The dynamics and modeling of the thermosphere has been of great interest to scientists and LEO spacecraft operators since the first earth satellites were constructed. Although a great deal of data has been accumulated regarding the average conditions, or climate, of the atmosphere in this region, at the time of writing, much ongoing work remains to be done to verify or characterize crucial transient phenomena such as tides and propagating disturbances [Bruinsma 2006]. The contribution of often unmeasured in-track winds and the use of constant drag coefficients in spacecraft drag measurements [Bowman and Moe 2005] has introduced 10-15% errors into the atmospheric models which rely on this data as a source of density values. To address these in-situ measurement issues, a novel method of drag determination is proposed, modeled, and combined with a wind measurement method as well as a numerical tool for calculating the coefficient of drag of complex geometries. This analysis and error model will be applied to the Drag and Atmospheric Neutral Density Explorer (DANDE) and its instruments. DANDE is a satellite being developed at the University of Colorado and will be a low earth orbiting spacecraft with the capability to study in-situ winds, composition, and density.
A method is presented here which will serve as an error analysis of the measurements and which can be extended to other in-situ missions with similar instruments. This will include the modeling of the spacecraft and its sensors, the input from the ambient environment, on-board data analysis, and gas-surface interactions causing the measured forces on the spacecraft.
In the course of the analysis, it is demonstrated that DANDE will meet its required drag measurement fidelities. We also show how the presence of solar cells (raised features) on the spherical spacecraft changes the drag coefficient and calculate the overall uncertainty during solar maximum and solar minimum conditions.
|Commitee:||Forbes, Jeffrey, Fuller-Rowell, Tim|
|School:||University of Colorado at Boulder|
|School Location:||United States -- Colorado|
|Source:||MAI 47/01M, Masters Abstracts International|
|Subjects:||Aerospace materials, Atmosphere|
|Keywords:||Accelerometer, Drag coefficient, Measurement model, Neutral density|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be