209 research outputs found
EPA/ECLSS consumables analyses for the Spacelab 1 flight
The results of electrical power system (EPS) and environmental control/life support system (ECLSS) consumables analyses of the Spacelab 1 mission are presented. The analyses were performed to assess the capability of the orbiter systems to support the proposed mission and to establish the various non propulsive consumables requirements. The EPS analysis was performed using the shuttle electrical power system (SEPS) analysis computer program. The ECLSS analysis was performed using the shuttle environmental consumables requirements evaluation tool (SECRET) program
Electrical-power-system data base for consumables analysis. Volume 1: Electrical equipment list, activity blocks, and time lines
A standardized data base is described which consists of a space shuttle electrical equipment list, activity blocks defining electrical equipment utilization, and activity-block time lines for specific mission analyses. Information is presented to facilitate utilization of the data base, to provide the basis for the electrical equipment utilization to enable interpretation of analyses based on the data contained herein
A spherical lamellar grating interferometer for airborne astronomical observations of far infrared objects
A lamellar grating has been developed to be used for very far infrared observations on the airborne observatory. The design characteristics and performance during laboratory testing and initial observations of Jupiter at wavelengths between 50 and 500 microns are presented
Electrical-power-system data base for consumables analysis. Volume 2: Electrical equipment utilization
A catalogue is presented of space shuttle electrical equipment as used within a standardized data base for EPS consumables analyses. The general function and expected usage of each type of electrical equipment are described, and the usage of specific equipment of each type in the performance of EPS consumables analyses is defined
EPS analysis of nominal STS-1 flight
The results of electrical power system (EPS) analysis of the planned Shuttle Transportation System Flight 1 mission are presented. The capability of the orbiter EPS to support the planned flight and to provide program tape information and supplementary data specifically requested by the flight operations directorate was assessed. The analysis was accomplished using the orbiter version of the spacecraft electrical power simulator program, operating from a modified version of orbiter electrical equipment utilization baseline revision four. The results indicate that the nominal flight, as analyzed, is within the capabilities of the orbiter power generation system, but that a brief, and minimal, current overload may exist between main distributor 1 and mid power controlled 1, and that inverter 9 may the overloaded for extended periods of time. A comparison of results with launch commit criteria also indicated that some of the presently existing launch redlines may be violated during the terminal countdown
Balanced measures, sparse domination and complexity-dependent weight classes
We study sparse domination for operators defined with respect to an atomic
filtration on a space equipped with a general measure . In the case of
Haar shifts, -boundedness is known to require a weak regularity condition,
which we prove to be sufficient to have a sparse domination-like theorem. Our
result allows us to characterize the class of weights where Haar shifts are
bounded. A surprising novelty is that said class depends on the complexity of
the Haar shift operator under consideration. Our results are qualitatively
sharp
Electrical power requirements analysis. Single failure tolerant entry
The results of an analysis of the orbiter electrical power system for the case of a single failure tolerant (SFT) entry are presented. The analysis was performed using the shuttle electrical power system analysis computer program. It was performed to permit assessment of the capability of the orbiter systems to support the proposed entry configuration and to provide the data necessary to identify potential constraints and limitations. Three contingency modes have been identified which would require an SFT entry. This analysis addresses an SFT entry resulting from the loss of two fuel cell powerplants, while on orbit. The results of the analysis indicate that, even under near optimum conditions, the fuel cell power demand will exceed the tested operating capacity of 16 kw, and that various electrical components may experience voltages below 24 VDC
A Structural Analysis of Star-Forming Region AFGL 490
We present Spitzer IRAC and MIPS observations of the star-forming region
containing intermediate-mass young stellar object (YSO) AFGL 490. We supplement
these data with near-IR 2MASS photometry and with deep SQIID observations off
the central high extinction region. We have more than doubled the known
membership of this region to 57 Class I and 303 Class II YSOs via the combined
1-24 um photometric catalog derived from these data. We construct and analyze
the minimum spanning tree of their projected positions, isolating one locally
over-dense cluster core containing 219 YSOs (60.8% of the region's members). We
find this cluster core to be larger yet less dense than similarly analyzed
clusters. Although the structure of this cluster core appears irregular, we
demonstrate that the parsec-scale surface densities of both YSOs and gas are
correlated with a power law slope of 2.8, as found for other similarly analyzed
nearby molecular clouds. We also explore the mass segregation implications of
AFGL 490's offset from the center of its core, finding that it has no apparent
preferential central position relative to the low-mass members.Comment: 44 pages, 13 figures, accepted to Ap
Gas-phase CO2 emission toward Cepheus A East: the result of shock activity?
We report the first detection of gas-phase CO2 emission in the star-forming
region Cepheus A East, obtained by spectral line mapping of the v2 bending mode
at 14.98 micron with the Infrared Spectrograph (IRS) instrument onboard the
Spitzer Space Telescope. The gaseous CO2 emission covers a region about 35'' x
25'' in extent, and results from radiative pumping by 15 micron continuum
photons emanating predominantly from the HW2 protostellar region. The gaseous
CO2 exhibits a temperature distribution ranging from 50 K to 200 K. A
correlation between the gas-phase CO2 distribution and that of H2 S(2), a
tracer of shock activity, indicates that the CO2 molecules originate in a cool
post-shock gas component associated with the outflow powered by HW2. The
presence of CO2 ice absorption features at 15.20 micron toward this region and
the lack of correlation between the IR continuum emission and the CO2 gas
emission distribution further suggest that the gaseous CO2 molecules are mainly
sputtered off grain mantles -- by the passage of slow non-dissociative shocks
with velocities of 15-30 km/s -- rather than sublimated through grain heating.Comment: 11 pages, 6 figures, accepted for publication in ApJ
The Initial Configuration of Young Stellar Clusters: A K-band Number Counts Analysis of the Surface Density of Stars
We present an analysis of K-band stellar distributions for the young stellar
clusters GGD 12-15, IRAS 20050+2720, and NGC 7129. We find that the two deeply
embedded clusters, GGD 12-15 and IRAS 20050+2720, are not azimuthally symmetric
and show a high degree of structure which traces filamentary structure observed
in 850 micron emission maps. In contrast, the NGC 7129 cluster is circularly
symmetric, less dense, and anti-correlated to 850 micron emission, suggesting
recent gas expulsion and dynamical expansion have occured. We estimate stellar
volume densities from nearest neighbor distances, and discuss the impact of
these densities on the evolution of circumstellar disks and protostellar
envelopes in these regions.Comment: 44 pages, 26 figures, Accepted to ApJ. Changes include extinction
mapping, Monte Carlo field star modeling, and Nyquist sampled azimuthal
stellar distributions. A version with full resolution figures is available at
http://astro.pas.rochester.edu/~rguter/preprints/gutermuth_sd.tar.g
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