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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 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

The NASA End-to-End Data System program

NASA has embarked on the NASA End-to-End Data System (NEEDS) program, the objective of which is to improve effectiveness and efficiency of NASA's data/information management system. Technology gaps and bottlenecks in the end-to-end system, which encompasses acquiring data, processing it, and converting it to useful information, will be identified. Technology development activities addressing these problem areas will be carried out and new technology will be implemented. Phase I, started in 1977, addresses some very near-term data handling and processing problems with the development of some subsystem components. Phase II, with a late 1978 start, will concentrate on complete subsystems developments to effect near real-time data management. Potential future phases are projected to revolve around the themes of low cost data distribution and a full system demonstration.

Price, R. D.↗
NASA NTRS1978

'Smart' from a NEEDS perspective

A description is presented of the characteristics which are considered essential for the NASA information system if it is to satisfy the sensor/user needs of the 1980's. The present data/information (DI) system is a complex arrangement of functions which has evolved to meet the increased demands placed upon it by the changing nature of the space program. Even though today's ground system is handling today's DI flow, it has certain limitations, and in some cases lacks consistency in organization and structure that would allow it to cope with the new requirements. A systematic analysis and overview of the total system is necessary for the planning of an efficient and effective information system for the 1980's. The NASA End-to-End Data System (NEEDS) program is an attempt to significantly increase the effectiveness and efficiency of the system that couples the user of the space data with the sensors.

Blanchard, D. L.↗
NASA NTRS1978

Impact of advanced onboard processing concepts on end-to-end data system

An investigation is conducted of the impact of advanced onboard data handling concepts on the total system in general and on ground processing operations, such as those being performed in the central data processing facility of the NASA Goddard Space Flight Center. In one of these concepts, known as the instrument telemetry packet (ITP) system, telemetry data from a single instrument is encoded into a packet, along with other ancillary data, and transmitted in this form to the ground. Another concept deals with onboard temporal registration of image data from such sensors as the thematic mapper, to be carried onboard the Landsat-D spacecraft in 1981. It is found that the implementation of the considered concepts will result in substantial simplification of the ground processing element of the system. With the projected tenfold increase in the data volume expected in the next decade, the introduction of ITP should keep the cost of the ground data processing function within reasonable bounds and significantly contribute to a more timely delivery of data/information to the end user.

Sos, J. Y.↗
NASA NTRS1978

The Seasat-A synthetic aperture radar design and implementation

The Seasat-A Synthetic Aperture Imaging Radar System is the first imaging radar system intended to be used as a scientific instrument designed for orbital use. The requirement of the radar system is to generate continuous radar imagery with a 100 kilometer swath with 25 meter resolution from an orbital altitude of 800 kilometers. These requirements impose unique system design problems and a description of the implementation will be given. The end-to-end data system will be described, including interactions of the spacecraft, antenna, sensor, telemetry link, recording subsystem, and data processor. Some of the factors leading to the selection of critical system parameters will be listed. The expected error sources leading to degradation of image quality will be described as well as estimates given of the expected performance from data obtained during ground testing of the completed subsystems.

Jordan, R.↗
NASA NTRS1978

Landsat-D - A systems overview

Landsat D, scheduled for launch in 1981, is designed to be a complete end-to-end highly automated data gathering and processing system providing a major step forward in global remote sensing for earth resources applications. This paper discusses the major components of the flight segment (the Multimission Modular Spacecraft, the Thematic Mapper and the Multispectral Scanner Subsystem) and of the ground segment (the Data Management System and the Landsat-D Assessment System). Descriptions and diagrams illustrating various aspects of flight and ground segments are provided.

