On 14 February 2021, the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) will receive the first upper stage of the European Ariane 6 launcher. The fully functional test module will be subjected to extensive testing at DLR's Lampoldshausen site over the coming months. The aim is to verify that the rocket's upper stage is fit for flight – a major milestone on the way to its first launch, which is planned for the second quarter of 2022.
After being manufactured at the ArianeGroup factory in Bremen, on 29 January 2021 the upper stage was dispatched in a specially designed container. With the upper stage inside, the container weighed approximately 57 tonnes. It is roughly 14 metres long, seven metres wide and six metres high. Its journey has been split into several stages – being carried by ship then by heavy transporter – via the Weser, Hunte, Ems and Ijsel rivers, then the Rhine and Neckar rivers, before reaching its final destination of Lampoldshausen, near Heilbronn.
Unique, flexible and efficient – DLR's infrastructure and expertise for future space transport systems
"By launching its test campaign for the upper stage of the future European launcher, Ariane 6, DLR is demonstrating its scientific and technological expertise in space research," says Professor Anke Kaysser-Pyzalla, Chair of the DLR Executive Board. "Our new P5.2 test rig meets the requirements of modern space transport; it is cost effective and can be quickly adapted. We are harnessing the potential of flexible testing facilities and working alongside industry to lay the groundwork for the future of European space transport."
"Thanks to its test facilities, DLR is able to validate not only engines and individual launcher components, but also entire cryogenic upper stages," says Hansjörg Dittus, Member of the DLR Executive Board for Space Research and Technology.
Refuelling and hot-firing tests during test campaign lasting several months
Following the arrival of the upper stage, it will be integrated into the new P5.2 test rig. The launcher will be lifted by a crane, hung on the test rig and fastened in place. The upper stage measures 5.4 metres across and is more than 10 metres high. It weighs approximately seven tonnes without fuel, but 38 tonnes once fuel has been added.
P5.2 was specially designed and constructed by DLR for the purpose of testing the upper stage of Ariane 6. The upper stage consists of the Vinci engine, which can be ignited multiple times, the tanks for the liquid hydrogen and liquid oxygen, piping, valves and the electronic and hydraulic control and steering systems.
Cryogenic upper stage – low temperatures, major challenges
Lasting several months, the test campaign will involve a clean fuelling and defuelling test and four 'hot-firing' tests. In the fuelling and defuelling test, the focus will be on filling and emptying the tank safely. The test is designed to build experience and facilitate the development of safe methods for carrying out such processes but also for aborting them if necessary. The fact that this is a cryogenic upper stage makes this no simple task. The hydrogen and oxygen that serve as the fuel must be cooled to extremely low temperatures –minus 183 and minus 253 degrees Celsius respectively. These temperatures require the use of specialist materials that must be handled very carefully. Ariane 6’s Vinci engine is ignited up to three times during the hot-firing tests – which simulate different flight scenarios – with the thrust and duration of the ignition varying from test to test. With this flexibility, Ariane 6 will be able to deploy its payloads in different orbits.
"With the P5.2 test rig and the test programme for the Ariane 6 upper stage, DLR has all the test facilities it needs in Lampoldshausen to comprehensively test all the space engines that Europe will require in the future," says Stefan Schlechtriem, Director of the DLR Institute of Space Propulsion, describing the unique test rig. "In addition, new development programmes and standardised acceptance tests of Ariane flight engines can take place in parallel. This makes it the most flexible and efficient test centre for rocket engines in Europe."