Mod­ern rock­et en­gine de­vel­op­ment at a his­toric space fa­cil­i­ty

Test stands keep pace with the times – DLR's Lam­pold­shausen site turns 60

Anyone who visits the DLR site Lampoldshausen is setting foot in one of the most important places in European space history. The 51-hectare site is a hub of modern engine development with strong historical connections. In 1959, the space pioneer Eugen Sänger established a research institute in the Harthausen Forest. Sixty years after its inception, it still bears the traces of its history, while offering tantalising glimpses of the future. Even if some of the test stands at the Institute of Space Propulsion located here exhibit some patina, they have not become worn out. More versatile than ever before, they are well prepared for the new requirements of European space transport systems. In the visitor centre, a group of fascinated guests is marvelling at the enormous Vulcain-2 engine, which hangs from the ceiling like an oversized lamp. This is just one of the numerous rocket propulsion systems tested by the DLR team in Lampoldshausen. As the visitors turn around, they see a wall of images showing the history of the site. But they will have to walk a few metres to learn about its establishment.

The early days – 1959

Eugen Sänger could justifiably feel more than satisfied when spontaneous applause broke out in Lampoldshausen Town Hall on 10 October 1959. In a rousing speech, the well-known space pioneer had convinced Lampoldshausen’s residents that a test stand site for rocket engines would be very important for the community. A leading space and rocket technology expert, he had returned from France to Germany in 1954 to resume his work into space research.

Prof. Eugen Sänger (1905-1964)
Prof. Eugen Sänger (1905-1964) - founder of the DLR site in Lampoldshausen

Hopmann, Lemwerderer 1999

He had overcome an important hurdle and could now begin construction of a test site for the ‘Research Institute for Jet Propulsion Physics’ – which he had founded in Stuttgart – with the aim of testing liquid-fuelled rocket propulsion systems. Indeed, he had chosen the perfect moment, as the ban on rocket research ended with the revocation of the Occupation Statute in 1955, enabling space research to be conducted once again in West Germany after 10 years. Federal states, universities and industry all wanted to be involved during this ‘founding phase’. The first construction phase of the test site was completed in 1963 – the same year in which the location was selected for the first major European space project. This endeavour would focus on the development of a European launcher. ‘Astris’, the German-developed engine for the third rocket stage, thus came to be tested in Lampoldshausen. The site was expanded for that purpose, with test stands P3 and P4, developed and constructed for tests under both high-altitude and ground-level conditions. At the same time, the scientists and engineers based at the site in Lampoldshausen were conducting research into high-energy liquid-fuelled engines.

Lampoldshausen assists with the birth of European spaceflight

In 1975, work began on the Ariane launcher under the leadership of the newly-founded European Space Agency (ESA). This would allow Europe to gain independent access to space. In order to prepare the launcher for its journey into space, its engines were first tested at the site in Lampoldshausen. Important tests of the Viking engine were conducted here. The success story really began with Ariane’s first triumphant launch on 24 December 1979. Today, 40 years on, the researchers are working on Ariane 6, which is earmarked to be launched for the first time in 2020. The DLR site in Lampoldshausen is responsible for testing the Vulcain-2.1 main-stage engine, the Vinci upper-stage engine, and the entire upper stage of the Ariane 6. In the glass-walled visitor centre, a 1:10-scale model that is roughly six metres in height attests to the close relationship between this site and the new workhorse of European spaceflight. This is the youngest member of the Ariane launcher family and succeeds Ariane 5, which will retire in 2023, after 27 years of service. The lower stage of Ariane 6 is adorned with the flags of the 13 ESA member states involved in the project. These show that such an endeavour cannot be achieved without teamwork, and also demonstrate the site’s important position within the space community. The many facets of future space propulsion - including methane.

Before a launcher is qualified for launch, its engines undergo several thousand seconds of test firings on purpose-built test stands. In Lampoldshausen, they receive the finishing touches. One of the core tasks of this site over the coming years will be to develop the test stands in a technologically flexible way and to optimise their cost-effectiveness.