Salomonson, V. V.↗
NASA NTRS1978

Data processing in infrared astronomy

Infrared astronomy is often carried out with rocket probes or orbiting satellite telescopes in order to escape the effects of atmospheric absorption. The data returned from such missions is a highly abstracted digital representation of measurements made by analog detectors. The ability to extract infrared-emission information from these data streams depends on a thorough understanding of the information flow from the telescope aperture to the computer center. This paper reviews the primary elements of this end-to-end concept and the impact of each of these elements on the data processing algorithms, including the division between onboard and ground processing for scientific measurements.

Pelzmann, R. F., Jr.↗
NASA NTRS1979

An end-to-end command and control concept for NASA data systems

Spacecraft command and control are currently taking on the characteristics of general computer-to-computer interprocess communication. The evolution of these systems during the 1980s will give NASA a true general-purpose end-to-end data request capability for the first time. This concept is presented in outline, with consideration of many of the detailed analyses and subsystem tradeoffs being performed as part of the NEEDS (NASA End-to-End Data System) program.

Desjardins, R.↗
NASA NTRS1978

End-to-End Information System design at the NASA Jet Propulsion Laboratory

In recognition of a pressing need of the 1980s to optimize the two-way flow of information between a ground-based user and a remote-space-based sensor, an end-to-end approach to the design of information systems has been adopted at the JPL. This paper reviews End-to-End Information System (EEIS) activity at the JPL, with attention given to the scope of the EEIS transfer function, and functional and physical elements of the EEIS. The relationship between the EEIS and the NASA End-to-End Data System program is discussed.

Hooke, A. J.↗
NASA NTRS1978

A concept for a transparent data acquisition and distribution system for spaceflight applications

The paper describes the Modular Data System concept of the NASA End-to-End Data System program. Data from a single instrument along with the necessary ancillary data will be assembled into self-contained packets and subsequently transmitted over various communications links (space telemetry channel, ground communications circuits, etc.) to the experimenter's facility in real time; reliable error control coding will be included in each link transmission to protect the integrity of the data packets. A major objective is to make the entire data acquisition and distribution process transparent to the experimenter in the sense that the output terminal of the distribution system will be physically, logically and electrically identical to that of the experiment output channel.

Greene, E. P.↗
NASA NTRS1978

Packet telemetry - A possible standard protocol for spacecraft data handling

Packetized telemetry-handling offers an opportunity to standardize major portions of the spacecraft-to-ground interface for future NASA missions. An end-to-end packet transport protocol is proposed which enables delivery of telemetry data from a remote space sensor to a ground-based user with virtually no project-unique intermediate processing. This paper reviews the possibility of creating a single telemetry format standard for both deep-space and near-earth missions. The proposed standard addresses the greatest NASA problem of the coming decade - cost - by allowing telemetry streams from many inflight spacecraft to be handled on the ground by common, simple, multimission processing elements.

Greenberg, E.↗
NASA NTRS1978

Advanced marine information delivery

The paper examines the information delivery challenges of the follow-on programs to Seasat-1 as they may progress through the next decade. These challenges include coping with the vast amounts of data to be transferred, fulfilling the temporal requirements on data delivery, and the tradeoffs and developments needed to accomplish the various levels of processing required to convert sensor output into useful information. A need for critical development is clearly identifiable in the areas of (1) low cost ground terminals capable of image extraction and image correlation; (2) dynamic data assimilation to accommodate forecasters; (3) low resolution onboard correlators; and (4) low cost user advisory (display) terminals. The system planners for the Ocean Satellite advanced programs are using an end-to-end data systems approach in meeting these challenges.

Durstenfeld, R.↗
NASA NTRS1978

Data Systems Dynamic Simulation - A total system for data system design assessments and trade studies

Data Systems Dynamic Simulation is a simulation system designed to reduce cost and time and increase the confidence and comprehensiveness of Data Systems Simulation. It is designed to simulate large data processing and communications systems from end-to-end or by subsystem. Those features relevant to system timing, control, sizing, personnel support activities, cost and external influences are modeled. Emphasis is placed on ease of use, comprehensive system performance measures, and extensive post simulation analysis capability. The system has been used to support trade studies of the NASA data system needs in the 1985 to 1990 time frame.

