Developed and expanded from the work presented at the New Energetic Materials and Propulsion Techniques for Space Exploration workshop in June 2014, this book contains new scientific results, up-to-date reviews, and inspiring perspectives in a number of areas related to the energetic aspects of chemical rocket propulsion. This collection covers the entire life of energetic materials from their conceptual formulation to practical manufacturing; it includes coverage of theoretical and experimental ballistics, performance properties, as well as laboratory-scale and full system-scale, handling, hazards, environment, ageing, and disposal.
It will be of interest to both postgraduate and final-year undergraduate students in aerospace engineering, and practicing aeronautical engineers and designers, especially those with an interest in propulsion, as well as researchers in energetic materials.
The Georgia Tech AE Propulsion and Combustion Group (P&C) explores the complex systems that compose modern propulsion devices and energy systems. A multi-disciplinary team of faculty and students maintains world-class research, facilities, and academic programs that support this exploration. The group's work focuses on the interplay between complex fluid dynamics and high-temperature chemical and plasma energy conversion processes that underpin propulsion and energy systems.
The P&C group conducts basic, and applied research in combustion, chemical propulsion, and electric propulsion, employing experimental and computational approaches. Specific projects include unsteady phenomena in turbine engine combustors and liquid-fueled rocket engines; the development of nonintrusive, optical-based diagnostic and sensor techniques; the measurement and control of combustion emissions, alternative fuels, plasma-material interactions, facility effects and life limiting processes in electric propulsion devices, and efficient modeling of combustion phenomena at realistic conditions.
Coursework in aerodynamics, materials and structures, propulsion, and dynamics and control of aircraft and spacecraft provide a strong fundamental basis for advanced study and specialization, while senior technical electives offer a concentration of study in fields of special interest. Design is emphasized particularly in senior design electives and a senior-level two-semester design sequence involving specific goals, objectives, and constraints, which integrates analysis and design tools and requires students working in teams to design, and in some cases build, test, and deploy an aerospace system, such as an aircraft, rotorcraft, flight simulator, morphing air or space structure, space suit, space habitat, or a mission to Mars. Application of modern engineering and computational tools is required and emphasized in most courses.
The freshman year is identical for degrees in aerospace engineering, architectural engineering, civil engineering, computer engineering, computer science, electrical engineering, electronic systems engineering technology, environmental engineering, industrial distribution, industrial engineering, interdisciplinary engineering, manufacturing and mechanical engineering technology, mechanical engineering, multidisciplinary engineering technology, nuclear engineering, ocean engineering, and petroleum engineering (Note: not all programs listed are offered in Qatar). The freshman year is slightly different for chemical engineering, biomedical engineering and materials science and engineering degrees in that students take CHEM 119 or CHEM 107/CHEM 117 and CHEM 120. Students pursuing degrees in biological and agricultural engineering should refer to the specific curriculum for this major. It is recognized that many students will change the sequence and number of courses taken in any semester. Deviations from the prescribed course sequence, however, should be made with care to ensure that prerequisites for all courses are met.
Application of thermodynamics and fluid mechanics to basic flow processes and cycle performance in chemical propulsion systems: gas turbines, ramjets, scramjets, and rockets. Introduction to electric and electromagnetic rocket thrusters, nuclear rockets, and solar sails.
Optimization is often necessary in aerospace engineering because of the merciless requirements that physics and chemistry impose on flying systems. For instance, it is well known that to lift 1 kg of payload from Earth's surface to orbit, using chemical rocket propulsion, it is required to use at least 80 kg of rocket structure, engine, fuel, and propellant . This staggering 80/1 ratio is one of many stark reminders that, when it comes to flight, optimization is of the essence.
When in space, the purpose of a propulsion system is to change the velocity, or v, of a spacecraft. Because this is more difficult for more massive spacecraft, designers generally discuss spacecraft performance in amount of change in momentum per unit of propellant consumed also called specific impulse. The higher the specific impulse, the better the efficiency. Ion propulsion engines have high specific impulse (3000 s) and low thrust whereas chemical rockets like monopropellant or bipropellant rocket engines have a low specific impulse (300 s) but high thrust.
The dominant form of chemical propulsion for satellites has historically been hydrazine, however this fuel is highly toxic and at risk of being banned across Europe. Non-toxic 'green' alternatives are now being developed to replace hydrazine. Nitrous oxide-based alternatives are garnering a lot of traction and government support, with development being led by commercial companies Dawn Aerospace, Impulse Space, and Launcher. The first nitrous oxide-based system ever flown in space was by D-Orbit onboard their ION Satellite Carrier (space tug) in 2021, using six Dawn Aerospace B20 thrusters, launched upon a Falcon 9 rocket.
The Glenn Research Center aims to develop primary propulsion technologies which could benefit near and mid-term science missions by reducing cost, mass, and/or travel times. Propulsion architectures of particular interest to the GRC are electric propulsion systems, such as Ion and Hall thrusters. One system combines solar sails, a form of propellantless propulsion which relies on naturally-occurring starlight for propulsion energy, and Hall thrusters. Other propulsion technologies being developed include advanced chemical propulsion and aerocapture.
A variety of hypothetical propulsion techniques have been considered that require a deeper understanding of the properties of space, particularly inertial frames and the vacuum state. To date, such methods are highly speculative and include:
There are many properties of ceramics and glass that make these materials desirable for aerospace applications (including both commercial and defense aircraft and vehicles for space exploration). The most important are lightweight, high temperature resistance, electrical insulation, high energy of ablation, resistance to corrosion, chemical stability, wear resistance, and ability to withstand vibration.
Ceramics find use in aerospace because they are lighter than metals enabling faster speeds, reduced fuel consumption, larger payloads, and longer times in space for exploration vehicles. High temperature resistance allows commercial and military aircraft engines to run hotter, thus reducing CO2 and NOx emissions, and is critical for domes and radomes used in weapon systems that travel under the harshest conditions. Electrical insulation is necessary to avoid electromagnetic interference with the instrumentation aboard and the communication system between the pilot and ground control. High energy of ablation is critical for tiles and armor used to protect re-entry vehicles and objects flying in outer space that come in contact with fragments or particles floating in space, such as meteorites, as well as to protect military planes and helicopters during field missions. Resistance to corrosion and chemical stability are needed to protect parts of the aircraft from contact with corrosive and hazardous materials, such as jet fuel. Wear resistance is important in friction products such as brakes and bearings. In addition, vibrations and associated noise must be kept to a minimum because it creates discomfort for passengers, increases fatigue of the aircraft structural and electronic components, and, in military planes, makes them easier to be detected.
Ceramic-based materials for aerospace applications include oxides (e.g., alumina), non-oxides (e.g., carbides, borides, and nitrides), glass-ceramics, and ceramic matrix composites (e.g., silicon carbide composites). These materials are characterized by dimensional stability over a range of temperatures, and are optimized to have good mechanical strength and chemical resistance. 1e1e36bf2d