Yann Batonneau

Development and Test of a Miniature Hydrogen Peroxide Monopropellant Thruster

Analysis of present and future missions concluded that a miniaturised hydrogen peroxide monopropellant rocket engine is the optimum solution for the increasing demand for small and low cost propulsion systems for small satellites. The attractiveness of monopropellant thrusters is based on its operational and structural simplicity. Additionally, the utilization of hydrogen peroxide as propellant instead of hydrazine allows the reduction of the overall costs and would qualify such a system as a green propellant propulsion system. The present paper describes the development of a monopropellant thruster utilizing hydrogen peroxide and advanced catalyst beds. The utilization of a monolithic catalyst reduces the pressure loss across the catalyst bed significantly compared to formerly used pellet or gauze catalyst. This allows the use of relative lightweight tank and significantly minimizes the total weight. For Two different catalyst materials have been developed to achieve optimized decomposition. The present paper summarizes the experimental evaluation of the catalysts. Decomposition temperatures of up to 670°C and decomposition efficiencies up to 99% have been achieved. Up to 1.2 kg of hydrogen peroxide has been decomposed by a single catalyst, corresponding to about 1.25 hrs of operation. This is estimated to correspond in vacuum condition to a total delivered total impulse of 1600 Ns. A thrust balance was designed and built. Preliminary thrust measurements under atmospheric conditions have shown that the laboratory model can generate thrust in a range of at least 50 to 550 mN.

Influence of the fuel on the thermal and catalytic decompositions of ionic liquid monopropellants

Binary aqueous mixtures of HAN, AN, ADN and HNF have been prepared. Two series of ternary mixtures have been synthesized with methanol and glycerol as fuels: one series with fuel excess and a second series with stoichiometric fuel content. Thermal decomposition of the solutions prepared has been analyzed. For binary HAN, HNF and ADN aqueous solutions, the thermal decomposition starts only once water has been fully vaporized and the oxidizer is in the liquid state. In the case of ammonium nitrate we do not observe any exothermic decomposition, but only the vaporization and dissociation of the liquid compound into ammonia and nitric acid. The influence of the fuel depends strongly on the oxidizer. Methanol is vaporized before the decomposition, leading to results close to those observed for binary mixtures. HAN-based solutions display the highest catalytic effect with a temperature decrease of about 100 °C. ADN-based propellants display the highest decomposition rates, but the catalytic effect remains weak. Catalytic decomposition of HNF leads to a two-step mechanism with slow decomposition rates. The ability order to oxidize completely glycerol in stoichiometric mixtures is: HAN < HNF < ADN

Monolithic catalysts for the decomposition of energetic compounds

Abstract Pellet-based catalysts have been developed more than 60 years ago for the decomposition of hydrogen peroxide and hydrazine for propulsion applications. Cellular ceramic supports are now proposed to replace such catalyst support for monopropellant decomposition or bipropellant ignition. Different honeycomb supports have been manufactured by CTI Company and used as catalyst support for lab-scale reactor as well as for full-scale application. The support parameters are the chemical nature (cordierite, mullite, mullite–zircone, SiC…), the channel shape and density. For full-scale reactors, dedicated apparatus have been developed to control the key parameters during the preparation of the catalysts: quality and homogeneity of the wash-coating layer, impregnation conditions to reach a high loading level of active phase.

