The German Aerospace Center (DLR) has successfully tested the Ariane 6 upper stage for the first time on October 5, 2022. A hot run test is a highly demanding test: the aim is to simulate flight-like conditions on the test bench. The aim is to demonstrate the interaction of all components for launch preparation and flight, and to simulate the loads that a rocket stage has to withstand on its way into space. The upper stage is the part of a multistage rocket that travels the longest. It transports the payload and deploys it at the desired location at the correct speed. This test marks an important milestone on the way to the maiden flight of the new European launch vehicle Ariane 6. The upper stage is a rocket stage designed from scratch.ArianeGroup.
Demanding tests for use in space
The stage consists of two main tanks filled with liquid hydrogen and liquid oxygen, the new Vinci engine, which can be reignited up to four times, and the APU (Auxiliary Power Unit), an innovative propulsion unit. It makes Ariane 6 even more versatile. The focus of this first hot-run test was filling the stage with cryogenic propellants and testing the re-ignitable Vinci engine. The team ofDLR Institute for Space Propulsionalso checked all the systems associated with the upper stage, such as the flight software. “This first successful test run has shown us that the skills acquired in testing space propulsion systems in Lampoldshausen over the decades are a crucial guarantee for the success of the European Ariane family,” explains Prof. Dr.-Ing. Anke Kaysser-Pyzalla, Chair of the DLR Executive Board. “I would like to thank the team that made this first test of the complete Ariane 6 upper stage a success.”
“With Ariane 6, Europe will have a launcher that will be the cornerstone of European space activities for many years to come. It is the ideal rocket to launch our institutional missions and thus guarantee access for all European space users – a capability that has become indispensable in today’s geopolitical environment,” emphasizes Dr.-Ing. Walther Pelzer, DLR board member and head of the German Space Agency at DLR. “I am therefore particularly pleased that we have reached this essential milestone in the development of Ariane 6. It is a great success of the cooperation between DLR, ESA and the German and European space industry.”
“In the 21st century, Europeans undoubtedly depend on data from space for their security and prosperity. Europe must work towards full autonomy in accessing and using space. Ariane 6 is key and we look forward to seeing it launch from Europe’s spaceport in Kourou, French Guiana,” says Daniel Neuenschwander, ESA Director of Launch Systems.
“The successful hot-run test is an important step on the way to the qualification of Ariane 6 and a successful maiden flight. Developed, produced, assembled and tested in Germany, the Ariane 6 upper stage demonstrates the know-how of the ArianeGroup, its industrial partners and DLR,” explains Pierre Godart, CEO of ArianeGroup GmbH to the so-called combined tests of the launch vehicle and the launch site in Kourou. With the combined forces in Lampoldshausen, Kourou and other locations and thanks to the excellent teams of everyone involved, we will achieve technical excellence. In this way, the Ariane 6 will become the success story of the European Launcher updated.
Overheating tests: supreme discipline on the test bench
A total of up to three hot-running tests are planned for the upper stage at DLR Lampoldshausen. As a rule, after several weeks of intensive preparation, they each take around 17 hours. All aspects are simulated, including the preparation and post-processing of the stage. This includes filling up with liquid oxygen and liquid hydrogen and emptying the tanks after the end of the test. The test bench team collects a large amount of important data during the tests: for example on the ballistic phases in which the upper stage flies without thrust, the so-called coast phase, on the pressure build-up in the tanks before the engine ignition, on the engine re-ignition and about the function of the nozzles, which are used for position control.
“Overheating tests are the supreme discipline on the test bench. They place the highest demands on the technology and are therefore a particular challenge for the team and infrastructure,” says Prof. Stefan Schlechtriem, Director of the DLR Institute of Space Propulsion. “In addition, for the first time in the long history of the Ariane program in Europe, we are testing a cryogenic upper stage on a newly developed test bench – a double premiere,” adds Schlechtriem. The findings from these tests are fundamental to finalizing Ariane 6 and getting it ready for space. The team led by Anja Frank, head of the test facilities at the Institute for Space Propulsion, prepared the tests accordingly. In the last few months, maximum concentration was required to complete all the preparations for the upper stage, which weighs seven tons and has a diameter of 5.4 meters and a height of 11.6 meters. It was just as important to develop and write complex software programs in order to be able to precisely control and monitor all processes during the tests.
The first warm-up test of the upper stage of the rocket – which is also known as the “Hot Firing Model” (HFM) – heralds an important phase in the entire Ariane 6 launcher development, and not just in terms of technology: “This is also a very emotional and exciting moment for everyone involved , when the newly developed upper stage is ignited on the test bench for the first time,” emphasizes Schlechtriem.
In the center of attention: re-ignitable Vinci engine with cryogenic propellants
The Ariane 6 upper stage is equipped with a re-ignition engine called Vinci. It can be re-ignited up to four times and can burn from a few seconds to more than 14 minutes. This makes Ariane 6 very flexible, it can cover a wide range of missions and head for several target orbits, each with a different mission duration. It is particularly suitable for transporting satellite constellations in which the individual satellites are placed in different orbits. With the propellant combination of cryogenic, i.e. cryogenic liquid oxygen and hydrogen, the Vinci engine provides the necessary thrust to place the payloads exactly at the desired position and at the correct speed in the respective orbit.