Zonal Wind Calculations from Mars Global Surveyor Accelerometer and Rate Data

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76565/1/AIAA-28588-795.pd

Calculation of Zonal Winds using Accelerometer and Rate Data from Mars Global Surveyor

The Mars Global Surveyor spacecraft was initially placed into a high eccentricity, nearly polar orbit about Mars with a 45-hour period. To accomplish the science objectives of the mission, a 2-hour, circular orbit was required. Using a method known as aerobraking, numerous passes through the upper atmosphere slowed the spacecraft, thereby reducing the orbital period and eccentricity. To successfully perform aerobraking, the spacecraft was designed to be longitudinally, aerodynamically stable in pitch and yaw. Since the orbit is nearly polar, the yaw orientation of the spacecraft was sensitive to disturbances caused by the zonal components of wind (east-to-west or west-to-east) acting on the spacecraft at aerobraking altitudes. Zonal wind velocities were computed by equating the aerodynamic and inertia-related torques acting on the spacecraft. Comparisons of calculated zonal winds with those computed from the Mars Thermospheric Global Circulation Model are discussed

A Client-Satisfaction-Based Model of Urban Public Service Delivery Organizational Effectiveness

This article proposes a model for measuring the performance of urban public service delivery agencies. It also presents the results of the model\u27s application to a case study involving urban housing policy organizations (HPOs) in Cameroon. The model incorporates consumer satisfaction, an obvious indicator of the effectiveness construct that is conspicuously lacking in extant models of organizational effectiveness. By incorporating this indicator, the model is potentially useful to especially city government officials interested in evaluating local public service delivery agencies from the point of view of those they profess to serve, the citizens

Malaria: progress, perils, and prospects for eradication

There are still approximately 500 million cases of malaria and 1 million deaths from malaria each year. Yet recently, malaria incidence has been dramatically reduced in some parts of Africa by increasing deployment of anti-mosquito measures and new artemisinin-containing treatments, prompting renewed calls for global eradication. However, treatment and mosquito control currently depend on too few compounds and thus are vulnerable to the emergence of compound-resistant parasites and mosquitoes. As discussed in this Review, new drugs, vaccines, and insecticides, as well as improved surveillance methods, are research priorities. Insights into parasite biology, human immunity, and vector behavior will guide efforts to translate parasite and mosquito genome sequences into novel interventions