Meso And Micro Scale Propulsion Concepts For Small Spacecraft

A meso/micro scale liquid propellant thruster is being developed for small spacecraft. In this thruster, the liquid propellant was injected directly into the chamber tangentially along the combustor wall. Heat feedback from the flame, once ignited, decomposed and gasified the liquid propellant. The gasification process of the propellant produced a voflex flow in the combustor, which stabilized the gas- phase flame. Modeling studies with gas-phase injection of reactants have shown that the vortex flow creates various flow recirculation patterns depending upon the Reynolds numbers of the flows. Although the propellant of interest was a HAN based liquid propellant, initial studies were conducted with liquid nitromethane. Operation of the combustion chamber with pure nitromethane at chamber pressures as high as 30 atm was studied. To gasify and initially ignite a HAN based propellant, techniques that make use of the electrolytic character of the propellant were investigated. In particular, a continuous flow igniter with titanium electrodes and a gap spacing of 500 Inn was developed and studied. Results showed that a small voltage drop across the electrodes ignites the continuous flow, which can then be removed to achieve a steady-state decomposition process. Methods to further miniature, fabricate, and package the entire system will be investigated in the future.

This book focuses on developing strategies for ultra-lean combustion of natural gas and hydrogen, and contributes to the research on extending the lean flammability limit of hydrogen and air using a hot supersonic jet. The author addresses experimental methods, data analysis techniques, and results throughout each chapter and: Explains the fundamental mechanisms behind turbulent hot jet ignition using non-dimensional analysis Explores ignition characteristics by impinging hot jet and multiple jets in relation to better controllability and lean combustion Explores how different instability modes interact with the acoustic modes of the combustion chamber. This book provides a potential answer to some of the issues that arise from lean engine operation, such as poor ignition, engine misfire, cycle-to-cycle variability, combustion instability, reduction in efficiency, and an increase in unburned hydrocarbon emissions. This thesis was submitted to and approved by Purdue University.

This book reviews the U.S. National Aeronautics and Space Administration's (NASA) small spacecraft technology development. Included are assessments of NASA's technology priorities for relevance to small spacecraft and identification of technology gaps and overlaps. The volume also examines the small spacecraft technology programs of other government agencies and assesses technology efforts in industry.

This book presents the proceedings of SICC 2017, a conference devoted to promoting the dissemination of the different methodologies, techniques, theories, strategies, technologies and best practices on the prevention and mitigation of CBRNE risks. As the first scientific international conference on safety & security issues in the CBRNE field, SICC 2017 attracted contributions resulting from fruitful inter-professional collaborations between university and military experts, specialized operators, decision makers and the industry. As such, these proceedings are primarily intended for academics and professionals from public, private and military entities. It is the first trans-disciplinary collection of scientific papers from the numerous fields related to CBRNE.

A class of miniaturized pulsed plasma thrusters (PPT), known as MicroPPTs, is currently in development at the Air Force Research Laboratory. The MicroPPTs use a surface discharge across solid Teflon(TM) propellant to provide precise impulse bits in the 10 microN-s range. In the near term, these thrusters can provide propulsive attitude control on 150-kg-class spacecraft using 1/5th the dry mass of conventional torque rods and reaction wheels. Eventually these thrusters are designed for primary and attitude control propulsion on future 25-kg class spacecraft envisioned for such missions as formation flying sparse aperture arrays for space-based surveillance, on-orbit satellite servicing, and space control. A synopsis of the status of the thruster is presented, discussing development, lifetime, performance, and environmental testing.

