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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 397 records · Page 22
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NASA NTRS1983

Tape/head interface study

Existing high energy tapes, high track density heads, and transport guidance techniques were evaluated and characterized to enable these technologies to be employed in future spacecraft recorders with high confidence. The results of these study efforts demonstrated tracking accuracy tape and head density that will support spacecraft recorders with data rates of a minimum of 150 Mbps and storage capacities ranging from 10 to the 10th to 10 to the 11th bits. Seven high energy tapes of either .25 in width, 1.00 in width, or both, were tested. All tapes were tested at the same speed (30 ips) and the same packing density (33 KBI). The performance of all 1 in tapes was considered superior.

Source record↗
NASA NTRS1982

The far-infrared disk of M51

Far-infrared maps and multifrequency photometry are presented for M51 and its companion galaxy NGC 5195. Dust reradiates about half the starlight of the M51 + NGC 5195 system to produce the observed far-infrared (80-200 microns) luminosity of 3 x 10 to the 10th solar luminosities. Observed with 49-arcsec resolution and covering 37 arcmin-squared, the maps show that roughly 70% of this luminosity is produced by the 5 arcmin (approximately 15 kpc) wide far-infrared disk of M51. Comparable luminosities emitted from the central regions (diameters = 49 arcsec or 2.3 kpc) of M51 and NGC 5195 contribute the remaining 30% (approximately 1 x 10 to the 10th solar luminosities). The photometry reveals a difference in energetics at the galactic scale; dust producing the central luminosity of NGC 5195 classified as Ip-Ep, Irr II or SBa(r) is much less abundant and considerably warmer than the approximately 20 K dust producing the central luminosity of M51 (Sc I). Far-infrared properties are given for several galactic scale complexes of star formation in M51. Relationships are discussed for selected maps of optical starlight and emissions from these components of M51's interstellar medium: dust grains, CO molecules, hydrogen atoms, electrons, and H II regions.

Smith, J.↗
NASA NTRS1984

Outer satellite atmospheres: Their extended nature and planetary interactions

Model calculations for the brightness of the sodium cloud in Region A were performed to clarify the role played by the plasma torus sink in producing the east-west intensity asymmetry observed in the sodium D-lines. It was determined that the east-west electric field, proposed by Barbosa and Kievelson (1983) and Ip and Goertz (1983) to explain the dawn-dusk asymmetry in the torus ion emissions measured by the Voyager UVS instrument, could also produce the east-west sodium intensity asymmetry discovered earlier by Bergstralh et al. (1975, 1977). Model results for the directional features of the sodium cloud are also reported. The completion of the development of the Io potassium cloud model, progress in improving the Titan hydrogen torus model, and efforts in developing our model for hydrogen cometary atmospheres are also discussed.

Smyth, W. H.↗
NASA NTRS1984

The solar optical telescope

This paper describes NASA's Solar Optical Telescope (SOT), which is designed to measure the density temperature, magnetic fields, and the nonthermal velocity fields of solar features on a scale at which the basic physical processes are occurring. A series of 7- to 14-day missions carrying a 1.3-meter solar-observing telescope that has a spatial resolution only slightly larger than the photon mean-free-path of about 80 km will be flown as a Spacelab-attached payload aboard the Space Transportation System (STS) in mid-1990. The telescope (Fig. 1) will be built and integrated by the Perkin-Elmer Corporation and is managed by NASA's Goddard Space Flight Center. Coarse pointing to the sun is provided by the Spacelab instrument pointing system (IPS), whereas fine pointing is provided by the Observatory pointing and control system. The science instruments for the first mission, the photometric filtergraph and the coordinated filtergraph/spectrograph, that are integrated into a combined instrument package are also described.

