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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Solar events and their influence on the interplanetary medium

Aspects of a workshop on Solar events and their influence on the interplanetary medium, held in September 1986, are reviewed, the goal of which was to foster interactions among colleagues, leading to an improved understanding of the unified relationship between solar events and interplanetary disturbances. The workshop consisted of three working groups: (1) flares, eruptives, and other near-Sun activity; (2) coronal mass ejections; and (3) interplanetary events. Each group discussed topics distributed in advance. The flares-eruptives group members agreed that pre-event energy is stored in stressed/sheared magnetic fields, but could not agree that flares and other eruptive events (e.g., eruptive solar prominences) are aspects of the same physical phenomenon. In the coronal mass ejection group, general agreement was reached on the presence of prominences in CMEs, and that they have a significant three-dimensional structure. Some topics identified for further research were the aftermath of CMEs (streamer deflections, transient coronal holes, possible disconnections), identification of the leading edge of CMEs, and studies of the range and prevalence of CME mass sizes and energies.

Joselyn, Joann↗
NASA NTRS1987

Large-scale interaction of the solar wind with comets Halley and Giacobini-Zinner

In-situ measurements of comets Halley and Giacobini-Zinner have confirmed the accepted basic physics of comet/solar wind interaction. The solar wind magnetic field is captured by the comet through the mechanism of field-line loading by cometary ions and the field lines drape around the cometary ionosphere. With this basic model in hand, the large-scale structure of the plasma tail as revealed by submissions to the Large Scale Phenomena Network of the International Halley Watch is reviewed. The turn-on and turn-off of plasma activity seem consistent with theory. Some 16 obvious disconnection events (DEs) have been recorded. Preliminary results showed agreement with the sector-boundary model; a detailed analysis of all DEs will be required in order to make a definitive statement. A study of plasma activity around the time of the VEGA encounters provides strong support for the sector-boundary model and illustrates once again the power of simultaneous remote and in-situ measurements.

Brandt, John C.↗
NASA NTRS1987

Servicer system demonstration plan and capability development

An orbital maneuvering vehicle (OMV) front end kit is defined which is capable of performing in-situ fluid resupply and modular maintenance of free flying spacecraft based on the integrated orbital servicing system (IOSS) concept. The compatibility of the IOSS to perform gas and fluid umbilical connect and disconnect functions utilizing connect systems currently available or in development is addressed. A series of tasks involving on-orbit servicing and the engineering test unit (ETU) of the on-orbit service were studied. The objective is the advancement of orbital servicing by expanding the Spacecraft Servicing Demonstration Plan (SSDP) to include detail demonstration planning using the Multimission Modular Spacecraft (MMS) and upgrading the ETU control.

Source record↗
NASA NTRS1987

Ames Research Center cryogenics program

Viewgraphs describe the Ames Research Center's cryogenics program. Diagrams are given of a fluid management system, a centrifugal pump, a flow meter, a liquid helium test facility, an extra-vehicular activity coupler concept, a dewar support with passive orbital disconnect, a pulse tube refrigerator, a dilution refrigerator, and an adiabatic demagnetization cooler.

Kittel, Peter↗
NASA NTRS1988

Modification and development of the external tank hydrogen vent umbilical system for the space shuttle vehicle

The design and development of a new T-O lock and secondary release mechanism which is being introduced to the ET Hydrogen Vent Umbilical System for the next launch of the Space Shuttle Vehicle is described. Critical analysis of the system in early 1986 indicated the need for an improvement in the secondary release system. The new T-O lock increases the clearance with the vehicle during secondary disconnect and is described.

