SVE NEWS & ESA.INT Sharing Series — Ariane 6 takes next step to first flight with upper stage hot fire tests

These tests, which began on 5 October 2022, represent a significant step forward thanks to the specially-built P5.2 test bench at Germany’s DLR centre for engine and stage testing in Lampoldshausen. The P5.2 test bench subjects the entire upper stage to operating conditions representative of a flight from Europe’s Spaceport in French Guiana, with the exception of vacuum and microgravity.

Vinci, the upper stage engine of Ariane 6 fed by liquid hydrogen and oxygen, can be stopped and restarted multiple times – a critical capability for the complex missions demanded by launch customers today: placing several satellites into different orbits and de-orbiting the upper stage, to leave an absolute minimum of hazardous debris in space.

In addition to restart capabilities and endurance in space, Vinci has been developed for reliability, simplicity and lower costs

This test series is a critical milestone on a development path that will soon see Ariane 6 replace Ariane 5 as ESA’s heavy launcher. For more than a quarter century, Ariane 5 has been a reliable partner for commercial, institutional and scientific clients – one of its most notable missions was the 25 December 2021 flight that carried the NASA/ESA/CSA James Webb Space Telescope to its operational outpost in deep space. But Ariane 6 will be an even more versatile vehicle, further strengthening Europe’s autonomy in accessing space.

COMPLEX TESTING

The tests being run at Lampoldshausen are also evaluating an innovative Auxiliary Power Unit (APU) which works in tandem with the Vinci engine and is instrumental to Ariane 6 upper stage performance. In order to restart in space, earlier engines relied on large quantities of tanked helium to generate the necessary pressure and temperature in the propellant tanks and to ensure there are no bubbles in the fuel lines. But the APU delivers these conditions using only small amounts of the cryogenic hydrogen and oxygen already carried in the main tanks.

This test series is being run by DLR and ArianeGroup, the Ariane 6 launcher prime contractor. When the test series is complete, this upper stage – integrated by ArianeGroup at its facility in Bremen, Germany – will be shipped to ESA’s ESTEC technical centre in the Netherlands for stage separation and acoustic tests.

Ultimately, the Lampoldshausen tests will investigate hardware behaviour and system function of the complete stage with its tanks, engines and avionics. “The preparation for these hot firing tests is even more complex than for an actual launch,” says Ariane 6 launcher programme manager Guy Pilchen, noting that: “Our colleagues in Lampoldshausen have decades of experience in rocket propulsion with extremely advanced test facilities. With ArianeGroup colleagues to control the upper stage and DLR people operating the test bench, we couldn’t ask for a better team.”

ESA Director of Space Transportation Daniel Neuenschwander adds that this new engine and the upper stage it powers are indispensable components of Ariane 6 and its objective – to guarantee that Europe maintains independent, competitive and sustainable access to space:

“It’s a fact in the 21st century that Europeans depend on space for safety, prosperity and security. Europe needs to work toward complete autonomy in accessing and operating in space. Ariane 6 is key to this and we are eager to see the liftoff from Europe’s Spaceport in French Guiana.”