Hogan, G. D.↗
NASA NTRS1983

The effects of hypergravity on the rate of antibody formation in the rat

This experiment was designed to measure the immune response in acutely stressed and chronically centrifuged hyper-G-adapted male rats. Rats were exposed to 2.1 and 3.1 G. Acutely stressed animals were injected with sheep red blood cells (SRBC) on the day of inital exposure to hyper-G, and were chronically centrifuged for 10 to 15 days after immunization. Hyper-G-adapted rats were chronically centrifuged for 28 days prior to antigen injection and for 21 days after injection. Booster injections were given and serum samples taken at intervals from 3 to 9 days after the initial and booster injections. Antigen dose, injected ip, ranged between 1.35 x 10 to the 6th and 1.38 x 10 to the 9th SRBC/100 g. body weight. Pair-fed and ad libitum fed noncentrifuged controls were used. No significant differences in anti-SRBC antibody titers were found between centrifuged and control animals, although there were some changes in WBC counts and a significant increase in adrenal-gland size in acutely stressed animals.

Scibetta, S. M.↗
NASA NTRS1984

Type II solar radio bursts, interplanetary shocks, and energetic particle events

Using the ISEE-3 radio astronomy experiment data 37 interplanetary (IP) type II bursts have been identified in the period September 1978 to December 1981. These events and the associated phenomena are listed. The events are preceded by intense, soft X ray events with long decay times (LDEs) and type II and/or type IV bursts at meter wavelengths. The meter wavelength type II bursts are usually intense and exhibit herringbone structure. The extension of the herringbone structure into the kilometer wavelength range results in the occurrence of a shock accelerated (SA) event. The majority of the interplanetary type II bursts are associated with energetic particle events. These results support other studies awhich indicate that energetic solar particles detected at 1 A.U. are generated by shock acceleration. From a preliminary analysis of the available data there appears to be a high correlation with white light coronal transients.

Cane, H. V.↗
NASA NTRS1984

Major element chemical compositions of chondrules in unequilibrated chondrites

The chemical compositions (except for metals and sulfides in chondrules) of more than 500 chondrules from unequilibrated E, H, L, LL, and C chondrites were measured using a broad beam of an electron-probe microanalyzer. The compositions of chondrules can be represented by various mixtures of normative compositions of olivine, low-Ca pyroxene, plagioclase, and high-Ca pyroxene with minor amounts of spinel, feldspathoid, SiO2-minerals, etc., indicating that the chondrule precursor materials consisted of aggregates of these minerals. The Al, Na, and K contents of most chondrules reflect the compositions of the ternary feldspar (An-Ab-Kf) of the chondrule precursor materials, and chemical types of chondrules (KF, SP, IP, and CP) are defined on the basis of the atomic proportion of Al, Na, and K.

Ikeda, Y.↗
NASA NTRS1984

Arguments for fundamental emission by the parametric process L yields T + S in interplanetary type III bursts

Observations of low frequency ion acoustic-like waves associated with Langmuir waves present during interplanetary Type 3 bursts are used to study plasma emission mechanisms and wave processes involving ion acoustic waves. It is shown that the observed wave frequency characteristics are consistent with the processes L yields T + S (where L = Langmuir waves, T = electromagnetic waves, S = ion acoustic waves) and L yields L' + S proceeding. The usual incoherent (random phase) version of the process L yields T + S cannot explain the observed wave production time scale. The clumpy nature of the observed Langmuir waves is vital to the theory of IP Type 3 bursts. The incoherent process L yields T + S may encounter difficulties explaining the observed Type 3 brightness temperatures when Langmuir wave clumps are incorporated into the theory. The parametric process L yields T + S may be the important emission process for the fundamental radiation of interplanetary Type 3 bursts.

Cairns, I. H.↗
NASA NTRS1985

A practical scheduling algorithm for Shuttle-based astronomy missions

In the Astro mission series (initial flight planned for March, 1986), the Shuttle will be used as a dedicated stellar astronomy observatory. A modified Spacelab pallet is to be used for the Astro payload, which will consist of three ultraviolet (UV) telescopes and a wide field camera mounted together on a single gimbal mount called the Inertial Pointing System (IPS). Three flights of 7-10 days duration are to be made with the same payload at intervals of 8-9 months. Previous experience has shown that changes in design requirements are inevitable, and the evolution of operational concepts will effect changes in scheduling algorithm software. For these reasons, the design goals of the Astron algorithm and its family of auxiliary software modules have been related to functional modularity, constraint flexibility, user friendliness, and 'light' input requirements. Attention is given to hardware characteristics, environmental constraints, the basic criteria function, 'Cinderella' logic, counters and constraints, and scheduling trends.

