Numerous studies have indicated that the microgravity environment of space has harmful effects on several tissues throughout the body. Although this phenomenon is well documented, research in this area is still in its relative infancy. This study investigates the effects of space flight on mucin production of the uterine tubes of mice. This study examined the epithelium of the uterine tubes from female mice that were flown on the space shuttle Endeavour for 13 days in August, 2007 and their concomitant controls. The tissue was qualitatively analyzed for the type of mucin produced, i.e.; acidic, neutral, acidic/neutral mixture. Further, the tissue was quantitatively analyzed for the amounts of mucins produced by measuring the thickness of the mucin layer for each region of the uterine tube: isthmus, ampulla, and infundibulum. One way ANOVA tests were used to compare mucin thickness between all three sets of animals. Results indicate similar but not identical results between the three regions of the uterine tube. The Baseline tissue had the thickest mucin layer regardless of treatment group. In the ampulla the mucin layer was the thinnest in the Flight tissue, followed by the Ground Control, with the Baseline being the thickest. Analysis of the mucin layer of the infundibulum of the three treatment groups indicated no difference in its thickness between the three regions of the uterine tube. These results indicate a trend toward thinning of the mucin layer of the uterine tube in space flight, but also indicate an influence by the housing environment.

Numerous studies have indicated that the microgravity environment of space has harmful effects on several tissues throughout the body. Although this phenomenon is well documented, research in this area is still in its relative infancy. This study investigates the effects of space flight on mucin production of the uterine tubes of mice. This study examined the epithelium of the uterine tubes from female mice that were flown on the space shuttle Endeavour for 13 days in August, 2007 and their concomitant controls. The tissue was qualitatively analyzed for the type of mucin produced, i.e.; acidic, neutral, acidic/neutral mixture. Further, the tissue was quantitatively analyzed for the amounts of mucins produced by measuring the thickness of the mucin layer for each region of the uterine tube: isthmus, ampulla, and infundibulum. One way ANOVA tests were used to compare mucin thickness between all three sets of animals. Results indicate similar but not identical results between the three regions of the uterine tube. The Baseline tissue had the thickest mucin layer regardless of treatment group. In the ampulla the mucin layer was the thinnest in the Flight tissue, followed by the Ground Control, with the Baseline being the thickest. Analysis of the mucin layer of the infundibulum of the three treatment groups indicated no difference in its thickness between the three regions of the uterine tube. These results indicate a trend toward thinning of the mucin layer of the uterine tube in space flight, but also indicate an influence by the housing environment.

A systems engineering approach was used to produce a preliminary design configuration for an ion-propelled orbital transfer vehicle system. The four components of the system are: ground software, ground hardware, the orbital transfer vehicle and the space shuttle. The orbital transfer vehicle uses electrostatic propulsion to transfer payload satellites from a low earth orbit, to any other desired orbit. The system maintenance concept, and a conceptual design are derived from the statement of need and the system operational requirements. The resulting design, maintainability, reliability and support requirements are discussed. A discussion of the feasibility of an ion propelled orbital transfer vehicle is included. / Master of Science

Manned Spacecraft Programs are the largest research and development tasks ever undertaken by the government or by private industry in the United States. Under the direction of the National Aeronautic and Space Administration (NASA) these programs have advanced from Project Mercury in the early 1960's through Gemini, Apollo, including Moon Landing, and Skylab Programs to the present day Space Shuttle Program. With the development of each new program, there comes a growing awareness of the ever increasing complexity of tasks relating to integrated preflight test and checkout. Data rates have grown from one (1) pulse amplitude modulated/frequency modulated (PAM/FM) link with just over a hundred (100) measurements to multiple pulse code modulated (PCM) links with many thousands of measurements and bit rates up to fifty (50) megabits per second (MBPS). A unique requirement of Manned Spacecraft Programs in the "Man Rating" concept. Man rating requires that every failure and test anomaly be analyzed, understood and/or corrected prior to flight. This further complicates an already complex test and checkout program. Exploitation of the potentials of automation was and is the only recourse for present day and future programs. Such automation should be as automatic as possible but must have a man-in-the-loop capability to assure that the test engineer has positive control at all times. This paper analyzes the progress in automation in round test and checkout from Project Mercury days with a simplified prototype technique for Space Shuttle.

Crew motions can affect the angular orientation of a spacecraft. Such motions are of a somewhat random nature and must be treated stochastically. The equations of motion for the spacecraft are solved to obtain a simple relationship between individual crew motions and the angular change in spacecraft orientation. For the majority of manned spacecraft, the angular changes about the three principal axes of inertia can be considered independent. The additive effect of many motions, considered random in frequency and magnitude, is found by treating the motion as a form of random walk. Solutions are obtained for the time required to reach predetermined maximum allowable angular deviation limits. If reaction control jets are used for stabilization, this time determines the frequency of firing and the fuel consumption rate. For relatively heavy spacecraft, such as those designed to carry three or more crew members, the complete solution to the diffusion equation gives the time between control jet firing; this solution has a particularly simple form. For smaller spacecraft, where individual motions may cause a change in orientation which is several percent of the maximum allowable, additional solutions have been obtained using Markov chain matrix analysis; numerical values for the matrix equations can be obtained from a digital computer. / Ph. D.

