Space Vehicles Commons^™

Aerothermodynamic Analysis Of A Mars Sample Return Earth-Entry Vehicle, Daniel A. Boyd

Mechanical & Aerospace Engineering Theses & Dissertations

Because of the severe quarantine constraints that must be imposed on any returned extraterrestrial samples, the Mars sample return Earth-entry vehicle must remain intact through sample recovery. Vehicles returning on a Mars-Earth trajectory will attain velocities exceeding any that have been experienced by prior space exploration missions, with velocities approaching 14 km/s. Velocities as high as these will encounter significant heating during atmospheric re-entry to Earth.

The purpose of this study has been to systematically investigate the aerothermodynamic challenges that will result from a Mars sample return, Earth-entry vehicle design. The goal was to enable efficient estimation of maximum stagnation …

Design Improvements For A Reusable Horizontal Takeoff And Landing Aircraft For Use On Mars, Brian A. Skoog

Mechanical & Aerospace Engineering Theses & Dissertations

Unmanned aerial vehicle capabilities are required for expanded exploration of the Martian surface. These vehicles can not only gather data at an altitude otherwise unreachable by rovers and satellites, but also deliver small payloads and retrieve samples from distant off-site locations. Previous multi-purpose reusable Mars aircraft studies have been unable to achieve the flight ranges required for expanded exploration. This study has focused on increasing the range of prototype aircraft designs. Assuming that large precision cargo delivery capabilities have been developed and much of the infrastructure associated with a fixed Mars base is in place, the challenge of linking dispersed …

Conceptual Design Of A Reusable Mars Aircraft, Bryce L. Horvath

Mechanical & Aerospace Engineering Theses & Dissertations

This study assumes that the launch vehicles and precision Mars entry descent and landing systems, required for eventual crewed missions to the surface, have been developed, motivating the rapid build-up of a fixed surface base to enable extended human stays. During the time interval between the first successful placement of a heavy (between 20 and 80 metric ton) payload and completion of the baseline human-rated Mars outpost, it will be possible to utilize this large payload delivery capability to accelerate robotic exploration of the surface from the fixed base location.

One element of such an expanded robotic exploration program will …

Mars Carbon Dioxide Propulsion, Christopher Cushman Perry

Mechanical & Aerospace Engineering Theses & Dissertations

An experimental investigation was conducted to characterize the performance of a small-scale supersonic propulsion system using supercritical CO₂ as a propellant intended for Mars surface applications. This research has focused on estimating the specific impulse behavior of high-pressure carbon dioxide propellant that can be produced by condensing dry ice out of Mars's atmosphere and heating it at constant volume to temperatures above its 31.1 ° C critical temperature. Since supercritical fluid was created by heating different dry ice-vapor mixtures to moderate temperatures, the nominal initial density and thermodynamic state within the pressure vessel could be controlled. The instrumented test …

A 6-Dof Force Transducer Design From An Existing Rocket Payload Attachment Fitting, Thomas H. Johnson

Mechanical & Aerospace Engineering Theses & Dissertations

Lack of reliable in-flight data regarding the forces experienced by a spacecraft inside a Boeing Delta II rocket have led to the need for a simple and cost effective force measurement solution. This research investigates one solution that creates a direct reading force transducer to monitor the forces and moments experienced by the spacecraft rather than inferring forces from accelerometer readings as is currently practiced. In order to minimize costs, it is desired that the transducer is designed out of the existing structure that connects the spacecraft to the second stage. The existing structure is called a Payload Attachment Fitting …

Propulsion Enhancement Contributions To The Performance Of Space Launch Vehicles, Russell H. Edwards

Mechanical & Aerospace Engineering Theses & Dissertations

A research effort has been undertaken to investigate critical aspects of launch vehicle performance as affected by variations in specific launch vehicle parameters. The major portion of the study involves liquid propellant systems. However, since solid propellant systems also play a role in today's launch systems, a representative solid-propellant launch vehicle has also been analyzed. The research undertaken determined that the payload capability of a space launch vehicle, or, conversely, the vehicle total liftoff mass, is highly sensitive to the manner in which the space launch vehicle is staged. The research has led to the development and programming of a …

Spacecraft Trajectory Design For Short Duration Near Earth Asteroid Missions, Synthia Mirlin Findlay

Mechanical & Aerospace Engineering Theses & Dissertations

Design of orbital trajectories using patched conic approximation methodology for short duration missions to newly detected, incoming near Earth asteroids, which are on close approach trajectories with Earth, is the focus of this thesis. The primary purpose for such missions is two fold. First, near Earth asteroids provide unique mission opportunities for solar system science where the celestial body of interest transits to Earth proximity and is studied in situ by probes having short duration trajectories, rather than sending long distance probes to the celestial body. Second, improved characterization of asteroid properties, compositions, and orbital states for reduction of uncertainties …

Contemporary-Classical Sequential Loop Design With Parameter Uncertainty, Donghyuk Jeong

Mechanical & Aerospace Engineering Theses & Dissertations

Standard sequential loop closure design based on Evans root migration concepts is a well accepted, insightful and effective technique for meeting nominal performance objectives and traditional gain-phase stability margin requirements. Unfortunately, assessment of closed-loop variations resulting from parameter error is a post-process, implying an undesirable design-assess-redesign procedure is necessary if variations are found unacceptable. Further, the modem parameter uncertainty assessment framework is often inconsistent, both quantitatively and qualitatively, with the redesign task. Specifically, the parameter uncertainty assessment variables are not readily apparent in the sequential loop design framework, and these variables provide little guidance for the redesign strategy. Therefore, enhancing …

