Key milestones towards inaugural flight:

18 July 2023: Combined tests, hot firing test of the main stage with Vulcain 2.1 engine ignition - At Europe’s Spaceport in Kourou, French Guiana, engineers from ArianeGroup, CNES and ESA, successfully completed for the first time a launcher preparation and countdown sequence.

The 26-hour test included the removal of the mobile gantry, the chill-down of ground and launcher fluidic systems, the filling of the upper and core stage tanks with liquid hydrogen (–253°C) and liquid oxygen (–183°C), and the successful completion of a launch chronology up to the ignition of the Vulcain 2.1 engine thrust chamber by the ground system.

During the exercise fully representative of a launch chronology, the teams successfully tested many degraded and contingency modes, demonstrating that the launcher and the launch base fit correctly. Operational procedures, lower and upper stages, avionics, software, launch base and control bench worked correctly together, and the performance of the full launch system was measured with excellent results.

1 September 2023: Upper stage hot firing test, Lampoldshausen - At German aerospace agency DLR’s rocket engine test centre in Lampoldshausen, Germany, engineers from DLR, ArianeGroup and ESA completed another hot-fire test, representative of the inaugural flight.

Assembled at ArianeGroup’s site in Bremen, Germany, the Ariane 6 upper stage incorporates some of the launcher’s main innovations, enabling it to carry out the widest possible range of launch missions, including complex ones such as large-scale deployment of satellite constellations in low Earth orbit (LEO), or successive injection of payloads into different orbital planes. At the end of its mission, the stage is de-orbited.

The stage includes two main tanks for cryogenic propellants (liquid hydrogen and oxygen) to power the Vinci engine which can be re-ignited up to four times, and the innovative Auxiliary Power Unit (APU).

The upper stage test sequence was representative of its full operating phase during Ariane 6’s inaugural flight.

It involved more than 11 minutes (680 seconds) of operation of the Vinci re-ignitable engine in two boosts in parallel with operation of the APU (Auxiliary Power Unit) which was in operation for a cumulative period of nearly 30 minutes.

The APU makes it possible for Vinci to restart in space, by maintaining adequate pressure in the fuel tanks and preventing bubbles in the fuel lines. The APU uses small amounts of liquid hydrogen and oxygen from the main tanks – replacing a system which relied on large quantities of tanked helium.