The SPQR experiment: detecting damage to orbiting spacecraft with ground-based telescopes

2007 ◽  
Vol 19 (5-6) ◽  
pp. 65-69 ◽  
Author(s):  
Antonio Paolozzi ◽  
Manfredi Porfilio ◽  
Douglas G. Currie ◽  
Ronald F. Dantowitz
Keyword(s):  
Orbiting Spacecraft

Night Airglow Observations from Orbiting Spacecraft Compared with Measurements from Rockets

Science ◽  
1963 ◽  
Vol 140 (3571) ◽  
pp. 1087-1089 ◽  
Author(s):  
M. J. Koomen ◽  
I. S. Gulledge ◽  
D. M. Packer ◽  
R. Tousey
Keyword(s):  
Orbiting Spacecraft ◽  
Night Airglow

scholarly journals Pc2-3 geomagnetic pulsations on the ground, in the ionosphere, and in the magnetosphere: MM100, CHAMP, and THEMIS observations

2015 ◽  
Vol 33 (1) ◽  
pp. 117-128 ◽  
Author(s):  
N. Yagova ◽  
B. Heilig ◽  
E. Fedorov
Keyword(s):  
Amplitude Ratio ◽  
Wave Transmission ◽  
Alfven Wave ◽  
Occurrence Rate ◽  
Full Wave ◽  
Quality Signals ◽  
Rate Maximum ◽  
L Value ◽  
Orbiting Spacecraft ◽  
Shear Alfven Waves

Abstract. We analyze Pc2-3 pulsations recorded by the CHAMP (CHAllenging Minisatellite Payload) satellite in the F layer of the Earth's ionosphere, on the ground, and in the magnetosphere during quiet geomagnetic conditions. The spectra of Pc2-3 pulsations recorded in the F layer are enriched with frequencies above 50 mHz in comparison to the ground Pc2-3 spectra. These frequencies are higher than the fundamental harmonics of the field line resonances in the magnetosphere. High quality signals with dominant frequencies 70–200 mHz are a regular phenomenon in the F layer and in the magnetosphere. The mean latitude of the maximum Pc2-3 occurrence rate lies at L ≈ 3.5 in the F layer, i.e., inside the plasmasphere. Day-to-day variations of the L value of the CHAMP Pc2-3 occurrence rate maximum follow the plasmapause day-to-day variations. Polarization and amplitude of Pc2-3s in the magnetosphere, in the ionosphere, and on the ground allow us to suggest that they are generated as fast magnetosonic (FMS) waves in the outer magnetosphere and are partly converted into shear Alfven waves near the plasmapause. The observed ground-to-ionosphere amplitude ratio during the night is interpreted as a result of the Alfven wave transmission through the ionosphere. The problem of wave transmission through the ionosphere is solved theoretically by means of a numerical solution of the full-wave equation for the Alfven wave reflection from and transmission through a horizontally stratified ionosphere. The best agreement between the calculated and measured values of the ground-to-ionosphere amplitude ratio is found for k = 5 × 10−3 km−1, i.e., the observed ground-to-ionosphere amplitude ratio corresponds to a wave spatial scale which could provide a Doppler shift within a few percent of the apparent frequency of the Pc2-3 pulsations as recorded by a low-orbiting spacecraft.

scholarly journals Corrections for Temporal Discontinuities in the OPI

2010 ◽  
Vol 27 (3) ◽  
pp. 457-469 ◽  
Author(s):  
M. R. P. Sapiano ◽  
J. E. Janowiak ◽  
P. A. Arkin ◽  
H. Lee ◽  
T. M. Smith ◽  
...  
Keyword(s):  
High Resolution ◽  
Longwave Radiation ◽  
Infrared Observations ◽  
Tropical Precipitation ◽  
Corrected Version ◽  
Crossing Time ◽  
Orbital Drift ◽  
Mean Square Difference ◽  
The Tropics ◽  
Orbiting Spacecraft

Abstract The longest record of precipitation estimated from satellites is the outgoing longwave radiation (OLR) precipitation index (OPI), which is based on polar-orbiting infrared observations from the Advanced Very High Resolution Radiometer (AVHRR) instrument that has flown onboard successive NOAA satellites. A significant barrier to the use of these data in studies of the climate of tropical precipitation (among other things) is the large bias caused by orbital drift that is present in the OLR data. Because the AVHRR instruments are deployed on the polar-orbiting spacecraft, OLR observations are recorded at specific times for each earth location for each day. Discontinuities are caused by the use of multiple satellites with different observing times as well as the orbital drift that occurs throughout the lifetime of each satellite. A regression-based correction is proposed based solely on the equator crossing time (ECT). The correction allows for separate means for each satellite as well as separate coefficients for each satellite ECT. The correction is calculated separately for each grid box but is applied only at locations where the correction is correlated with the OLR estimate. Thus, the correction is applied only where deemed necessary. The OPI is used to estimate precipitation from the OLR estimates based on the new corrected version of the OLR, the uncorrected OLR, and two earlier published corrected versions. One of the earlier corrections is derived by removing variations from AVHRR based on EOFs that are identified as containing spurious variations related to the ECT bias, whereas the other is based on OLR estimates from the High Resolution Infrared Radiation Sounder (HIRS) that have been corrected using diurnal models for each grid box. The new corrected version is shown to be free of nearly all of the ECT bias and has the lowest root mean square difference when compared to gauges and passive microwave estimates of precipitation. The EOF-based correction fails to remove all of the variations related to the ECT bias, whereas the correction based on HIRS removes much of the bias but appears to introduce erroneous trends caused by the water vapor signal to which these data are sensitive. The new correction for AVHRR OLR works well in the tropics where the OPI has the most skill, but users should be careful when interpreting trends outside this region.

