AuthorWithers, Paul G.
KeywordsPhysics, Astronomy and Astrophysics.
AdvisorBougher, Stephen W.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractThe dynamics of the martian upper atmosphere are not well-understood. I have identified the dominant tidal modes present in the upper atmosphere by comparing density measurements from the aerobraking of the Mars Global Surveyor spacecraft to predictions from classical tidal theory. Other observations and general circulation models have also provided constraints. I have presented a justification for why topography has a strong influence on the tides in the upper atmosphere. I have also studied sol-to-sol variations in density at fixed altitude, latitude, longitude, season, and time of day. I have developed a novel "Balanced Arch" technique to derive pressures and temperature from these density measurements that also estimates the zonal wind speed in the atmosphere. These are the first measurements of winds in the martian upper atmosphere. This technique can also be applied to anticipated data from Titan to measure winds in its upper atmosphere. I have developed techniques to derive density, pressure, and temperature profiles from entry accelerometer data, used them to investigate the entry of Mars Pathfinder, and discovered that surprisingly accurate temperature profiles can be derived without using any aerodynamic information at all. I have also investigated techniques to derive atmospheric properties from the Doppler shift in telemetry from a spacecraft during atmospheric entry and found that a surprisingly robust estimate of temperature at peak acceleration can be derived. I have discovered a network of tectonic ridges in the otherwise bland northern plains of Mars and studied their implications for a possible ocean in that area. I have tested the hypothesis that the formation of lunar crater Giordano Bruno was witnessed in 1178 AD and rejected it due to the lack of any observations of the immense meteor storm that must have followed the crater's formation.
Degree ProgramGraduate College