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This paper presents the initial development and characterization of a novel micropropulsion system for nanosatellite applications: a liquid-fed pulsed plasma thruster (LF-PPT) comprising a Lorentz-...

Electric solid propellants are advanced solid chemical rocket propellants controlled by electric current. An electric solid propellant may also be used in an electric propulsion system: specificall...

A novel thruster concept for CubeSats and other small satellites using hydrogen peroxide vapor as a propellant is presented and evaluated. This concept leads to the highest theoretical vacuum speci...

Green liquid monopropellant thrusters provide an alternative to toxic hydrazine. A premixed liquid monopropellant based on hydrogen peroxide with ethanol blending was suggested to replace hydrazine...

This Paper suggests two speculations on the nontoxic hypergolic propulsion using hydrogen peroxide as an oxidizer based on the experimental data. Drop tests were repeatedly performed with the nonto...

Hydroxylammonium-nitrate-based monopropellant thrusters have been continuously researched as a replacement for conventional hydrazine thrusters. An ignition system using the discharge plasma of nob...

A number of platinum catalysts for the decomposition of 98% hydrogen peroxide, based on different substrates, geometries, and sizes, have been prepared using different procedures. The catalysts have undergone a set of dedicated tests for screening their catalytic activity and their thermomechanical resistance in order to identify the most efficient and suitable catalyst to be used for a pulsed monopropellant propulsion system. An experimental test campaign on a 20 N monopropellant thruster prototype has been carried out with the aim of assessing the capability of the finally selected new Pt/α-Al2O3 catalysts of effectively decomposing 98% hydrogen peroxide and the attainable propulsive performance in steady-state conditions for the future assessment of the propulsive performance of the intrinsically unsteady new propulsion concept. The catalysts have been able to decompose up to 1 liter of 98% H2O2 with very good efficiencies (hc*>95% and hΔT≥90%) and without any pellet breakage or catalytic degradation. ...

Imidazole-based ionic liquids are investigated in terms of dual-mode chemical monopropellant and electrospray rocket propulsion capabilities. A literature review of ionic liquid physical properties is conducted to determine an initial, representative set of ionic liquids that shows favorable physical properties for both modes, followed by numerical and analytical performance simulations. The ionic liquids 1-butyl-3-methylimidazolium dicyanamide, 1-butyl-3-methylimidazolium nitrate, and 1-ethyl-3-methylimidazolium ethyl sulfate meet or exceed the storability properties of hydrazine, and their electrochemical properties indicate that they may be capable of electrospray emission in the purely ionic regime. These liquids are projected to have 13–23% reduced monopropellant propulsion performance in comparison to hydrazine due to the prediction of solid carbon formation in the exhaust. The use of these ionic liquids as a fuel component in a binary monopropellant mixture with hydroxylammonium nitrate shows a 1–4...

Potential dual-mode monopropellant/electrospray-capable mixtures of hydroxylammonium nitrate with ionic liquid fuels [Bmim][NO3] and [Emim][EtSO4] are synthesized and tested for catalytic decomposition in a microreactor setup. The setup is benchmarked using a 30% hydrogen peroxide solution decomposed via silver catalyst. Results show similar trends but with variance in the quantitative data obtained in the literature. This was found to be a direct result of the sample-holder geometry. Hydrazine decomposition was conducted on an unsupported iridium catalyst. The same trends in terms of pressure-rise rate during decomposition (∼160 mbar/s) are obtained with unsupported catalyst but at 100 °C instead of room temperature for tests conducted on supported catalysts in the literature. For the [Bmim][NO3]/hydroxylammonium nitrate propellant, rhenium catalyst preheated to 160 °C yielded a pressure-rise rate of 26 mbar/s, compared to 14 mbar/s for iridium catalyst and 12 mbar/s for no catalyst at the same tempe...