Guffin, O. T.↗
NASA NTRS1983

A multi-spacecraft study of the coronal and interplanetary transport of solar cosmic rays. I, II

The analysis and interpretation of the multiple-spacecraft observations of a collection of flare events in six energy bands between 3 and 60 MeV/nucleon are presented. The longitudinal and radial dependence of the times of maximum flux, the relative maximum fluxes, and the decay constants, are determined; and the propagation model is compared with a simplified single-spacecraft model. The analytical model developed accounts for the effects of diffusion, convection, adiabatic deceleration, and corotation. The intensity time profiles are calculated for hypothetical spacecraft spaced at 60-deg longitude intervals between -120 and 120 deg. It is concluded that the large value of k(IP) (greater than or equal to 6 x 10 to the 21st sq cm/s) indicates the nonnegligibility of focused diffusion in the interplanetary modeling of these events.

Mcguire, R. E.↗
NASA NTRS1985

Models of the Io torus

Results of calculations are given for three-dimensional models of the Io torus, to analyze the spectroscopic data reported by Morgan (1985). The calculations included variations in the torus plasma properties with longitude, latitude, and distance from Jupiter. The spectroscopic data are compared with the Oliversen's (S II) images and with the in situ measurements made by Voyager 1. The hypothesis is tested that the optical east-west variations reported in Morgan (1985) are consistent with the convective motions suggested by Barbosa and Kivelson (1983) and Ip and Goertz (1983). It is shown that the optical intensity asymmetry can be explained as a natural consequence of the suggested convective motions.

Morgan, J. S.↗
NASA NTRS1985

The influence of the energy emitted by solar flare soft X-ray bursts on the propagation of their associated interplanetary shock waves

The relationship between the thermal energy released from 29 solar flares and the propagation features of their associated interplanetary shock waves that were detected at 1 AU is investigated. The 29 interplanetary shock waves were identified unambiguously and their tracking from each solar flare was deduced by tracking their associated interplanetary type-II radio emission. The thermal energy released in the solar flares was estimated from the time-intensity profiles of 1-8 A soft X-ray bursts from each flare. A good relationship is found between the flares' thermal energy with the IP shock-waves' transient velocity and arrival time at the earth - that is, the largest flare energy released is associated with the faster shock waves. Finally, a possible scenario of formation of a shock wave during the early phase of the flare and its propagation features is discussed.

Pinter, S.↗
NASA NTRS1984

Spacelab transitioning to Space Station

The availability of Shuttle and Spacelab makes it possible to fly a new class of scientific instruments. Thus, larger and heavier instruments can be employed, while the return of instruments after a mission provides an opportunity for instrument reconditioning and improvement in preparation for the next flight. In addition, the Shuttle provides a basic pointing capability with its Reaction Control System (RCS) which adjusts the attitude of the entire Shuttle in the desired direction. As part of Spacelab, the European Space Agency (ESA) developed an Instrument Pointing System (IPS). Early mission results are discussed, taking into account the first scientific payload carried on the Shuttle (OSTA-1), the OSS-1 payload, Spacelab 1, Spacelab 2, the Astro payload, Sunlab, and OSTA-3. Future missions are also considered, giving attention to the Solar Optical Telescope (SOT), the Shuttle Infrared Telescope Facility (SIRTF), and the Pinhole Occulter Facility (POF). It is pointed out that a number of the instruments being developed can be modified for operation on the Space Station.

Benson, R. H.↗
NASA NTRS1987

Shuttle Ground Operations Efficiencies/Technologies (SGOE/T) study. Volume 3: Final presentation material

Charts used in the Final Phase 1 Oral Briefing at Kennedy Space Center on April 6, 1987, and to the Space Transportation Architecture Study (SPAS) Interim Program Review (IPS-5) held at MSFC on April 8, 1987, are contained. Topics discussed include: identification of existing or new technologies to reduce cost; management approaches; recommendations for research or development of specific technology for future use; and identification of new management techniques.