Analysis of the flow field in a laser engine represents a difficult computational problem involving combinations of complex physical and gas-dynamical processes. Following a brief discussion of these processes a calculation procedure using primitive variables formulation on a non-staggered grid system is introduced. Based on this procedure, a Pressure Based Navier-Stokes Solver (PBNS) is developed using a generalized curvilinear coordinate system. The solver is first tested in application to a subsonic compressible flow over an insulated flat plate and to a flow in an axisymmetric converging-diverging nozzle. Next, the PBNS code is used to analyze the flowfield and performance of a laser thruster. The physical/numerical model includes the geometric ray tracing for the laser beam, beam power absorption, plasma radiation losses, and plasma thermophysical and optical properties. Equilibrium hydrogen is used as a flowing gas and its properties are calculated using the Hydrogen Properties Calculation (HPC) based on the the methods of statistical thermodynamics. Two thruster configurations, two laser types (CO₂ and iodide), various laser power levels, and various injection conditions are tested. The results of these tests include the temperature, pressure, velocity and Mach number contours, as well as table of the laser beam power absorbed, radiation losses to the thruster walls, thrust level and specific impulse. The maximum specific impulse obtained in these tests is 1537 sec for a CO₂ laser thruster and 827 sec for an iodide laser thruster. Up to 100% power absorption can be achieved, however, the radiation losses from the hot plasma are quite high disallowing a full conversion of the absorbed power into the thermal energy of the propellant. The PBNS code can be used to study the effects of various design parameters on the performance of a laser thruster and provide guidelines for the preliminary design of a laser engine. / Ph. D.

The use of aerodynamic forces to assist in certain orbital transfers can greatly reduce the fuel consumption as compared with corresponding all-propulsive transfers. Therefore, in seeking minimum fuel trajectories, aeroassisted transfers need to be investigated. A review of the current literature indicates that such problems have been solved almost exclusively via optimal control theory formulations that result in continuously varying control laws. The use of a piecewise-constant strategy allows the controls to vary to a degree necessary to affect changes in the desired state dependent parameters while simplifying the optimization process. In the process of searching for a tool to produce numerical results, the current research investigates three candidate methods of solving the parameter optimization problem of minimum fuel aeroassisted orbital transfer with piecewise-constant controls. A method based on implicitly integrating the state trajectory is chosen over methods which analytically and explicitly integrate the state trajectory. The implicit method offers improved performance over the explicit method while presenting a more correct solution than the analytic method. The analytic method is shown to suffer from approximations that lead to undesirable solutions. Analytic expressions for the characteristic velocities of Hohmann and idealized aeroassisted transfers are presented and compared. For a large number of transfers from high Earth orbit to low Earth orbit, the aeroassisted mode requires less fuel. Numerical results are presented for minimum fuel transfer from geosynchronous Earth orbit to low earth orbit for a variety of control strategies. The piecewise-constant strategies are seen to provide solutions which are comparable to those found via optimal control theory. / Master of Science

There are critical questions we must engage in before we ever set foot or flag on Mars. Why do we go? How do we convince ourselves it is worth it? In this work, I will analyze the current discourse of Mars. Mars is legitimized as a place through a form of discourse whose roots can be traced back to earlier, colonial forms of discourse. Modernity acts as a normative force by limiting our language to established forms of discourse, like Hegelian notions of progress, while marginalizing other possibilities of narrative. The colonial gaze is only one possible way we have to understand Mars. What is necessary now is to perform the great Foucaultian task of seeking out lost narratives and lost knowledges of our past. I will examine how the power of narrative has been used to convince the public that we should go to Mars. Modernity has phenomenologically shaped Mars and our present discourse of Mars is the result of that metamorphosis. Narratives of science-fiction, science advocacy, special interest groups, and government bureaucracy reflect the modern notions that pervade Areological discourse, thereby promoting a colonial gaze of Mars. Modernity represents a way of seeing Mars that has been pushed upon us by history, eliminating alternate narratives of place through the nonnative practice of modern thinking.

Thesis (M.S.)--Mississippi State University. Department of Aerospace Engineering. / Title from title screen. Includes bibliographical references.

This thesis explores how an Asteroid Sample Return Mission might make use of solar electric propulsion to send a spacecraft on a journey to the asteroid 1989ML and back. It examines different trajectories that can be used to get an asteroid sample return or similar spacecraft to an interplanetary destination and back in the most fuel-efficient manner. While current plans call for keeping such a spacecraft on the asteroid performing science experiments for approximately 90 days, it is prudent to inquire how lengthening or shortening this time period may affect mission fuel requirements. Using optimal control methods, various mission scenarios have been modeled and simulated. The results suggest that the amount of time that the spacecraft may spend on the asteroid surface can be approximated as a linear function of the available fuel mass. Furthermore, It can be shown that as maximum available thrust is decreased, the radial component of the optimal thrust vector becomes more pronounced.