Tatem, Bemis C., Jr.↗
NASA NTRS1987

Modeling and stability analysis for the upper atmosphere research satellite auxiliary array switch component

A feedback control system, called an auxiliary array switch, was designed to connect or disconnect auxiliary solar panel segments from a spacecraft electrical bus to meet fluctuating demand for power. A simulation of the control system was used to carry out a number of design and analysis tasks that could not economically be performed with a breadboard of the hardware. These tasks included: (1) the diagnosis of a stability problem, (2) identification of parameters to which the performance of the control system was particularly sensitive, (3) verification that the response of the control system to anticipated fluctuations in the electrical load of the spacecraft was satisfactory, and (4) specification of limitations on the frequency and amplitude of the load fluctuations.

Wolfgang, R.↗
NASA NTRS1987

Preliminary investigation of inertia friction welding B2 aluminides

An attempt is made to achieve inertia friction-welding in FeAl and NiAl samples, taking into account their intermetallics' compositions, extrusion parameters, and microstructural data. The energy required for the weld is stored in a rotating flywheel mass attached to one of the two pieces to be joined; when enough energy is introduced, the flywheel is disconnected and an axial load is applied which forces the spinning piece against the stationary one, converting the energy into heat by means of friction. Due to the inherent brittleness of the aluminides, a step-load program was used in which an initial, low-pressure heat buildup increased the work pieces' ductility.

Whittenberger, J. Daniel↗
NASA NTRS1987

Cometary plasma - A review

Results of spacecraft probing of Comet Halley and Comet Giacobini-Zinner are used to investigate cometary plasma processes and large-scale structure. Examples of tail phenomena are discussed, with emphasis on the observed disconnection events (DEs). The sector boundary/magnetic reconnection model for DEs of Niedner and Brandt, (1978) is shown to be consistent with the times of known DEs in Comet Halley as well as the magnetic polarity data available from interplanetary and near-earth satellites, and from solar data. Results of the present review have application to understanding of the solar-wind/comet interaction during the 1985-1986 apparition of Comet Halley.

Brandt, John C.↗
NASA NTRS1987

The nature of comets

The large-scale structure, dynamics, and chemical composition of comets are examined on the basis of preliminary ground-based and space-probe data from the Halley return of 1986. Diagrams, graphs, photographs, and false-color images are provided, and data on Comet Giacobini-Zinner are included for comparison. Features noted include solar-wind interaction with magnetic-field draping around the head region, dramatic disconnection events, an irregularly shaped monolithic primarily water-ice nucleus and a dark surface, and dust with chemical composition like that of (H, C, N, O)-enriched carbonaceous chondrites.

Brandt, J. C.↗
NASA NTRS1987

Space Station body mounted radiator design

Consideration has been given to utilizing the external area of the Space Station common modules or resource nodes to provide heat rejection. A program was undertaken to define the best body mounted radiator design, to define and build a full size test article and to conduct testing to verify performance. Trade studies were conducted and a preferred design selected. The selected design employed high performance grooved heat pipes of an off-the-shelf design. Twenty panels, each about 1.2 m wide by 5.6 m long are installed on each module rejecting a total of about 12 kW. The radiators are interfaced with the module thermal control loop by use of a refrigerant 21 loop with an on-orbit operable disconnect at each panel. A one-panel test article has been designed and is currently being fabricated. Testing is scheduled to be conducted in June of 1987.

Fleming, M. L.↗
NASA NTRS1987

Structure and dynamics of the plasma tail of comet P/Halley. I - Knot event on December 31, 1985

On the basis of about 500 photographs of comet Halley taken by many observers, Saito et al. (1986) classified the detected disturbances of the plasma tail as outstanding rays, streamer, helix, kink, arcade, and disconnection event (DE). In this paper, the interaction of the solar wind with the plasma tail of Comet P/Halley is examined by using results of observations by the Sakigake spacecraft of the December 31, 1985 event, which included various disturbances and one DE-like knot. On the basis of twenty photographs taken on December 31 by Japanese astronomers, the dynamic pressure model proposed by Saito et al. (1986) is examined, and the mechnism of the knot event that appeared in the plasma tail of the comet on December 31, is explained.

