Three-dimensional, additive printing has emerged as an exciting new technology for the design and manufacture of small spacecraft systems. Using 3-D printed thermoplastic materials, hybrid rocket fuel grains can be printed with nearly any cross-sectional shape, and embedded cavities are easily achieved. Applying this technology to print fuel materials directly into a CubeSat frame results in an efficient, cost-effective alternative to existing CubeSat propulsion systems. Different 3-D printed materials and geometries were evaluated for their performance as propellants and as structural elements. Prototype "thrust columns" with embedded fuel ports were printed from a combination of acrylonitrile utadiene styrene (ABS) and VeroClear, a photopolymer substitute for acrylic. Gaseous oxygen was used as the oxidizer for hot-fire testing of prototype thrusters in ambient and vacuum conditions. Hot-fire testing in ambient and vacuum conditions on nine test articles with a combined total of 25 s burn time demonstrated performance repeatability. Vacuum specific impulse was measured at over 167 s and maximum thrust of individual thrust columns at 9.5 N. The expected ΔV to be provided by the four thrust columns of the consumable structure is approximately 37 m/s. With further development and testing, it is expected that the consumable structure has the potential to provide a much-needed propulsive solution within the CubeSat community with further applications for other small satellites.

<p>ABSTRACT</p><p>Allergy to mustard has been reported for many years, in some cases as severe anaphylactic reactions. Recent studies imply that this allergy is increasing. Three major allergens have been isolated and characterised; Sin a 1 and Sin a 2 in yellow mustard (Sinapis alba), and Bra j 1 in oriental mustard (Brassica juncea). Yellow mustard and black mustard (Brassica nigra) are the most common species in Europe, whereas oriental mustard is more frequent outside Europe. Mustard plants belong to the Brassicaceae/Cruciferae family. Mustard is present as an ingredient in different foods, sauces and spices, often in small amounts. According to the European labelling directives, mustard and products thereof must always be declared. To monitor this regulation, methods need to be developed to detect mustard. Polyclonal antibodies, produced in rabbits, against yellow and black mustard were characterised with immunodiffusion, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing conditions, and immunoblotting. Rocket-immunoelectrophoresis and enzyme-linked immunosorbent assay (ELISA) were developed for the detection and quantification of mustard protein. With indirect competitive ELISA a concentration of 156ng mustard protein per ml food extract was detected, which is more than enough to cover the lowest reported reactive doses.</p>

ABSTRACT Allergy to mustard has been reported for many years, in some cases as severe anaphylactic reactions. Recent studies imply that this allergy is increasing. Three major allergens have been isolated and characterised; Sin a 1 and Sin a 2 in yellow mustard (Sinapis alba), and Bra j 1 in oriental mustard (Brassica juncea). Yellow mustard and black mustard (Brassica nigra) are the most common species in Europe, whereas oriental mustard is more frequent outside Europe. Mustard plants belong to the Brassicaceae/Cruciferae family. Mustard is present as an ingredient in different foods, sauces and spices, often in small amounts. According to the European labelling directives, mustard and products thereof must always be declared. To monitor this regulation, methods need to be developed to detect mustard. Polyclonal antibodies, produced in rabbits, against yellow and black mustard were characterised with immunodiffusion, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing conditions, and immunoblotting. Rocket-immunoelectrophoresis and enzyme-linked immunosorbent assay (ELISA) were developed for the detection and quantification of mustard protein. With indirect competitive ELISA a concentration of 156ng mustard protein per ml food extract was detected, which is more than enough to cover the lowest reported reactive doses.

Propellants based on hydroxylammonium nitrate (HAN) have shown promise as a hydrazine replacement because of their comparably low toxicity, low vapor pressure, high specific impulse and high density. Herein, the recent history of advanced monopropellant research is explored, and new experimental techniques are presented to investigate the combustion behavior of a potential hydrazine replacement propellant. Nitromethane, a widely available monopropellant with a recent resurgence in research, is utilized in the current study as a proof of concept for the newly designed equipment and as a step towards investigating more-advanced, HAN-based monopropellants. A strand bomb facility capable of supporting testing at up to 340 atm was employed, and experiments were performed between 28 atm and 130 atm. Burning rate data for nitromethane are calculated from experiments and a power correlation is established as r(mm/s) = 0.33[P(MPa)]^1.02. A comparison with available literature reveals this correlation to be very much in agreement to other studies of nitromethane. Other physical characteristics of nitromethane combustion are presented. Updates to the facility and new methods to examine the combustion of liquid propellant are described in detail. Special focus is given to procedures and safety information.

