15,403 research outputs found
STS-31 Space Shuttle mission report
The STS-31 Space Shuttle Program Mission Report contains a summary of the vehicle subsystem activities on this thirty-fifth flight of the Space Shuttle and the tenth flight of the Orbiter Vehicle Discovery (OV-103). In addition to the Discovery vehicle, the flight vehicle consisted of an External Tank (ET) (designated as ET-34/LWT-27), three Space Shuttle main engines (SSME's) (serial numbers 2011, 2031, and 2107), and two Solid Rocket Booster (SRB) (designated as BI-037). The primary objective of the mission was to place the Hubble Space Telescope (HST) into a 330 nmi. circular orbit having an inclination of 28.45 degrees. The secondary objectives were to perform all operations necessary to support the requirements of the Protein Crystal Growth (PCG), Investigations into Polymer Membrane Processing (IPMP), Radiation Monitoring Equipment (RME), Ascent Particle Monitor (APM), IMAX Cargo Bay Camera (ICBC), Air Force Maui Optical Site Calibration Test (AMOS), IMAX Crew Compartment Camera, and Ion Arc payloads. In addition, 12 development test objectives (DTO's) and 10 detailed supplementary objectives (DSO's) were assigned to the flight. The sequence of events for this mission is shown. The significant problems that occurred in the Space Shuttle Orbiter subsystems during the mission are summarized, and the official problem tracking list is presented. In addition, each of the Space Shuttle Orbiter problems is cited in the subsystem discussion
STS-38 Space Shuttle mission report
The STS-38 Space Shuttle Program Mission Report contains a summary of the vehicle subsystem activities on this thirty-seventh flight of the Space Shuttle and the seventh flight of the Orbiter vehicle Atlantis (OV-104). In addition to the Atlantis vehicle, the flight vehicle consisted of an External Tank (ET) (designated as ET-40/LWT-33), three Space Shuttle main engines (SSME's) (serial numbers 2019, 2022, 2027), and two Solid Rocket Boosters (SRB's), designated as BI-039. The STS-38 mission was a classified Department of Defense mission, and as much, the classified portions of the mission are not presented in this report. The sequence of events for this mission is shown. The significant problems that occurred in the Space Shuttle Orbiter subsystem during the mission are summarized and the official problem tracking list is presented. In addition, each Space Shuttle Orbiter problem is cited in the subsystem discussion
STS-36 Space Shuttle mission report
The STS-36 Space Shuttle Program Mission Report contains a summary of the vehicle subsystem activities on this thirty-fourth flight of the Space Shuttle and the sixth flight of the OV-104 Orbiter vehicle, Atlantis. In addition to the Atlantis vehicle, the flight vehicle consisted of an External Tank (ET) (designated as ET-33/LWT-26), three Space Shuttle main engines (SSME's) (serial numbers 2019, 2030, and 2029), and two Solid Rocket Boosters (SRB's) (designated as BI-036). The STS-36 mission was a classified Department of Defense mission, and as such, the classified portions of the mission are not discussed. The unclassified sequence of events for this mission is shown in tabular form. Summarized are the significant problems that occurred in the Orbiter subsystems during the mission. The official problem tracking list is presented. In addition, each of the Orbiter problems is cited in the subsystem discussion
STS-41 Space Shuttle mission report
The STS-41 Space Shuttle Program Mission Report contains a summary of the vehicle subsystem activities on this thirty-sixth flight of the Space Shuttle and the eleventh flight of the Orbiter vehicle, Discovery (OV-103). In addition to the Discovery vehicle, the flight vehicle consisted of an External Tank (ET) (designated as ET-39/LWT-32), three Space Shuttle main engines (SSME's) (serial numbers 2011, 2031, and 2107), and two Solid Rocket Boosters (SRB's), designated as BI-040. The primary objective of the STS-41 mission was to successfully deploy the Ulysses/inertial upper stage (IUS)/payload assist module (PAM-S) spacecraft. The secondary objectives were to perform all operations necessary to support the requirements of the Shuttle Backscatter Ultraviolet (SSBUV) Spectrometer, Solid Surface Combustion Experiment (SSCE), Space Life Sciences Training Program Chromosome and Plant Cell Division in Space (CHROMEX), Voice Command System (VCS), Physiological Systems Experiment (PSE), Radiation Monitoring Experiment - 3 (RME-3), Investigations into Polymer Membrane Processing (IPMP), Air Force Maui Optical Calibration Test (AMOS), and Intelsat Solar Array Coupon (ISAC) payloads. The sequence of events for this mission is shown in tabular form. Summarized are the significant problems that occurred in the Orbiter subsystems during the mission. The official problem tracking list is presented. In addition, each Orbiter problem is cited in the subsystem discussion
STS-35 Space Shuttle mission report
The STS-35 Space Shuttle Program Mission Report contains a summary of the vehicle subsystem activities during this thirty-eighth flight of the Space Shuttle and the tenth flight of the Orbiter vehicle Columbia (OV-102). In addition to the Columbia vehicle, the flight vehicle consisted of an External Tank (ET) (designated as ET-35/LWT-28), three Space Shuttle main engines (SSME's) (serial numbers 2024, 2012, and 2028 in positions 1, 2, and 3, respectively), and two Solid Rocket Boosters (SRB's) designated as BI-038. The primary objectives of this flight were to successfully perform the planned operations of the Ultraviolet Astronomy (Astro-1) payload and the Broad-Band X-Ray Telescope (BBXRT) payload in a 190-nmi. circular orbit which had an inclination of 28.45 degrees. The sequence of events for this mission is shown in tablular form. Summarized are the significant problems that occurred in the Orbiter subsystems during the mission. The official problem tracking list is presented. In addition, each Orbiter subsystem problem is cited in the applicable subsystem discussion