Test of a Turbo-Pump Fed Miniature Rocket Engine

The increasing application of microsatellites (from 10 kg up to 100 kg) for a rising number of various missions requires the development of suitable propulsion systems. Microsatellites have special requirements for a propulsion system such as small mass, reduced volume, and very stringent electrical power constraints. Existing propulsion systems often can not satisfy these requirements. The present paper discusses the development and test of a bipropellant thruster complying with these requirements. The main development goal of this effort was the utilization of ethanol in combination with hydrogen peroxide (H2O2) as a non-toxic propellant combination. The Turbo-Pump Fed Miniature Rocket Engine (TPF-MRE) is a bipropellant thruster consisting of four subsystems: the propellant pumps, a decomposition chamber with a monolithic catalyst, a turbine, and the thruster itself. The turbine is driven by the decomposed hydrogen peroxide and magnetically coupled with a power generator. The power produced is then used to generate a pressure head in order to deliver the propellant into the combustion chamber. This system therefore constitutes a self-sustaining system and does not rely on the limited power supply of a micro-satellite. Previous test have shown that although the thruster can be operated with ethanol and oxygen, it was not possible to ignite the thruster when utilizing hydrogen peroxide in a 70% concentration by weight. A minor redesign of the thruster and the test facility was therefore initiated. This redesign together with the use of hydrogen peroxide in higher concentration was speculated to improve this behavior. However, even though the monolithic catalysts were able to decompose hydrogen peroxide in a concentration of 87.5 % with nearly 100 % efficiency, it was not possible to ignite or operate the thruster. Subsequently, a thorough investigation of the baseline design and operational conditions of the thruster was conduced. It was found that the failure of the thruster to ignite is due to a combination of reasons. The combustion chamber length is too short to facilitate sufficient mixing of the propellants, making an ignition impossible or very difficult at least. Additionally, the combustion chamber pressure which was chosen such that it accommodates the performance of commercially available mircopumps is considered too low. This further deteriorates the conditions for which an ignition is feasible.

Catalytic decomposition of energetic compounds - Influence of catalyst shape and ceramic substrate

Catalytic decomposition of energetic compounds is used for different purposes like propulsion application (launcher, satellites and missiles) and gas generator (e.g. rescue systems). The energetic liquids (H 2O2, N 2H4, ionic liquids, N 2O, …) are decomposed on catalytic beds which must present very good thermal and mechanical properties to resist frequent thermal shocks and high flow rates. Compared to conventional alumina-based supports developed specifically for this application about 30 years ago (extrudates, pellets, spheres), honeycomb monolith catalysts show many advantages: (i) lower pressure drop, (ii) better thermal shock and attrition resistance, (iii) uniform flow distribution and mass/heat transfer conditions, (iv) shorter diffusion length, and (v) large heritage from cleaning of car exhaust gases. Therefore, monolithic reactors represent very attractive alternatives to traditional systems with the future ability to develop chemical micro-propulsion systems. These new monolith applications demand a careful control of the substrate chemical nature, the surface impregnation by the thin porous wash-coat layer and the impregnation of this layer by the active phase precursor. An overview is given and two applications to the decomposition of hydrogen peroxide and ionic liquid solutions are presented and discussed.

Chemical micropropulsion. State of the art and catalyst surface requirements.

Different propellant types (solid, cold and hot gas, liquid) proposed for micropropulsion systems are reviewed. Liquid-substrate surface interactions are discussed, focusing on surface tension, viscosity and contact angle. A comparison between molecular and ionic liquids is presented and their relationship to microfluidics. The use of hydrophobic or superhydrophobic surface is of interest for microchanneled devices by decreasing the pressure drop. Such surfaces could be developed inside honeycomb monolith and the channel size could be tuned in the submillimeter range by finely controlling the washcoat procedure. Any further development of this field needs microfluidics data. An ideal set-up for a chemical, catalytic microthruster based on a single monolithic channel is proposed.

Assessment of Catalysts for Hydrogen-Peroxide-Based Thrusters in a Flow Reactor

Hydrogen peroxide is a candidate propellant for rocket-propulsion applications with the potential to replace highly toxic propellants currently used. Decomposition of hydrogen peroxide yields a high-temperature oxygen-steam mixture, which can be used as monopropellant or as oxidizer in a bipropellant configuration. This work examines different types of cellular ceramic-based catalysts for hydrogen-peroxide decomposition at miniature scale of nominal mass flows of 0.3  g s−1. An exhaustive investigation of different catalysts in a flow reactor configuration similar to a propulsion application is conducted. The test matrix includes honeycomb monoliths with different channel geometries, densities, lengths, different carrier materials, and wash-coating procedures, as well as different types of catalysts such as pellets and foams. Thirty nine catalyst configurations with a total of 121 catalysts have been experimentally investigated based on their transient and stationary performance at design mass-flow levels...