The prediction of transient phenomena inside Liquid Rocket Engines (LREs) has not been feasible until now because of the many challenges posed by the operating conditions inside the combustion chamber. Especially, the departure from ideal gas because of the cryogenic injection in a high-pressure chamber is one of the ma jor hurdle for such simula- tions. In order to begin addressing these issue, a real-gas model has been implemented in a massively parallel flow solver. This solver is capable of performing Large-Eddy Simula- tions (LES) in geometrical configurations ranging from an axisymmetric slice to a 3D slice up to a full 3D combustor. We present here the results from an investigation of unsteady combustion inside a small-scale, multi-injectors LRE. Both thermally perfect gas (TPG) and real gas (RG) approaches are evaluated for this LOX-GH2 system. The Peng-Robinson cubic equation of state (PR EoS) is used to account for real gas effects associated with the injection of cryogenic oxygen. Realistic transport properties are computed but simplified chemistry is used in order to achieve a reasonable turnaround time. Results show the impor- tance of the unsteady dynamics of the flow, especially the interaction between the different injectors. The role of the equation of state is assessed and the real gas model, despite a limited zone of application, seems to have a strong influence on the overall chamber behav- ior. Although several features in the simulated results agree well with past experimental observations, the prediction of heat flux using a simplified flux boundary condition is not completely satisfactory. This work also reviews in details the state of our knowledge on supercritical combustion in a coaxial injector configuration, stressing issues where numeri- cal modeling could provide new insights. However, many developments and improvements are required before an LES modeling of such a flow is both feasible and valid. We finally propose a comprehensive roadmap towards the completion of this goal and the possible use of CFD as a design tool for a modern liquid rocket engine.

There exists wide ranging research interest in high-energy-density matter (HEDM) propellants as a potential replacement for existing industry standard fuels for liquid rocket engines. The U.S. Air Force Research Laboratory, the U.S. Army Research Lab, the NASA Marshall Space Flight Center, and the NASA Glenn Research Center each either recently concluded or currently has ongoing programs in the synthesis and development of these potential new propellants. In order to perform conceptual designs using these new propellants, most conceptual rocket engine powerhead design tools (e.g. NPSS, ROCETS, and REDTOP-2) require several thermophysical properties of a given propellant over a wide range of temperature and pressure. These properties include enthalpy, entropy, density, viscosity, and thermal conductivity. Very little thermophysical property data exists for most of these potential new HEDM propellants. Experimental testing of these properties is both expensive and time consuming and is impractical in a conceptual vehicle design environment. A new technique for determining these thermophysical properties of potential new rocket engine propellants is presented. The technique uses a combination of three different computational methods to determine these properties. Quantum mechanics and molecular dynamics are used to model new propellants at a molecular level in order to calculate density, enthalpy, and entropy. Additivity methods are used to calculate the kinematic viscosity and thermal conductivity of new propellants. This new technique is validated via a series of verification experiments of HEDM compounds. Results are provided for two HEDM propellants: quadricyclane and 2-azido-N, N-dimethylethanamine (DMAZ). In each case, the new technique does a better job than the best current computational methods at accurately matching the experimental data of the HEDM compounds of interest. A case study is provided to help quantify the vehicle level impacts of using HEDM propellants. The case study consists of the National Aeronautics and Space Administrations (NASA) Exploration Systems Architecture Study (ESAS) Lunar Surface Access Module (LSAM). The results of this study show that the use of HEDM propellants instead of hypergolic propellants can lower the gross weight of the LSAM and may be an attractive alternative to the current baseline hypergolic propellant choice.