Hooper, J. W.↗
NASA NTRS1979

Seasat low-rate data system

The Seasat low-rate data system, an end-to-end data-processing and data-distribution system for the four low-rate sensors (radar altimeter, Seasat-A scatterometer system, scanning multichannel microwave radiometer, and visible and infrared radiometer) carried aboard the satellite, is discussed. The function of the distributed, nonreal-time, magnetic-tape system is to apply necessary calibrations, corrections, and conversions to yield geophysically meaningful products from raw telemetry data. The algorithms developed for processing data from the different sensors are described, together with the data catalogs compiled.

Brown, J. W.↗
NASA NTRS1979

Information adaptive system of NEEDS

The NASA End-to-End Data System (NEEDS) program was initiated by NASA to improve significantly the state of the art in acquisition, processing, and distribution of space-acquired data for the mid-1980s and beyond. The information adaptive system (IAS) is a program element under NEEDS Phase II which addresses sensor specific processing on board the spacecraft. The IAS program is a logical first step toward smart sensors, and IAS developments - particularly the system components and key technology improvements - are applicable to future smart efforts. The paper describes the design goals and functional elements of the IAS. In addition, the schedule for IAS development and demonstration is discussed.

Howle, W. M., Jr.↗
NASA NTRS1979

A grouped binary time code for telemetry and space applications

A computer oriented time code designed for users with various time resolution requirements is presented. It is intended as a time code for spacecraft and ground applications where direct code compatibility with automatic data processing equipment is of primary consideration. The principal features of this time code are: byte oriented format, selectable resolution options (from seconds to nanoseconds); and long ambiguity period. The time code is compatible with the new data handling and management concepts such as the NASA End-to-End Data System and the Telemetry Data Packetization format.

Chi, A. R.↗
NASA NTRS1979

Solar power satellite system definition study. Volume 3: Operations and systems synthesis, phase 2

The results of the operations analyses are reported. Some of these analyses examined operations aspects of space vehicle in-space maintenance. Many of the analyses explored in great depth operations concerned the LEO Base cargo handling operations. Personnel transportation operations and cargo packaging were also analyzed. These operations analyses were performed to define the operational requirements for all of the SPS system elements so that equipment and facilities could be synthesized, and to make estimates of the manpower requirements. An overall, integrated, end-to-end description of the SPS operations is presented. The detailed operations analyses, upon which this integrated description was based, are included.

Source record↗
NASA NTRS1980

Satellite power system (SPS) concept definition study. Volume 3: Experimental verification definition

An evolutionary Satellite Power Systems development plan was prepared. Planning analysis was directed toward the evolution of a scenario that met the stated objectives, was technically possible and economically attractive, and took into account constraining considerations, such as requirements for very large scale end-to-end demonstration in a compressed time frame, the relative cost/technical merits of ground testing versus space testing, and the need for large mass flow capability to low Earth orbit and geosynchronous orbit at reasonable cost per pound.

Hanley, G. M.↗
NASA NTRS1979

User-oriented end-to-end transport protocols for the real-time distribution of telemetry data from NASA spacecraft

A set of standard telemetry protocols for downlink data flow facilitating the end-to-end transport of instrument data from the spacecraft to the user in real time is proposed. The direct switching of data by autonomous message 'packets' that are assembled by the source instrument on the spacecraft is discussed. The data system consists thus of a format on a message rather than word basis, and such packet telemetry would include standardized protocol headers. Standards are being developed within the NASA End-to-End Data System (NEEDS) program for the source packet and transport frame protocols. The source packet protocol contains identification of both the sequence number of the packet as it is generated by the source and the total length of the packet, while the transport frame protocol includes a sequence count defining the serial number of the frame as it is generated by the spacecraft data system, and a field specifying any 'options' selected in the format of the frame itself.

Hooke, A. J.↗