In addition, DLR engineers are constantly working on developing new technologies for future engine concepts. One example is the propellant combination of methane and liquid oxygen (LOX), which is playing a promising role in the development of new, liquid-fuelled space propulsion systems. In the Prometheus project, DLR researchers are working to ensure that LOX/methane technology will soon be ready for use in European spaceflight systems. It will be tested on the site’s P5 test stand, demonstrating that these large structures remain ground-breaking, despite having been constructed during the facility’s early years. P5 was originally built for the development of the Vulcain main-stage engine of Ariane 5 and went into operation in 1990. Development tests on the Vulcain-2.1 engine for the new Ariane 6 are currently taking place on this stand. Behind the scenes, however, a team of DLR scientists is already preparing the test stand for its new task and developing the necessary infrastructure for the Prometheus project. "A LOX/ methane technology demonstrator with 100 tonnes of thrust will be put through its paces on the P5 test stand from 2020," says Anja Frank, Head of Test Facilities. "A smooth and swift transition to LOX/methane from the traditional propellant combinations used in current engines – liquid hydrogen and liquid oxygen – is essential to ensure that Europe remains competitive in the launcher sector after Ariane 6." A future LOX/methane engine can reduce the costs of the European main-stage Vulcain engine – which was developed in the 1980s – by a factor of 10 and be reusable.

The future of propellants is emerging at DLR Lampoldshausen

Future propellants are also an important part of the research being carried out in the Harthausen Forest. Until now, satellite propulsion systems have used hydrazine. This propellant can be stored for long

periods of time and works reliably even under space conditions, making it indispensable for space missions today. However, it is also harmful to human health, and handling hydrazine on the ground – during transport, fuelling and launch preparations – is complex and expensive. This is why DLR researchers are now analysing, evaluating and testing new fuels, referred to as ‘green propellants’. These are environmentally friendly, cost-effective and easy to handle, and in the future they will be at least as efficient as conventional propellants.

Getting closer to next-generation engines through machine learning

Artificial intelligence (AI) is playing an increasingly important role in the space propulsion sector, in order to accelerate the development of new generations of engines. Machine-learning algorithms can independently develop predictive capabilities using previously generated data, and these can then be used for data-based calculations, decisions and optimisations. However, these kinds of developments at the site remain invisible to the group of visitors. They are happening on computers in the offices, including those of Jan Deeken and Günther Waxenegger-Wilfing from the System Analysis group at the Institute of Space Propulsion. They are using neural networks as part of the Liquid Upper stage deMonstrator ENgine (LUMEN) project, in which the experts at Lampoldshausen are investigating the interactions between all the components of a rocket engine – from the combustion chamber to the turbopumps and valves. A complete model engine for research in a test stand environment is due to be created for the first time by the end of the project in 2020. "One big advantage is that we no longer have to wait for days to get the results of calculations. The new ‘tool’ enables us to combine the speed of simple modelling with the accuracy of numerical methods, and provides us with results in seconds. This has given us new insights into the interactions between components in a rocket engine," says Deeken. AI has already proven beneficial in the design of combustion chamber cooling channels. A neural network trained for this purpose is able to predict the complex behaviour of methane – which is used as a coolant, as well as a propellant – and is thus a central component of automated cooling-channel design for the LUMEN combustion chamber.

No downtime

The visitors have now come to the end of their tour. They are one of the many groups that visit DLR each week to get a picture of past and present developments in space propulsion. The future of spaceflight is

being driven forward in many offices, laboratories and on test stands across Europe, with DLR Lampoldshausen at the very forefront. "The exciting and unique thing about this DLR site is that scientists can conduct research, develop technologies and carry out tests at different scales," says Stefan Schlechtriem. As Director of the Institute of Space

Propulsion, he has been in charge of the site for 10 years. Under DLR’s Strategy 2030, he is pursuing a clear vision of the future with a focus on innovative test stand technologies and technical expertise. Schlechtriem attaches great importance to stable foundations, both technologically and through strategic partnerships. "For space propulsion
systems, there is no other location in Europe where research, development, design, planning and tests on large test stands are so closely interlinked as they are here in Lampoldshausen. This is almost unparalleled in Europe and offers immense potential. We have excellent prospects for exploiting it."

This article was published in DLRmagazine 162


Anja Kaboth

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

Julia Heil

Editorial management DLRmagazine
German Aerospace Center (DLR)
Communications and Media Relations
Linder Höhe, 51147 Cologne