measure of software reliability based on failure history during testing are derived. Criteria to terminate testing based on reliability objectives and methods to estimate the expected number of fixings required are also presented.

Tamayo, Tak Chai↗