Saito, T.↗
NASA NTRS1987

Plasma structures in comets P/Halley and Giacobini-Zinner

An overview of large-scale plasma phenomena is presented based on results of spacecraft probing of comets Halley and Giacobini-Zinner and on worldwide submissions to the Large-Scale Phenomena Discipline Specialist Team of the International Halley Watch. Examples of tail phenomena and science are presented with emphasis on observed disconnection events. The archive of this material will clearly be very valuable for studying the comet/solar-wind interaction during the 1985-1986 apparition of Halley's comet.

Brandt, J. C.↗
NASA NTRS1987

Plasma and magnetic field variations in the distant magnetotail associated with near-earth substorm effects

Examination of many individual event periods in the ISEE 3 deep-tail data set has suggested that magnetospheric substorms produce a characteristic pattern of effects in the distant magnetotail. During the growth, or tail-energy-storage phase of substorms, the magnetotail appears to grow diametrically in size, often by many earth radii. Subsequently, after the substorm expansive phase onset at earth, the distant tail undergoes a sequence of plasma, field, and energetic-particle variations as large-scale plasmoids move rapidly down the tail following their disconnection from the near-earth plasma sheet. ISEE 3 data are appropriate for the study of these effects since the spacecraft remained fixed within the nominal tail location for long periods. Using newly available auroral electrojet indices (AE and AL) and Geo particle data to time substorm onsets at earth, superposed epoch analyses of ISEE 3 and near-earth data prior to, and following, substorm expansive phase onsets have been performed. These analyses quantify and extend substantially the understanding of the deep-tail pattern of response to global substorm-induced dynamical effects.

Baker, D. N.↗
NASA NTRS1988

The use of force feedback control for robotic mating of umbilical fuel lines

Control problems in developing force feedback control to use in remotely connecting, disconnecting, and reconnecting the umbilical fuel lines of the Space Shuttle Vehicle are discussed. A docking protocol is proposed, indicating the required role of force feedback. The use of active force feedback control is examined and performance requirements and experimental results are given. A single degree-of-freedom force feedback model is presented and the application of classical control compensation techniques to the force control loop to increase flexibility is considered. In addition, possible modifications to the controller and plans for future research are discussed.

Fullmer, R.↗
NASA NTRS1988

The superfluid helium on-orbit transfer (SHOOT) flight experiment

The SHOOT flight demonstration is being undertaken to verify component and system level technology necessary to resupply large superfluid helium dewars in space. The baseline configuration uses two identical 210 liter dewars connected by a transfer line which contains a quick disconnect coupling. The helium will be transferred back and forth between the dewars under various conditions of flow rate, parasitic heat load, and temperature. An astronaut Extra-vehicular Activity (EVA) is also planned to manually demate and mate the coupling. A number of components necessary for the flight are being developed. These components are described here.

Dipirro, Michael J.↗
NASA NTRS1989

High Temperature Gas-Gap Thermal Switch

Device set to allow heat to flow across gap (switch "on") or decrease rate of transfer of heat to relatively low value (switch "off"). Operates at temperatures in approximate range of 100 to 1,500 degree C. Central cylindrical object thermally connected to (or disconnected from) environment by filling gap between inner and outer sleeves of switch (or evacuating gap) to increase (or decrease) thermal conduction across gap.

Bard, Steven↗
NASA NTRS1989

Compact Right-Angle Connector

New right-angle connector between hose and "quick-disconnect" coupler smaller and simpler than its predecessor. Employs fewer parts and therefore cheaper and less likely to leak. Connector consists of only two major parts.

Barajas, Salvador L.↗
NASA NTRS1989

Inflatable-Seal Assembly For Cryogenic Fluids

Connector for cryogenic fluid lines quickly joined or separated, seals tightly, and reduces transfer of heat to fluid. Features redundant sealing rings inflated after joining so they wedge tightly against connector base, preventing leakage. Cylinder of FEP inflatable. Pair of threaded stainless-steel rings - one at each end of cylinder - secure cylinder in quick-disconnect assembly.

Buehler, Kurt↗