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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

A comparison of Frequency Domain Multiple Access (FDMA) and Time Domain Multiple Access (TDMA) approaches to satellite service for low data rate Earth stations

A technological and economic assessment is made of providing low data rate service to small earth stations by satellite at Ka-band. Various Frequency Domain Multiple Access (FDMA) and Time Domain Multiple Access (TDMA) scenarios are examined and compared on the basis of cost to the end user. Very small stations (1 to 2 meters in diameter) are found not to be viable alternatives to available terrestrial services. However, medium size (3 to 5 meters) earth stations appear to be very competitive if a minimum throughput of about 1.5 Mbs is maintained. This constrains the use of such terminals to large users and shared use by smaller users. No advantage was found to the use of FDMA. TDMA had a slight advantage from a total system viewpoint and a very significant advantage in the space segment (about 1/3 the required payload weight for an equivalent capacity).

Stevens, G.↗
NASA NTRS1983

Space stations - A historical perspective

This paper discusses the historical evolution of the space station concept, with particular attention to NASA plans in the 1960-1980 period. Emphasis is given to the changing justification presented for station development during that period and to the political context within which station proposals were evaluated.

Logsdon, J. M.↗
NASA NTRS1983

The importance of the space station as an element of the total Space System architecture

The paper describes the role of the Space Station in the ensemble of the space-based infrastructure necessary for achieving permanent manned presence in space. The major elements of the architecture are identified, functionally interrelated and discussed in terms of their evolutionary development as an extension of current STS capabilities. It is shown that they require a logical succession of flight R&D experiments and demonstrations using the Space Shuttle and the Space Station as test beds. The paper describes the interrelationships between the Space Station and the various major infrastructure elements and shows that the latter are indispensable for full operational utilization of the former. Only the total ensemble of the architecture provide all the necessary prerequisites for permanent manned presence in space.

Bekey, I.↗
NASA NTRS1983

Planning for long term control of Space Station

The National Aeronautics and Space Administration (NASA) is conducting conceptual studies concerning the development of a future U.S. Space Station. The Space Station navigation, guidance, and control functions must be performed over the projected long lifetime of the station. After examining the pertinent history of U.S. spacecraft, this paper examines how these long-term operations can be achieved, settling on autonomous operations as a desirable goal. The paper concludes with a recommended development approach.

Buchanan, H.↗
NASA NTRS1983

Orbit keeping attitude control for space station

It is pointed out that on-orbit configuration variability is expected to be a characteristic of a space station. The implementation of such a chracteristic will present reboost and thruster control system designers with a number of new challenges. The primary requirement for the space station orbit reboost (or orbit keeping) system is to ensure system viability for extended duration and prevent an uncontrolled reentry as with Skylab. For a station in a low earth orbit, earodynamic drag will be sufficient to cause relatively quick orbit altitude decay. A propulsion system is, therefore, needed to counteract the aerodynamic drag forces and to boost the vehicle to the desired orbit altitudes. A description is given of a typical reboost operational procedure and propellant requirements. Attention is given to thruster control systems, and aspects of reboost guidance.

Barrows, D.↗
NASA NTRS1983

Space station needs, attributes and architectural options study. Volume 3: Requirements

A typical system specification format is presented and requirements are compiled. A Program Specification Tree is shown showing a high inclination space station and a low inclination space station with their typical element breakdown, also represented along the top blocks are the interfaces with other systems. The specification format is directed at the Low Inclination space station.

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NASA NTRS1983

Space station needs, attributes and architectural options. Part 1: Summary

Candidate missions for the space station were subjected to an evaluation/filtering process which included the application of budgetary constraints and performance of benefits analysis. Results show that the initial space station should be manned, placed in a 28.5 deg orbit, and provide capabilities which include a space test facility, satellite service, a transport harbor, and an observatory. A space industrial park may be added once further development effort validates the cost and expanding commercial market for space-processed material. Using the space station as a national space test facility can enhance national security, as well as commercial and scientific interests alike. The potential accrued gross mission model benefit derived from these capabilities is $5.9B without the industrial park, and $9.3B with it. Other benefits include the lowering of acquisition costs for NASA and DoD space assets and a basis for broadening international participation.

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NASA NTRS1983

Space Station needs, attributes and architectural options. Volume 2, book 1, part 1: Mission requirements

The baseline mission model used to develop the space station mission-related requirements is described as well as the 90 civil missions that were evaluated, (including the 62 missions that formed the baseline model). Mission-related requirements for the space station baseline are defined and related to space station architectural development. Mission-related sensitivity analyses are discussed.

