The number of rocket launches have increased significantly in the last decade. Rockets are needed for everything from restocking the international space station to launching military and commercial communications satellites. All of these rocket launches are actually contributing to air pollution and atmospheric co2 levels.
The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) and the Brazilian aerospace agency Agência Espacial Brasileira (AEB) have taken a big step forward in the development of a new rocket that is fuelled with oxygen and alcohol. The results presented here of the first burn test series for the upper-stage engine of a future Brazilian small launch vehicle demonstrate this. The tests with two newly designed injection heads were successfully completed in December 2016 within the framework of a German-Brazilian partnership.
Making green rocket fuel
“In order to find the optimum technology for the propulsion of a future German-Brazilian rocket, two injection heads based on different concepts were developed in parallel,” says Lysan Pfützenreuter, project manager at the DLR Space Administration.
In this first series, we have achieved all our major test objectives. A total of 42 ignitions were successfully carried out over a period of 20 days. During these tests, we were able to closely analyse, among other things, the ignition behaviour and stability of the system during ignition and start-up of the thrust chamber. From this we have gained important insights for further engine development.
The tests took place at the P8 test facility of the DLR Institute of Space Propulsion at the Lampoldshausen site between July and December 2016. Specifically, the two injection heads differ in how the fuel is sprayed into the combustion chamber and mixed. One system was developed by the Instituto de Aeronáutica e Espaço (IAE) in Brazil; the other developed and built in Germany by Airbus Safran Launchers as part of the SALSA project (system design of an alcohol LOX propulsion as a substitute for storable fuels).
‘Green’ propellant for better environmental compatibility – Alcohol Rocket Fuel
The injection head is destined to one day be at the core of the new L75 engine, which will propel Brazilian small launch vehicles in the future. What makes this unique is that the new technology makes it possible to use ethanol – ordinary alcohol – as fuel. Ethanol, like methane, is one of the so-called ‘green’ fuels. These are becoming increasingly important as they are more environmentally friendly and have less adverse health effects than the hydrazine compounds generally used for space travel. In addition to these positive effects, these ‘new’ fuels can also significantly reduce the cost of space travel, since the cost for safe storage and handling of these substances is significantly lower than that for hydrazine. In Europe, how long hydrazine will continue to be approved as a fuel under the REACH regulation (Registration, Evaluation, Authorization and Restriction of Chemicals) is questionable. This European Union regulation has been controlling the authorisation and use of chemical substances since it came into force in 2007.
Thrust chamber tests with ethanol for orbital rockets only possible at Lampoldshausen
In Europe, there is only one facility for testing engine components for orbital rockets – i.e. rockets that can transport a payload into orbit – with ethanol fuel: the P8 test facility at the DLR site in Lampoldshausen. “The test facility had already been extended with a high-pressure ethanol supply in the spring of 2016. This means that another ‘green’ fuel is available on the P8 alongside the existing oxygen, hydrogen and methane fuels,” says Jan Alting, SALSA project manager at Airbus Safran Launchers GmbH. “For Europe, the P8 covers almost the entire range of the current fuel combinations of interest for the technology development and thrust chamber testing for launchers.”
German-Brazilian cooperation on engine development
The burn test series is part of a German-Brazilian partnership that was initiated in 2011 between the German Aerospace Center and the Brazilian space agency Agência Espacial Brasileira (AEB). It focuses on cooperation in the areas of engine development, high-altitude research rockets and research into weightlessness. The L75 engine and one of the two injection heads was developed, built and financed by the Instituto de Aeronáutica e Espaço in Brazil.
The planning, execution and evaluation of the test series, as well as the production of the second injection head, were coordinated by Airbus Safran Launchers GmbH on behalf of the DLR Space Administration and carried out with funding from the German Federal Ministry for Economic Affairs and Energy (BMWi).
About Gordon Smith Gordon's expertise in the area of industrial energy efficiency and alternative energy. He is an experienced electrical engineer with a Masters degree in Alternative Energy technology. He is the co-founder of several renewable energy media sites including Solar Thermal Magazine.