September 29, 2016

Research on 'green' rocket propellants – symposium with experts from science and industry at DLR in Lampoldshausen

The researchers at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) Lampoldshausen site can look back on over 50 years of applied research at the M11 test facility. DLR's M11 test complex was built in the 1960s, and since then has been available for research and development in the area of rocket and ramjet engines. But this year's symposium, attended by around 40 guests from science, industry and the ESA - European Space Agency (ESA) ins on 23 September at the test and research centre for rocket engines in Lampoldshausen, cast a light on more than just the past; it focused on the propellants of the future and the milestones for their development.

Future rocket propellants will need to be environment-friendly, inexpensive and easy to handle. At the same time, they will need to exhibit comparable or even better performance in order to replace conventional propellants such as hydrazine. These are storable for long periods of time, and the engines that use them work reliably in a space environment over extended mission durations. However, they have the disadvantage of being toxic. As a result, handling these substances on the ground, especially during transport, fuelling and launch preparations, is extremely complex and expensive.

In a total of 12 technical presentations, experts discussed sustainable concepts in the area of environment-friendly propellants. Stefan Schlechtriem, Director of the DLR Institute of Space Propulsion, believes that the development, manufacture and testing of advanced propellants present a major challenge for the entire space industry: "Today, we must start addressing the task of using our expertise, our test facilities and our laboratories in a targeted manner to develop advanced, environment-friendly propellants. Here, efficient scientific and industrially-oriented collaboration will play an important role."

Advanced 'green' propellants are becoming increasingly important

The DLR Institute of Space Propulsion is intensively studying innovative propellants, for instance within the EU Horizon 2020 programme Reform. This project focuses on further developing propellants based on ammonium dinitramide (ADN). These propellants are substantially less harmful to humans and the environment, while also delivering higher performance. DLR researchers in Lampoldshausen are pooling their expertise with partners for the development, analysis, evaluation and testing of these propellants. The manufacturing process for these less toxic but more powerful propellants is extremely complex, and little testing has been conducted so far on their use in the space industry. Seeking to break new ground, DLR is therefore conducting research on the entire process, from the development and manufacture of these advanced propellants through to their testing. In addition, the research team is using physical-chemical laboratory methods to determine the properties of the propellants, such as their density, viscosity and impurities. The combustion, ignition, injection and delivery behaviour of the innovative propellants are then examined in the M11 test facility. Here, modern measurement and control systems provide information on the behaviour of propellants under experimental conditions. The deployment of state-of-the-art measurement technology such as high-speed cameras, as well as high-resolution pressure, temperature and thrust sensors, enables a targeted analysis of the propellants, injectors and combustion chambers. In addition, DLR researchers install optical combustion chambers in the test facility to enable visual analysis of the combustion process, and are hence able to detect and subsequently evaluate the thermal loads that occur.

The M11 test facility at the Lampoldshausen site

The equipment and structure of the M11 test facility have undergone development since its inauguration in 1966. Over recent decades, DLR scientists have conducted extensive research and technology development work that has yielded detailed insight into the flow, ignition and combustion processes taking place in model combustion chambers, and have also determined the physical and chemical properties of a wide range of propellants, especially hybrid and gelled propellants. With approximately 20 employees, the team in the Propellant Department at the DLR Institute of Space Propulsion are involved in a number of research projects investigating gelled and environment-friendly propellants, hybrid engines and scramjets. They are therefore an important partner for industry, institutions and research facilities in Europe and worldwide.


Anja Kaboth

Corporate Communications Lampoldshausen
German Aerospace Center (DLR)
Corporate Communications
Im Langen Grund, 74239 Hardthausen
Tel: +49 6298 28-201

Dr.-Ing. Helmut Ciezki

Propellant Department
German Aerospace Center (DLR)
Institute of Space Propulsion
Im Langen Grund, 74239 Hardthausen