208,202 research outputs found
Development of an Orbital Receiver for Low-Frequency Radio Energy from the Planet Jupiter Final Report
Development of radio receiver for Pioneer F/G Asteroid-Jupiter spacecraf
Space processing applications payload equipment study. Volume 2B: Payload interface analysis (power/thermal/electromagnetic compatibility)
As a part of the task of performing preliminary engineering analysis of modular payload subelement/host vehicle interfaces, a subsystem interface analysis was performed to establish the integrity of the modular approach to the equipment design and integration. Salient areas that were selected for analysis were power and power conditioning, heat rejection and electromagnetic capability (EMC). The equipment and load profiles for twelve representative experiments were identified. Two of the twelve experiments were chosen as being representative of the group and have been described in greater detail to illustrate the evaluations used in the analysis. The shuttle orbiter will provide electrical power from its three fuel cells in support of the orbiter and the Spacelab operations. One of the three shuttle orbiter fuel cells will be dedicated to the Spacelab electrical power requirements during normal shuttle operation. This power supplies the Spacelab subsystems and the excess will be available to the payload. The current Spacelab sybsystem requirements result in a payload allocation of 4.0 to 4.8 kW average (24 hour/day) and 9.0 kW peak for 15 minutes
Space processing applications payload equipment study. Volume 2D: SPA supplemental power and heat rejection kit
The design and application of a supplementary power and heat rejection kit for the Spacelab are discussed. Two subsystems of electric power and thermal control were analyzed to define the requirements for the power and heat rejection kit (PHRK). Twelve exemplary experiments were defined and power timelines were developed. From these timeline, the experiment requirements for sustained power, peak power, and energy were determined. The electrical power subsystem of the PHRK will consist of two fuel cells, oxygen and hydrogen reactant tank assemblies, water storage tanks, plumbing, cabling, and inverters to convert the nominal 28 volt dc fuel cell output to ac power
Thermal insulation protection means
A system for providing thermal insulation for portions of a spacecraft which do not exceed 900 F during ascent or reentry relative to the earth's atmosphere is described. The thermal insulation is formed of relatively large flexible sheets of needled Nomex felt having a flexible waterproof coating. The thickness of the felt is sized to protect against projected temperatures and is attached to the structure by a resin adhesive. Vent holes in the sheets allow ventilation while maintaining waterproofing. The system is heat treated to provide thermal stability
No evidence of dark matter in the solar neighborhood
We measured the surface mass density of the Galactic disk at the solar
position, up to 4 kpc from the plane,by means of the kinematics of ~400 thick
disk stars. The results match the expectations for the visible mass only, and
no dark matter is detected in the volume under analysis. The current models of
dark matter halo are excluded with a significance higher than 5sigma, unless a
highly prolate halo is assumed, very atypical in cold dark matter simulations.
The resulting lack of dark matter at the solar position challenges the current
models.Comment: Proceeding of the first binational Sochias-AAA meeting, held in San
Juan, Argentin
Theoretical Interpretation of the Measurements of the Secondary Eclipses of TrES-1 and HD209458b
We calculate the planet-star flux-density ratios as a function of wavelength
from 0.5 microns to 25 microns for the transiting extrasolar giant planets
TrES-1 and HD209458b and compare them with the recent Spitzer/IRAC-MIPS
secondary eclipse data in the 4.5, 8.0, and 24 micron bands. With only three
data points and generic calibration issues, detailed conclusions are difficult,
but inferences regarding atmospheric composition, temperature, and global
circulation can be made. Our models reproduce the observations reasonably well,
but not perfectly, and we speculate on the theoretical consequences of
variations around our baseline models. One preliminary conclusion is that we
may be seeing in the data indications that the day side of a close-in
extrasolar giant planet is brighter in the mid-infrared than its night side,
unlike Jupiter and Saturn. This correspondence will be further tested when the
data anticipated in other Spitzer bands are acquired, and we make predictions
for what those data may show.Comment: 15 pages, including 3 color figures, submitted to the Astrophysical
Journa
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