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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 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Space platforms for NASA - Opportunity or pitfall

The paper describes NASA efforts to determine if platform to pool payload services are cost effective. It is shown that the platform concept originated from the short Shuttle life on orbit, the Shuttle capability to assemble aggregating structures, and the belief that economics might be obtained from shared services and repair. In addition, about eighty payloads in NASAs future were identified for consideration. Attention is given to platform configurations produced by contractor and in house studies, noting that comparative cost studies are currently being done.

Cuneo, W. J., Jr.↗
NASA NTRS1980

Developing the concept of a geostationary platform

A geostationary platform concept with a proliferation of low-cost earth stations is discussed. Candidate platform concepts, servicing, life, and Orbital Transfer Vehicle (OTV) options are considered. A Life Cycle Costing model is used to select the minimum cost concept meeting program criteria. It is concluded that the geostationary platform concept is a practical and economical approach to providing expanding communication services within the limitations imposed by the available frequency spectrum and orbital arc.

Carey, W. T.↗
NASA NTRS1980

Structural sizing considerations for large space platforms

Structural optimization studies are made using mathematical programming techniques to examine minimum mass structural proportions of deployable and erectable tetrahedral truss platforms subject to the integrated effects of practical design requirements. Considerations integrated into the optimization process are: 1) lowest natural frequencies of the platform and individual platform components (struts); 2) packaging constraints imposed by the Shuttle cargo bay capacity; 3) initial curvature of the struts; 4) column buckling of the struts due to gravity gradient, orbital transfer, strut length tolerance, or design loads; and 5) practical lower limits for strut diameter and wall thickness. Ultra-low mass designs are shown to be possible with strut proportions much more slender than those conventionally used for earthbound application.

Heard, W. L., Jr.↗
NASA NTRS1980

Geostationary platform systems concepts definition study. Volume 2: Technical, book 3

The supporting research and technology, and space demonstrations required to support the 1990s operational geostationary platforms are identified. Also the requirements on and interfaces with the Space Transportation System hardware elements supporting the geostationary platform program, including the shuttle, orbital transfer vehicles, teleoperator, etc., are investigated to provide integrated support requirements. Finally, a preliminary evaluation of the practicability and capabilities of an experimental platform from the standpoint of technology, schedule, and cost is given.

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NASA NTRS1981

Space platform reference mission studies overview

The design requirements for three major space platform systems are identified. The three were the Science and Applications Space Platform (SASP), the Geostationary Platform (GSP), and the Satellite Power System (SPS). Because the SASP and GSP were assumed to require no advanced technology for their development an advanced version of each was selected on which to base the design requirements. The SPS represented the opposite development state hence a nearer term test article was selected on which to base the requirements. The development period for these missions is estimated.

Harrison, J. K.↗
NASA NTRS1981

Space platform advanced technology study

Current and past space platform and power module studies were utilized to point the way to areas of development for mechanical devices that will be required for the ultimate implementation of a platform erected and serviced by the Shuttle/Orbiter. The study was performed in accordance with a study plan which included: a review of space platform technology; orbiter berthing system requirements; berthing latch interface requirements, design, and model fabrication; berthing umbilical interface requirements and design; adaptive end effector design and model fabrication; and adaptive end effector requirements.

Burns, G.↗
NASA NTRS1981

Science and Applications Space Platforms - A NASA overview

An overview of past, present, and future activities relating to space platforms is presented, with emphasis placed on implementation of the initial platform. It is noted that the challenge at present is to define an initial system that can accommodate high priority science, that possesses the capability of doing multi-discipline science, and that demonstrates on-orbit servicing and payload exchange through use of the Shuttle. The evolution of the Science and Applications Space Platform (SASP), which will provide significantly more time on-orbit for instrument operations without increasing Space Shuttle orbiter time on-orbit, is traced. The importance of completing all required activities to support a new start for the SASP in fiscal year 1983 is stressed. While the initial SASP will support only a limited set of investigations, the program will evolve by replication, upgrading, or the development of new systems to support a broader and generally more demanding set of system requirements.

De Sanctis, C. E.↗
NASA NTRS1981

A concept for high speed assembly of erectable space platforms

A simple, fully automatic assembler associated with the on-orbit assembly of tetrahedral truss platforms erected of graphite epoxy tapered columns is described. The assembler, which can operate either as a free flyer or attached to the Orbiter, is capable of constructing a platform from a full load of truss columns and node joints in 36 hours. The geometry of this electrically-driven machine is based on a compound parallelogram system which permits backward as well as lateral translations. Concepts have been developed for half-column assembly as well as for column and node joint insertion into the platform.