Three-dimensional simulations of type Ia supernovae
We present the results of three-dimensional hydrodynamical simulations of the
subsonic thermonuclear burning phase in type Ia supernovae. The burning front
model contains no adjustable parameters so that variations of the explosion
outcome can be linked directly to changes in the initial conditions. In
particular, we investigate the influence of the initial flame geometry on the
explosion energy and find that it appears to be weaker than in 2D. Most
importantly, our models predict global properties such as the produced nickel
masses and ejecta velocities within their observed ranges without any fine
tuning.Comment: 7 pages, 5 figures, accepted by A&
Correlations between resonances in a statistical scattering model
The distortion of the regular motion in a quantum system by its coupling to
the continuum of decay channels is investigated. The regular motion is
described by means of a Poissonian ensemble. We focus on the case of only few
channels K<10. The coupling to the continuum induces two main effects, due to
which the distorted system differs from a chaotic system (described by a
Gaussian ensemble): 1. The width distribution for large coupling becomes
broader than the corresponding distribution in the GOE case. 2. Due
to the coupling to the continuum, correlations are induced not only between the
positions of the resonances but also between positions and widths. These
correlations remain even in the strong coupling limit. In order to explain
these results, an asymptotic expression for the width distribution is derived
for the one channel case. It relates the width of a trapped resonance state to
the distance between its two neighboring levels.Comment: 23 pages, 7 Postscript figures. Submitted to Phys. Rev. E, Jan. 9
An Atlas of Spectrophotometric Landolt Standard Stars
We present CCD observations of 102 Landolt standard stars obtained with the
R-C spectrograph on the CTIO 1.5 m telescope. Using stellar atmosphere models
we have extended the flux points to our six spectrophotometric secondary
standards, in both the blue and the red, allowing us to produce flux-calibrated
spectra that span a wavelength range from 3050 \AA to 1.1 \micron. Mean
differences between UBVRI spectrophotometry computed using Bessell's standard
passbands and Landolt's published photometry is found to be 1% or less.
Observers in both hemispheres will find these spectra useful for
flux-calibrating spectra and through the use of accurately constructed
instrumental passbands be able to compute accurate corrections to bring
instrumental magnitudes to any desired standard photometric system
(S-corrections). In addition, by combining empirical and modeled spectra of the
Sun, Sirius and Vega, we calculate and compare synthetic photometry to observed
photometry taken from the literature for these three stars.Comment: Added referee's comments, minor corrections, replaced Table 1
The distribution of supermassive black holes in the nuclei of nearby galaxies
The growth of supermassive black holes by merging and accretion in
hierarchical models of galaxy formation is studied by means of Monte Carlo
simulations. A tight linear relation between masses of black holes and masses
of bulges arises if if the mass accreted by supermassive black holes scales
linearly with the mass forming stars and if the redshift evolution of mass
accretion tracks closely that of star formation. Differences in redshift
evolution between black hole accretion and star formation introduce
considerable scatter in this relation. A non-linear relation between black hole
accretion and star formation results in a non-linear relation between masses of
remnant black holes and masses of bulges. The relation of black hole mass to
bulge luminosity obseved in nearby galaxies and its scatter are reproduced
reasonably well by models in which black hole accretion and star formation are
linearly related but do not track each other in redshift. This suggests that a
common mechanism determines the efficiency for black hole accretion and the
efficiency for star formation, especially for bright bulges.Comment: 6 pages, 3 figures, submitted to MNRA
Towards a Stable Numerical Evolution of Strongly Gravitating Systems in General Relativity: The Conformal Treatments
We study the stability of three-dimensional numerical evolutions of the
Einstein equations, comparing the standard ADM formulation to variations on a
family of formulations that separate out the conformal and traceless parts of
the system. We develop an implementation of the conformal-traceless (CT)
approach that has improved stability properties in evolving weak and strong
gravitational fields, and for both vacuum and spacetimes with active coupling
to matter sources. Cases studied include weak and strong gravitational wave
packets, black holes, boson stars and neutron stars. We show under what
conditions the CT approach gives better results in 3D numerical evolutions
compared to the ADM formulation. In particular, we show that our implementation
of the CT approach gives more long term stable evolutions than ADM in all the
cases studied, but is less accurate in the short term for the range of
resolutions used in our 3D simulations.Comment: 17 pages, 15 figures. Small changes in the text, and a change in the
list of authors. One new reference adde
- …