This work was motivated by questions raised from multifrequency microwave interferometer measurements taken in a cylindrical plasma on the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) project. Standard data analysis based on a thin beam model neglecting refraction yields inconsistent electron densities and density profiles for different frequencies. This work focuses on the development of a model for the wave propagation through cylindrical plasmas when the plasma radius is on the order of the beam waist. For the calculations presented a Gaussian beam profile and plasma spatial profile were assumed. Both refraction by density gradients and finite beam sizes are found to play important roles and explain polychromatic differences in the electron densities and profiles. Calculations for the new model are compared to a thin beam model not accounting for refraction and experimental data from VASIMR.

No description available.

The manufacturing process for solventless extruded double base propellants involves a number of rolling and reworking stages. Throughout these processes a decrease in weight average molecular weight was observed, this was attributed to denitration. Differential scanning calorimetery data indicated that the reworking stages of extruded double base propellant manufacture were crucial to the homogenisation of the propellant mixture. To determine the homogeneity of the final extruded product, a sample was analysed across its diameter. No variations in stabiliser concentration, molecular weight, or Vickers hardness were detected. An accelerated thermal ageing trial simulating up to 8 years of ageing at 25°C was carried out to evaluate the storage characteristics. Reductions in stabiliser concentration, number average molecular weight, weight average molecular weight and polydispersity compared with un-aged samples were observed. The glass transition temperature measured using differential scanning calorimetery decreased by ~3°C. The decrease was attributed to the initial denitration reducing the energy of bond rotation and shortening the polymer chains, both factors reducing the energy required for movement. Modulus values determined from dynamic mechanical analysis temperature scanning experiments, did not detect significant variation between un-aged and aged samples. Though it was considered that variations would be likely if a more extensive ageing program was completed. In order to evaluate propellant behaviour at very high and low frequencies, time temperature superposition (TTS) and creep testing were carried out. The TTS technique superpositioned data well, allowing future investigation of high frequency propellant properties. Creep testing was considered to be an appropriate approach, though the equipment available was not optimised for such testing. This thesis is concerned with understanding how propellants are manufactured from nitrocellulose, nitroglycerine and other constituents. It is also about how the propellants decompose during long periods of time in storage, and how these changes can be measured using thermal and mechanical methods. It is about how the physical, chemical and thermal properties of the propellant composition change throughout the manufacture. This is relevant as it could be used to develop more efficient manufacturing processes, allow operators to adjust processes to tailor product properties or be used to re-design manufacturing to compensate for a different starting material. The thesis also considers how and why the properties of the product change over the course of years of storage. A specific focus on whether changes in mechanical and thermal properties occur, and if so how they can be detected.

This thesis examines the effects of nanoparticle, metal-oxide additives on the burning rate of composite solid propellants. Recent advancements in chemical synthesis techniques have allowed for the production of improved solid rocket propellant nano-scale additives. These additives show larger burning rate increases in composite propellants compared to previous additive generations. In addition to improving additive effectiveness, novel synthesis methods can improve manufacturability, reduce safety risks, and maximize energy efficiency of nano-scale burning rate enhancers. Several different nano-sized additives, each titania-based, were tested and compared for the same baseline AP/HTPB formulas and AP size distributions. The various methods demonstrate the evolution in our methods from spray-dried powders to pre-mixing the additive in the HTPB binder, and finally to a method of producing the additive directly in the binder as a nano-assembly. Burning rate increases as high as 80% at additive mass loadings of less than 0.5% were seen in non-aluminized, ammonium perchlorate-based propellants over the pressure spectrum of 500 psi (3.5 MPa) to 2250 psi (15.5 MPa). Increases in burning rate up to 73% were seen in similarly formulated aluminized propellants. During the past several years, the research team has refined laboratory-scale techniques for quickly and reliably assessing the mixing and performance of composite propellants with catalytic nanoparticle additives. This thesis also documents some of the details related to repeatability, accuracy, and realism of the methods used in the team’s recent nano-additive research; it also introduces the latest techniques for producing propellants with nano-sized additives and provides new burning rate results for the entire scope of additives and mixing methods. Details on the propellant characterization methods with regard to physical and combustion properties are provided. Snapshots from atmospheric propellant combustion videos taken with a Photron FASTCAM SA3 high-speed camera are included along with existing pressure and light-emission responses.