Scholz, A. L.↗
NASA NTRS1987

Stability studies of Solar Optical Telescope dynamics

The Solar Optical Telescope (SOT) is designed to operate as an attached payload mounted on the Instrument Pointing System (IPS) in the cargo bay of the Shuttle Orbiter. Pointing and control of SOT is accomplished by an active Articulated Primary Mirror (APM), an active Tertiary Mirror (TM), an elaborate set of optical sensors, electromechanical actuators and programmable controllers. The structural interactions of this complex control system are significant factors in the stability of the SOT. The preliminary stability study results of the SOT dynamical system are presented. Structural transfer functions obtained from the NASTRAN model of the structure were used. These studies apply to a single degree of freedom (elevation). Fully integrated model studies will be conducted in the future.

Gullapalli, Sarma N.↗
NASA NTRS1987

Pinhole occulter experiment

Viewgraphs and charts from a briefing summarize the accomplishments, results, conclusions, and recommendations of a feasibility study using the Pinhole Occulter Facility (POF). Accomplishments for 1986 include: (1) improved IPS Gimbal Model; (2) improved Crew Motion Disturbance Model; (3) use of existing shuttle on-orbit simulation to study the effects of orbiter attitude deadband size on POF performance; (4) increased understanding of maximum performance expected from current actuator/sensor set; (5) use of TREETOPS nonlinear time domain program to obtain system dynamics describing the complex multibody flexible structures; (6) use of HONEY-X design tool to design and evaluate multivariable compensator for stability, robustness, and performance; (7) application of state-of-the-art compensator design methodology Linear Quadratic Gaussian/Loop Transfer Recovery (LQG/LTR); and (8) examination of tolerance required on knowledge of the POF boom flexible mode frequencies to insure stability, using structure uncertainty analysis.

Ring, Jeff↗
NASA NTRS1985

High time service evaluation of thermal barrier coatings on the Rolls-Royce RB211 engine

One of the main concerns of airline operators for the use of thermal barrier coatings (TBC) in the turbine is that the coating will spall and cause a premature engine removal. Even though much cyclic data is available on TBCs, high time data is much harder and expensive to come by. The typical 150 h type test used to qualify hardware, or modifications, falls far short of the 5 to 10,000 hour experience desired. One way to obtain data demonstrating the longevity of TBCs is through a service evaluation program on a commercial engine. For a meaningful evaluation of the TBC system it must be applied to a component which operates in a typical hot end environment. In addition the component performance should not suffer if the coating is lost. For these reasons Rolls-Royce chose to coat the IP turbine nozzle guide vanes, and run these in an RB211 engine. Two ceramic top coats and several different bond coats were tested in a rainbow fashion on several engines. Three layer magnesium zirconate was used as a base line. Various yttria stabilized zirconia ceramics were used. Top MCrAlY bond coats were applied by various techniques. Some of the coated vanes have now accumulated ofer 5000 hours. The results are presented from the first sets with 2500 and 4200 hours of service respectively.

Toriz, F. Chris↗
NASA NTRS1989

The International Heliospheric Study; Proceedings of Symposium 10 of the 27th COSPAR Plenary Meeting, Espoo, Finland, July 18-29, 1988

The conference presents papers on solar phenomena, coronal mass ejections, solar wind, heliospheric magnetic field, energetic particles, cosmic rays, and interaction with the interstellar medium. Topics include the NASA heliospheric program, Alfven wave heating of the solar atmosphere in the transition region, IPS imaging of heliospheric transients, CME associated forward-reverse shock pairs, and solar wind latitude/longitude variations from interplanetary scintillations. Consideration is also given to cosmic ray gradients in the heliosphere, reconnection at the heliopause, and the interaction of the solar wind with the local interstellar medium.

Shea, M. A.↗