Analytical and numerical investigations of the performance of a series of potential dual-mode propulsion systems using ionic liquids are presented. A comparison of the predicted specific impulse of ionic liquids with hydrazine and unsymmetrical dimethylhydrazine shows that ionic liquid fuels have a 3–12% lower specific impulse when paired with a nitrogen tetroxide oxidizer. However, when paired with hydroxylammonium nitrate oxidizer, the specific impulse of the ionic liquids is 1–4% lower than that of hydrazine and unsymmetrical dimethylhydrazine paired with nitrogen tetroxide. Analytical investigation of an electrospray electric propulsion system shows that ion extraction in the pure ion regime provides a very high specific impulse, outside the optimum range for potential missions. Results suggest a deceleration grid, a lower ion fraction, or emission of higher solvated states is required. Analysis of a dualmode ionic-liquid-propelled spacecraft shows that the electric propulsion component determines the overall feasibility comparedwith current technology. Results indicate that the specific power for an ionic liquid electrospray systemmust be at least 15 W=kg in order for a dual-mode ionic liquid system to compete with traditional hydrazine and Hall thruster technology.

The toxicity of pure hydrazine has prompted the research of possible "green propellants" to replace this mono-propellant for small thruster use. To fulfill this objective, a constant volume computerized batch reactor has been developed, which permits study of different monopropellants and their associated catalysts. This reactor can be used as a screening reactor, and its main advantages are easy use, fast change of catalyst or propellant, very limited consumption of propellant or catalyst, and simultaneous recording of reactor pressure, catalyst, and gas-phase temperatures. The catalyst can be preheated, and the working pressure is between vacuum and 2 bars. The main parameters that can be obtained for the catalyst evaluation are the catalytic decomposition rate, the ignition delay, and the onset decomposition temperature. Three propellants have been checked: pure hydrazine, hydrogen peroxide, and a hydroxylammonium nitrate-(HAN-)triethanolammonium nitrate-(TEAN-) water mixture; they display similar rates and ignition delays but the HAN-based propellant needs higher initial temperature and leads to the simultaneous formation of condensed products at low temperature. For a specific propellant, the results lead to a classification of different catalytic beds before further investigations in dynamic reactors using real working conditions.

The combustion characteristics and reaction mechanism of a HAN-based liquid monopropellant (HANGLY26, consisting of 60% HAN, 14% glycine, and 26% water by weight ) were investigated. Combustion tests of liquid strands formed in test tubes were performed in an optically accessible strand burner. Fine-wire thermocouples were also installed in the strand to measure the temperature distribution of the reaction zone. The burning rate of HANGLY26 exhibited four burning rate regimes for pressures ranging from 1.5 to 18.2 MPa. No luminous e ame was observed in any combustion tests. The temperatures of combustion products in the test tube were found to be near the water boiling points at pressures below 8.8 MPa. For pressures above 8.8 MPa, the product temperatures were found to be lower than the boiling points of water. Slope break points for burning rate vs pressure were found to coincide with those of concentration curves of recovered residues vs pressure. The observed slope breaks in burning rates are shown to be associated with the reaction mechanism changes between adjacent pressure regimes. Major species detected from the recovered liquid residues are nitrogen, nitric oxide, carbon dioxide, and formaldehyde. The pyrolysis of the fresh unburned liquid propellant was also studied. The results were compared with those of the recovered liquid residues.

A new type of propellant, a mixture of ammonium nitrate and alcohol, was examined in ballistic experiments. Withprilledammoniumnitrateandethanol,increasedballisticperformancewasobtainedforthemaximumenergy release conditions. From the measured chamber pressures and measured in-tube velocity proe le, the location of energy release and pressure wave motions are documented. This propellant is characterized by low-product molecular mass, high-specie c energy, and high e exibility in controlling its performance both by changing the type of alcohol and by varying the reactants’ molar ratio.

A high-speed photographic study has been performed of the rapid deformation of ammonium dinitramide (ADN) and glycidyl azide polymer (GAP) by drop-weight impact. ADN was found to be more sensitive than ammonium perchlorate. Both materials have been suggested as potentially useful oxidizers in explosive and propellant applications. ADN was also found to be sensitized by both hard high-melting point grits (60-mm borosilicate or Pyrext glass) and brittle polymers. High-density polyethylene was found to suppress de agration in this material. Heat-sensitive Ž lm was used to conŽ rm that the events seen using high-speed photography were indeed de agrations. GAP was found to be insensitive when impacted in this apparatus, even in the presence of additives or gas bubbles.