scholarly journals Linear Approach to the Orbiting Spacecraft Thermal Problem

2012 ◽  
Vol 26 (3) ◽  
pp. 511-522 ◽  
Author(s):  
José Gaite ◽  
Germán Fernández-Rico
Keyword(s):  
Thermal Problem ◽  
Linear Approach ◽  
Orbiting Spacecraft

scholarly journals Ground station scheduling optimization for a model of a real-world problem instance

2021 ◽  
Author(s):  
Bryce Wildish
Keyword(s):  
Real World ◽  
Heuristic Algorithms ◽  
Complex Problem ◽  
Initial Guess ◽  
Fine Tuning ◽  
Problem Instance ◽  
Ground Station ◽  
Real World Problem ◽  
Crucial Component ◽  
Orbiting Spacecraft

Effective scheduling of communication windows between orbiting spacecraft and ground stations is a crucial component of efficiently using spacecraft resources. In all but the most trivial cases, this forces the operator to choose a subset of the potentially available access windows such that they can achieve the best possible usage of their hardware and other resources. This is a complex problem not normally solvable analytically, and as a result the standard approach is to apply heuristic algorithms which take an initial guess at a solution and improve upon it in order to increase its quality. Various such algorithms exist, with some being in common practice for this particular problem. This thesis covers the application of several of the most commonly-used algorithms on a problem instance. Additionally, a real-world problem instance is used, and the resultant practical constraints are addressed when applying the heuristics and fine-tuning them for this application.

scholarly journals Towards the utilization of optical ground-to-space links for low earth orbiting spacecraft

2020 ◽  
Vol 166 ◽  
pp. 147-155 ◽  
Author(s):  
Marcus T. Knopp ◽  
Andreas Spoerl ◽  
Marcin Gnat ◽  
Gregor Rossmanith ◽  
Felix Huber ◽  
...  
Keyword(s):  
Orbiting Spacecraft

Orbital Dynamics System of TUBITAK UZAY for Earth Orbiting Spacecraft

2019 ◽  
Author(s):  
Egemen Imre ◽  
Burak Yaglioglu ◽  
Murat Gokce ◽  
Mehmet Rauf Geden ◽  
Abdulkadir Koker ◽  
...  
Keyword(s):  
Orbital Dynamics ◽  
Orbiting Spacecraft

Improved force modeling on Mars-Orbiting spacecraft

2008 ◽  
Author(s):  
Erwan Mazarico ◽  
Maria Zuber ◽  
Frank Lemoine ◽  
David Smith
Keyword(s):  
Force Modeling ◽  
Orbiting Spacecraft

scholarly journals Assessment of a portable clinical blood analyzer during space flight

1997 ◽  
Vol 43 (6) ◽  
pp. 1056-1065 ◽  
Author(s):  
Scott M Smith ◽  
Janis E Davis-Street ◽  
Tina B Fontenot ◽  
Helen W Lane
Keyword(s):  
Space Shuttle ◽  
Medical Data ◽  
Ionized Calcium ◽  
Sample Collection ◽  
Laboratory Methods ◽  
Remote Locations ◽  
Fluid Redistribution ◽  
Reliable Instrument ◽  
Orbiting Spacecraft ◽  
Control Samples

Abstract This study was designed to validate the utility of a commercial portable clinical blood analyzer (PCBA) in ground-based studies and on the space shuttle. Ionized calcium, pH, electrolytes, glucose, and hematocrit were determined. Results agreed well with those from traditional laboratory methods, and the PCBA demonstrated good between-day precision for all analytes. In-flight analysis of control samples revealed differences in one analyte (sodium). There were few changes in crew members’ results during flight, and these were expected. Potassium increased in flight compared with before flight, and potassium, pH, and hematocrit decreased after flight. Ionized calcium was decreased in flight and on landing day. Changes during flight were likely related to sample collection technique. Postflight changes likely reflected the fluid redistribution that occurs after exposure to weightlessness. These data confirm that the PCBA is a reliable instrument for most analytes, and can provide important medical data in remote locations, such as orbiting spacecraft.

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