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NASA NTRS1984

Definition of technology development missions for early space stations. Large space structures, phase 2, midterm review

The large space structures technology development missions to be performed on an early manned space station was studied and defined and the resources needed and the design implications to an early space station to carry out these large space structures technology development missions were determined. Emphasis is being placed on more detail in mission designs and space station resource requirements.

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NASA NTRS1982

Space station needs, attributes and architectural options study. Briefing material, mid-term review

User mission requirements and their relationship to the current space transportation system are examined as a means of assuring the infusion of corporate ideas and knowledge in the space station program. Specific tasks include developing strategies to develop user consistency; determine DOD implication and requirements; and foster industry involvement in the space station. Mission alternatives; accrued benefits; program options; system attributes and characteristics; and a recommended plan for space station evolution are covered.

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NASA NTRS1984

Space Station commercial user development

The commercial utilization of the space station is investigated. The interest of nonaerospace firms in the use of the space station is determined. The user requirements are compared to the space station's capabilities and a feasibility analysis of a commercial firm acting as an intermediary between NASA and the private sector to reduce costs is presented.

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NASA NTRS1983

Study of robotics systems applications to the space station program

Applications of robotics systems to potential uses of the Space Station as an assembly facility, and secondarily as a servicing facility, are considered. A typical robotics system mission is described along with the pertinent application guidelines and Space Station environmental assumptions utilized in developing the robotic task scenarios. A functional description of a supervised dual-robot space structure construction system is given, and four key areas of robotic technology are defined, described, and assessed. Alternate technologies for implementing the more routine space technology support subsystems that will be required to support the Space Station robotic systems in assembly and servicing tasks are briefly discussed. The environmental conditions impacting on the robotic configuration design and operation are reviewed.

Fox, J. C.↗
NASA NTRS1984

Structural performance of orthogonal tetrahedral truss Space-Station configurations

Two 150 kW space station configurations constructed with the orthogonal tetrahedral truss concept are described. One space station consists of a large central platform and two rotating solar wing arrays and the other consists of a long central keel with two rotating arrays. The dynamic characteristics of each configuration are obtained with and without nonstructural components present. The variation in frequencies and mass moments of inertia due to rotation of the two solar wing arrays are given for the long keel space station configuration. The structural performance of the solar wing array is assessed for cases where individual critical struts fail in the array support truss.

Dorsey, J. T.↗
NASA NTRS1983

Proceedings of the Flat-Plate Solar Array Project Research Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Stations

The Flat Plate Solar Array Project, focuses on advancing technologies relevant to the design and construction of megawatt level central station systems. Photovoltaic modules and arrays for flat plate central station or other large scale electric power production facilities require the establishment of a technical base that resolves design issues and results in practical and cost effective configurations. Design, qualification and maintenance issues related to central station arrays derived from the engineering and operating experiences of early applications and parallel laboratory reserch activities are investigated. Technical issues are examined from the viewpoint of the utility engineer, architect/engineer and laboratory researcher. Topics on optimum source circuit designs, module insulation design for high system voltages, array safety, structural interface design, measurements, and array operation and maintenance are discussed.

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NASA NTRS1984

A review of micrometeoroid flux measurements and models for low orbital altitudes of the Space Station

A review of meteoroid flux measurements and models for low orbital altitudes of the Space Station has been made in order to provide information that may be useful in design studies and laboratory hypervelocity impact tests which simulate micrometeoroids in space for design of the main wall of the Space Station. This report deals with the meteoroid flux mass model, the defocusing and shielding factors that affect the model, the probability of meteoroid penetration of the main wall of a Space Station. Whipple (1947) suggested a meteoroid bumper, a thin shield around the spacecraft at some distance from the wall, as an effective device for reducing penetration, which has been discussed in this report. The equations of the probability of meteoroid penetration, the average annual cumulative total flux, and the equations for the thickness of the main wall and the bumper are presented in this report.

Susko, M.↗
NASA NTRS1984

Photovoltaic power system for satellite Earth stations in remote areas: Project status and design description

A photovoltaic power system which will be installed at a remote location in Indonesia to provide power for a satellite Earth station and a classroom for video and audio teleconferences are described. The Earth station may also provide telephone service to a nearby village. The use of satellite communications for development assistance applications and the suitability of a hybrid photovoltaic engine generator power system for remote satellite Earth stations are demonstrated. The Indonesian rural satellite project is discussed and the photovoltaic power system is described.

Delombard, R.↗