Upper Atmospheric Modeling for Mars Global Surveyor Aerobraking Using Least Squared Processes
Abstract
Mars Global Surveyor (MGS) will be performing an aerobraking maneuver to move from its highly elliptical initial orbit to its final nearly circular mapping orbit. This maneuver will occur from September 1997 to approximately September 1998. To accomplish this maneuver safely and quickly, it will be necessary to accurately know the atmospheric environment at aerobraking altitudes (approximately 100-140 kilometers above the surface of the planet). One way of accomplishing this is by using accelerometer data from the spacecraft. The method of least squares is used to fit density measurements determined from the accelerometer data, which results in an empirical model that characterizes the atmosphere. This can be done by breaking the data up into regions of interest or by taking the entire data set, resulting in different types of atmospheric information. The hydrostatic equation is the governing equation for the models assuming three different temperature profiles: constant, linear, and Bates. The least squares solution yields information about density, temperature, scale height, pressure, and atmospheric variability. This information is fed back to the navigation team and the atmospheric advisory group to aid in the orbital correction decision making process. Also, this information will be compared over time to determine latitudinal, diurnal, and seasonal trends in the Martian atmosphere. This will lead to a more accurate atmospheric model than those currently being used.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 17, 1998
- Accession Number
- ADA351443
Entities
People
- Brandon Wilkerson
Organizations
- George Washington University