New Methodology For Robust Control System Design And Analysis For Single Parameter Uncertain Systems, Charles J. Player

Mechanical & Aerospace Engineering Theses & Dissertations

Due to the conservative nature of the standard singular value robustness tests there is ambiguity in the results that they provide. The tests only establish a sufficient condition and therefore provide little insight to the stability robustness of a system that fails the test. However, for a single parameter uncertain system that is modeled using structured uncertainty, an Evans root locus can be derived that shows how system closed-loop poles change with the magnitude of the single parameter uncertainty. This technique provides clear stability robustness insight. Further, another Evans root locus can be derived that shows how system closed-loop zeros …

Transonic And Supersonic High Alpha Flow Prediction And Control For An Sc-X Space Vehicle, Ruobo You

Mechanical & Aerospace Engineering Theses & Dissertations

Universal Space Line (USL) is interested in developing an aerospace vehicle that flies at very high angles of attack (AOAs) through wide range of Mach numbers. The basic model configuration is called SC-X model, which consists of a blunt cone and a cylindrical afterbody. A structured O-type grid was generated for this model by numerically solving elliptic partial differential equations. The three-dimensional, unsteady, compressible, Reynolds-averaged Navier-Stokes equations coupled with Spalart-Allmaras turbulence model were used as computational tool to investigate the transonic and supersonic flows around the SC-X model pitched at AOA of 45°. For the code validation, this computational solver …

Linearized Dynamics Of Space Structures With Articulated Appendages, Gopichand Koganti

Mechanical & Aerospace Engineering Theses & Dissertations

The inherent difficulties of the conventional spacecraft design, which first considered the optimization with respect to structural variables and then with respect to control variables, have led to the concept of Controls-Structures Interactive Design. The success of the CSI design of Space structures without articulated appendages has prompted the extension of the CSI design to systems with articulated appendages. The presentation is of two parts, the first part deals with the derivations of the equations of motion and the second part deals with the eigenvalue/vector approximations.

Three approaches, namely: the multibody approach, the finite element based approach with hinge joints …

Thermal Compatibility Analysis Of The Passive Damping Treatment Proposed For The Space Shuttle Remote Manipulator System (Srms), Mahesh Chowdhary

Mechanical & Aerospace Engineering Theses & Dissertations

The NASA Space Shuttle Remote Manipulator System (SRMS), due to its long reach and light weight construction has significant structural flexibility. Thus any routine use of SRMS often results in large amplitude oscillations with long settling time. A passive damping technique utilizing a constrained viscoelastic layer damping treatment has been proposed to augment the active control of these oscillations in order to enhance the system stability and the end effector positional accuracy. This thesis concerns with the thermal compatibility analysis of the proposed damping treatment. The necessity for thermal compatibility analysis arises from the fact that acceptable damping performance of …

Dynamics And Control Of Two Suspension Mechanisms For Ground-Based Testing Of Space Structures, Joseph E. Wilson

Mechanical & Aerospace Engineering Theses & Dissertations

Two suspension systems which effectively simulate a gravity-free environment are presented. A single degree-of-freedom suspension system utilizing a specially profiled band mechanism in conjunction with a torsional spring is presented to show its feasibility and applicability for use as a ground-based testing device for flexible space structures. The second device, a two degree-of-freedom suspension system consisting of two springs and a folding linkage is presented to show the feasibility as a testing device for suspending space structures on earth.

Problems resulting in unwanted dynamic behavior due to deviations from the design parameters for both systems are addressed. A nonlinear controller …

Dynamic Analysis Of An Earth-Orbiting Satellite Deploying Hinged Appendages, Kevin Fielding Oakes

Mechanical & Aerospace Engineering Theses & Dissertations

The planar liberational dynamics of an arbitrary spacecraft with deployable hinged appendages is presented here both analytically and numerically. The system model consists of a central rigid satellite moving about the earth in a circular orbit at a uniform orbital rate. Attached to the satellite are two unfolding rigid booms with specified mass and length. Tip masses are included at the ends of each boom and deployment is driven by torsional springs at both frictionless hinge points. The equations of motion are developed for both a single- and double-appendage model through the use of Lagrange's equations. The formulation accounts for …

On The Space Shuttle Wing Thermal-Structural Analysis, Kumar Krishna Tamma

Mechanical & Aerospace Engineering Theses & Dissertations

A finite element approach for efficient thermal-structural analysis of structures with thermal protection systems (TPS) is described. The approach is applied to Space Shuttle wing structure configurations subjected to reentry heating. New two and three-dimensional finite elements are developed to model heat transfer in the TPS and supporting structure. A typical TPS/Structural element predicts transient nonlinear temperature variations through the TPS thickness and detailed structural temperatures at the TPS/Structure interface. The accuracy of the TPS/Structure approach in two and three-dimensions is evaluated by comparisons with the conventional approach for various configurations of the wing structure. The results indicate that the …

An Approach For Including Reliability In Control System Designs, Ime Isaac Akpan

Mechanical & Aerospace Engineering Theses & Dissertations

An approach is developed for non-catastrophic control component failure accommodation for large space structures. Reliability is considered for both the control configuration (i.e., selecting actuator locations over an admissible set) and the ultimate operation of the system. The approach presented is to construct a measure of performance that indicates the absolute goal of the system, and for a given structural design, to determine the lowest achievable cost conditional upon the failure states of the system (i.e., which actuators are operational). These costs are then weighted and summed to provide an overall system performance measure. This expected performance measure is then …