Combustion efficiency of iridium coated pellets for environmentally friendly space propulsion

  • Most of the satellite engines still uses critical fuels such as hydrazine, which is chemically aggressive, toxic and carcinogenic. New developments for satellite engines try to avoid such critical propellants. One promising approach is the usage of rocket-grade hydrogen peroxide [H2O2] in mono- and bipropellant driven rocket engines. Catalysts in the rocket engines convert the hydrogen peroxide by an exothermic catalytic reaction; the resulting hot gases oxygen and water vapor provide the thrust. Currently used catalysts are, for example, Al2O3 pellets impregnated with platinum. Within a joint research project of Aschaffenburg University and the German Aerospace Center new catalysts are developed. They consist of ceramic pellets coated with iridium using the magnetron sputtering process. Thereby the surface structure of the iridium layers strongly depends on the used sputtering process conditions [1]. After optimization of the sputtering parameters, it was demonstrated in laboratory experiments that the catalytic effect (measured by the volume of released gas) can be increased by a factor of four compared to platinum impregnated pellets [2]. In first hot firing tests at the test bench complex M11 at the DLR- Institute of Space Propulsion, these new, iridium-based catalysts have been used in a model combustion chamber for hydrogen peroxide decomposition. For this purpose, the reaction chamber was filled with iridium pellets in the high-altitude simulation chamber of the M11.2 test bench. The model chamber was equipped with numerous measuring devices like temperature and pressure sensors (e.g. Tcat, pcat). With the help of the mass flow and the herein obtained data, performance characteristics of the propellant system were accessible. High-concentrated hydrogen peroxide was used in the experiments as monopropellant (~ 87-wt.% H2O2). During the experiments, the combustion chamber was operated in pulse mode and in continuous mode. Aim of this campaign called MoCa (“Monopropellant Catalytic Demonstrator”) is the demonstration of functionality and the performance evaluation of this iridium-based monopropellant system. Recent experimental results will be presented. References: [1] A. Büttner et al., Thin Solid Films 2018, 662: 41–46 [2] M. Stollenwerk et al., Journal of Materials Science 2021, 56(16), 9974-9984
Metadaten
Author:Dominic FreudenmannORCiD, Manfred StollenwerkORCiD, Thorsten DöhringORCiD, Johannes Stadtmüller, Michele NegriORCiD, Felix Lauck
Parent Title (German):14th Pico- and Nanosatellite Workshop, Würzburg, Germany
Document Type:Conference Proceeding
Language:German
Year of Completion:2021
Date of first Publication:2021/09/22
Contributing Corporation:German Aerospace Center (DLR), Hardthausen
Release Date:2021/09/28
GND Keyword:Satellitentechnik; Katalysator; Iridium
Urheberrecht:1
research focus :Materials / Innovative Material Processing
Materials / Material Testing & Sensor Technology
Licence (German):Keine Lizenz - es gilt das deutsche Urheberrecht
Einverstanden ✔
Diese Webseite verwendet technisch erforderliche Session-Cookies. Durch die weitere Nutzung der Webseite stimmen Sie diesem zu. Unsere Datenschutzerklärung finden Sie hier.