Air Force Institute of Technology Wright-Patterson Air Force Base, Ohio

By Johnson, Benjamin L., B. S.

Book Id: WPLBN0000173583
Format Type: PDF eBook
File Size: 1.0 MB
Reproduction Date: 2005

Title:	Air Force Institute of Technology Wright-Patterson Air Force Base, Ohio
Author:	Johnson, Benjamin L., B. S.
Volume:
Language:	English
Subject:	Military, Armed Forces., National defense.
Collections:	Military and Armed Forces Library Collection
Historic Publication Date:
Publisher:	Department of Defense


Citation APA MLA Chicago Johnson, B. S, B. L. (n.d.). Air Force Institute of Technology Wright-Patterson Air Force Base, Ohio. Retrieved from http://www.gutenberg.cc/

Description
Government Reference Publication

Excerpt
Introduction: 1.1. Motivation The current capabilities of our space propulsions systems are limiting human operation within and about the space environment. Chemical rocket systems, while necessary for launch operations due to their high thrust characteris tics, do not achieve the highest levels of fuel economy. This economy is measured by a vehicle’s specific impulse (Isp) value which represents the time a rocket can produce one pound of thrust using one pound of fuel. Further complexities within a rocket design are introduced with the choice of relying on chemical propulsion; since both a fuel and oxidizer are required, must be stored separately, and be fed to the combustion chamber. Near earth propulsion systems relying on solar power, while efficient in terms of fuel economy (solar thermal) or requiring no fuel at all (solar- lightsail), lack the thrust required for rapid acceleration and short time-scale missions. The inability of chemical and solar powered spacecraft to both “rapidly and efficiently” operate in the space environment is delaying mankind’s progress in its quest to explore, utilize space assets to better life on Earth, and expand our civilization in such a manner that it allows us to grow as a nation and world community. The new challenges presented by life in space will lead to new ideas, new technologies, 2 and ultimately to an evolution of our society. While there will always be those among us content with living in a society that does no t extend its reach into space, many people now realize the importance of space and the benefits that conquering this domain will have on our way of life (1). Settling this new frontier, or establishing a permanent presence in space is important, and it is rapidly being realized that the use of energy sources other than chemical or solar are needed to make this vision a reality.

Table of Contents
Table of Contents Page Abstract .........................................................................................................................iv Acknowledgments ........................................................................................................vi List of Figures ...............................................................................................................x List of Tables ..............................................................................................................xi Nomenclature ..............................................................................................................xiii 1. Introduction ...........................................................................................................1 1.1 Motivation.......................................................................................................1 1.2 Research Objective .........................................................................................3 1.3 Past Work ........................................................................................................7 2. Background ..........................................................................................................10 2.1 Triggered Isomer Development ...................................................................10 2.2 Radioactive Decay .......................................................................................15 2.2.1 Forms of Radioactive Decay.............................................................15 2.2.2 Attenuation, Absorption, and Emission............................................19 2.2.3 Shielding and Reflecting...................................................................23 2.2.4 Environmental Laws and Regulations ..............................................25 2.3 Nuclear Rocket Development ......................................................................26 2.3.1 Types of Space Nuclear Reactors .....................................................26 2.3.2 Nuclear Engine for Rocket Vehicle Application (NERVA) .............28 2.3.3 Particle Bed Reactor (PBR) ..............................................................30 2.3.4 CERMET ..........................................................................................30 2.3.5 Isotope Thermal Thrusters ................................................................31 3. Methods and Theory ............................................................................................33 3.1 Assumptions.................................................................................................33 3.1.1 Isomer Decay Process .......................................................................33 3.1.2 Rocket Configuration........................................................................34 3.2 Nuclear Fission Reactor Performance .........................................................34 3.3 Rocket Fundamentals ...................................................................................35 3.3.1 Nozzle Analysis ................................................................................35 3.3.2 Conservation of Mass .......................................................................38 viii Page 3.3.3 Power Calculations ...........................................................................39 3.3.4 System Sizing....................................................................................40 3.3.5 Mission Feasibility............................................................................41 3.3.6 Rayleigh Line Analysis .....................................................................43 3.4 Hafnium Requirement..................................................................................44 3.5 Energy Deposition and Fluorescence...............................................