Cohan, H.↗
NASA NTRS1981

Command profile for Galileo scan platform control

A recursive command profile is developed for the control of a two-degree-of-freedom scan platform mounted on a flexible structure. Perfect sensors and actuators are assumed for development and testing, and structural vibrations are minimized by actuator torque commands following a smooth torque-time profile. The integral of the smooth torque profile, the rate profile, is recursively generated by a piecewise constant second derivation, and the torque applied by the closk actuator is divided into three components. Results show that the smooth platform motion in response to the command profiles is what the Galileo control systems needs to avoid stator structural vibrations. Position, rate and acceleration profiles are also presented, and the resulting motion of the scan platform in response to command profiles is illustrated.

Man, G. K.↗
NASA NTRS1981

Geostationary multipurpose platforms

In addition to the advantages generally associated with orbital platforms, such as improved reliability, economies of scale, simple connectivity of elements, reduced tracking demands and the restraint of orbital object population growth, geostationary platforms yield: (1) continuous access by fixed ground antennas for communications services; (2) continuous monitoring of phenomena over chosen regions of the earth's surface; (3) a preferred location for many solar-terrestrial physics experiments. The geostationary platform also offers a low-risk and economical solution to the impending saturation of the orbital arc/frequency spectrum, maximizing the capacity of individual slots and increasing the utility of the entire arc. It also allows the use of many small, simple and inexpensive earth stations through complexity inversion and high power per beam. Block diagram and operational flowcharts are provided.

Bekey, I.↗
NASA NTRS1982

Control system design for the large space systems technology reference platform

Structural models and classical frequency domain control system designs were developed for the large space systems technology (LSST) reference platform which consists of a central bus structure, solar panels, and platform arms on which a variety of experiments may be mounted. It is shown that operation of multiple independently articulated payloads on a single platform presents major problems when subarc second pointing stability is required. Experiment compatibility will be an important operational consideration for systems of this type.

Edmunds, R. S.↗
NASA NTRS1982

Space platforms and meteorological applications

An overview of past, current, and future space platform activities, with emphasis on implementation of the initial space platform is presented. Utilization of the space platform for meteorological purposes is examined and shown to be practical for both research and operational payloads.

Mitchell, K. L.↗
NASA NTRS1982

An experimental geostationary platform - A step toward the 1990's

NASA studies on geostationary platforms are reviewed. Traffic models for geostationary missions through the year 2000 are presented, and the benefits of platforms are shown, as compared with accomplishing the same missions on specialized satellites. These benefits are illustrated by a case study (involving Leasat) demonstrating that substantial cost savings can result because of economies of scale. Technologies in need of development and demonstration are identified, and attention is given to the potential NASA Experimental Geostationary Platform.

Carey, W. T., Jr.↗
NASA NTRS1982

The design of the Galileo scan platform control

The design of the scan platform control for the Galileo spacecraft is described. Emphasis is given to the inertial pointing of the scan platform when the spacecraft is in the dual-spin configuration. The various methods of operation used in Galileo scan pointing are outlined. Important design considerations, such as spacecraft flexibility and the separation of the actuator and sensor by a flexible structure, are discussed. An explanation is given of the pointing requirements imposed on the scan platform control. Also given is a high level description of the relevant scan pointing algorithms. The performance of the design is demonstrated by means of a sample slew test case. The simulation program used in the test includes models of the flexibility of the stator structure, the friction in the clock and cone actuators, the gyro sensor characteristics, and the system time delays.

Chodas, J. L.↗
NASA NTRS1984

Unmanned Instrument Platform for Undersea Exploration

Instruments accommodated on moving underwater platform. Towable underwater platform 3.2 meters long, 1.2 meters wide, 1.4 meters high and has mass of about 1,250 kilogram. Platform remotely operated and unmanned. Serves as test bed for development of ocean-measuring instruments and sonars at depths to 20,000 feet.

Paine, G.↗
NASA NTRS1983

Space platforms

The expanded scientific capabilities available by interfacing an orbital, free-flying experiments platform with Shuttle tending are outlined. The platform would be lifted to orbit by the Shuttle, and modularly increased in size on subsequent flights. Science packages could be left on the 26,000 lb space platform for up to six months. Component sections would include electrical and thermal control systems, berthing ports for payloads and an Orbiter, and an attitude control, communications, and data handling subsection. A 12 kW solar array would furnish power, and interconnect with Spacelab would further enhance the operations range. All berthed science packages would have individual pointing ability and grapples for the Orbiter RMS. Eventual evolution to include facilities for a human crew and a 25 kW solar array is projected.

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