In the past decade, CubeSats have revolutionized small spacecraft missions. These miniature satellites began as educational projects but have lowered the bar for access to space and enabled research institutions and companies to launch technology demonstration and science missions in low Earth orbit. Propulsion systems small enough to fit in a CubeSat can extend the benefits of CubeSats beyond low Earth orbit, and potentially even allow for small-scale interplanetary missions. Propulsion systems designed for CubeSats must overcome severe restrictions in their chemistry, dimensions, mass and operation scheme for the sake of fitting within the CubeSat deployer and conforming to CubeSat specifications. This research presents a novel concept for small satellite propulsion based on the electrolysis of water. These systems are designed to ensure the safety of the launch vehicle and overcome the restrictions imposed by operating as a secondary payload by avoiding the use of hazardous materials, pressure vessels and explosives. Numerical analyses are used to predict the performance of the propulsion system. Vacuum chamber experiments on a prototype of the propulsion system are conducted to determine the performance of the system. An analysis of the attitude dynamics and operation of a satellite with an electrolysis propulsion system are presented. The propulsion system as well as the attitude control of the spacecraft are aided by the spacecraft's spin about its major axis of inertia. Energy damped by the water carried on board keeps the satellite stable and damps nutation caused by external torques and the use of the propulsion system. Several applications are presented for low earth orbit as well as interplanetary CubeSats. The design of a mission to navigate a CubeSat to lunar orbit as part of NASA's CubeQuest Challenge is detailed. Prospects for broader applications of this work involving distributed exploration using in-situ water are identified.

This is a survey of current research on micropropulsion options for very small satellites (less than ten kilogram). The concentration of research and performance evaluations utilize Micro Systems Technology (MST) and Micro Electromechanical Systems technology (MEMS) integrated with existing theories. State of the art methods used for the design and manufacturing of MEMS devices are included to provide a size perspective of microthruster technology. Nine viable microthruster options are presented, including a detailed performance analysis of the pulsed Plasma Thruster. Exploration of the future role of micropropulsion in space is the influential factor benefiting research efforts on extremely small scale microthrusters. significant background information on astrodynamics is included to assist the intended reader: a student of Engineering Science with interest in the Aerospace Propulsion Industry.

"The first objective of this research is to manufacture and investigate the characteristics and use of asymmetric, metallic, nanostructures for plasmonic force propulsion, a developing method of nano-/picosatellite thrust generation. This project developed a higher-fidelity model of a recently envisioned small spacecraft propulsion system for precision pointing and proximity control. Plasmonic force propulsion harnesses solar light focused onto plasmon reactive sub-wavelength nanostructures to generate polarized oscillations of electrons on the surface of metallic nanostructures which accelerate and expel nanoparticle propellant via strong optical forces. This research also explores how material selection affects the electromagnetic response of the closely positioned asymmetric nanostructures. Furthermore, a dielectrophoretic (DEP) nanoparticle injector concept and its use in a plasmonic/photonic-based nanoparticle manipulation system is also described. Particle motion is achieved by generating an electrostatic, non-uniform field between two tilted plates and applying the corresponding DEP force to net-neutral nanoparticles. We investigate the dependence the DEP force has on the plate angle of the charged plates as well as their separation distance, dielectric filler material, and exit interface membrane. Finally we investigate a plasmonic particle acceleration scheme aimed at manipulating high-mass, charged particles such as ions. Analogous to the Alvarez linear accelerator, this plasmon LINAC attempts to harness traveling waves confined to the interior surface of a cylindrical hole in a metallic thin film to impart energy to a low energy, massive particle"--Abstract, page iii.

The NASA Institute for Advanced Concepts (NIAC) was formed in 1998 to provide an independent source of advanced aeronautical and space concepts that could dramatically impact how NASA develops and conducts its missions. Until the program's termination in August 2007, NIAC provided an independent open forum, a high-level point of entry to NASA for an external community of innovators, and an external capability for analysis and definition of advanced aeronautics and space concepts to complement the advanced concept activities conducted within NASA. Throughout its 9-year existence, NIAC inspired an atmosphere for innovation that stretched the imagination and encouraged creativity. As requested by Congress, this volume reviews the effectiveness of NIAC and makes recommendations concerning the importance of such a program to NASA and to the nation as a whole, including the proper role of NASA and the federal government in fostering scientific innovation and creativity and in developing advanced concepts for future systems. Key findings and recommendations include that in order to achieve its mission, NASA must have, and is currently lacking, a mechanism to investigate visionary, far-reaching advanced concepts. Therefore, a NIAC-like entity should be reestablished to fill this gap.