Improvement of catalytic decomposition of ammonium nitrate with new bimetallic catalysts

Ammonium nitrate NH 4NO 3 (AN) is a proposed candidate for energetic ionic l iquids and solid propellants. The decomposition of aqueous NH 4NO 3 (50-55 wt-%), in the thermal condition and in the presence of various mono- and bimetallic catalysts, was investigated using thermal analysis (DTA-TGA), batch reactor and dynamic flow reactor with on-line MS analysis. The first results are as follows: heat ing in the absence of catalyst shows the quantitative only endothermic vaporization of water and AN have been evidenced into ammonia and nitric acid even at high temperature. In the presence of catalysts, a dramatic change is observed. All monometallic catalysts (sup ported Pt, Fe, Cu or Zn) present a true catalytic decomposition reaction linked to exothermic peaks. However, only Pt-based catalyst was able to trigger the decomposition at l ower temperature (210 °C). Nevertheless, tests in batch reactor reveals mediocre results ass ociated to very slow AN decomposition. Bimetallic catalysts M-M’/Al 2O3-Si (M, M’ = Fe, Cu, Zn, Pt) have been evaluated to o. The catalytic decomposition depends on the active phase and on the preparation method of the bimetallic catalysts. The addition of zinc or coppe r on non-reduced platinum catalyst (PtCuAl-NR and PtZnAl-NR) increases the catalytic effect of platinum and the results display a beneficial effect disclosed by a violent one-step decomposition. On the contrary, the addition of zinc or copper on reduced platinum metal leads to less active catalysts and the decomposition occurs in two steps. This activity di fference could be mainly related to the formation zinc-platinum and copper-platinum alloys when adding the second metallic precursor on non-reduced platinum, followed by a final reduction. Whatever the catalyst (PtAl, PtCuAl-NR or PtZnAl-NR), the results obtained using a dynamic reactor reveal the presence of the same gaseous and condensed products: major nitrogen and nitric acid and no oxygen; the formation of nitrogen oxides NO and N 2O depends on the catalyst nature: minor for PtAl and medium for PtCuAl-NR and PtZnAl-NR.

PRECISE - development of a MEMS- based monopropellant micro Chemical Propulsion System

PRECISE focuses on the research and development of a MEMS-based monopropellant micro Chemical Propulsion System (μCPS) for highly accurate attitude control of satellites. The availability of μCPS forms the basis for defining new mission concepts such as formation flying, advanced robotic missions and rendezvous maneuvers. These concepts require propulsion systems for precise attitude and orbit control maneuverability. Basic research will be conducted aiming at improving crucial MEMS technologies required for the propulsion system. Research and development will also focus on the efficiency and reliability of critical system components. System analysis tools will be enhanced to complement the development stages. In addition, application-oriented aspects will be addressed by two endusers who are planning a formation flying mission for which the propulsion system is crucial. Finally, the μCPS will be tested in a simulated space vacuum environment. These experiments will deliver data for the validation of the numerical models.

PRECISE - preliminary results of the MEMS-based µCPS

This paper gives an overview on preliminary results of the project PRECISE. PRECISE focuses on the research and development of a MEMS-based monopropellant micro Chemical Propulsion System (μCPS) for highly accurate attitude control of satellites. Space mission concepts like formation flying, advanced robotic missions and rendezvous maneuvers require propulsion systems for precise attitude and orbit control maneuverability. Within PRECISE, research is conducted aiming at improving crucial MEMS technologies required for the propulsion system. Research and development also focuses on the efficiency and reliability of critical system components. Currently, the individual components of the prototype are being manufactured and assembled. The diagnostic tools for the plume and the thrust measurements are assembled and ready to be tested. The preparations for the final hot firing tests have started. Finally, the μCPS prototype will be tested in a simulated space vacuum environment. These experiments will deliver data for the validation of the numerical models implemented in the DLR TAU CFD code.