Ariane 6 Passes Last Full-Duration Rehearsal Before Inaugural Flight

Europe’s mightiest and heaviest rocket—the Ariane 6—has completed the last full-duration rehearsal in preparation for its inaugural flight.

The test rocket went through a complete launch countdown procedure on its new launchpad at Europe’s Spaceport in French Guiana, followed by full firing of the core stage’s Vulcain 2.1 engine.

The fully automatic countdown sequence was paused less than three minutes before the ignition due to “a little anomaly in the transient threshold pressure,” the European Space Agency (ESA) notes. The Ariane 6 was placed in a safe configuration and the countdown resumed in 45 min.

Vulcain 2.1 engine of the core stage ignited and burned 125 tons of liquid oxygen and 25 tons of liquid nitrogen. However, the 860-ton rocket continued to stay firmly on the ground amid the clouds of smoke and steam from the water deluge system, as the four side boosters were not ignited.

During the engine burn, the rocket also passed a gimbal test as the engine’s nozzle was moving, which would be used to keep an ascending rocket on course.

ESA initially announced that the hot-fire test will last eight minutes, which represents the real time that it will take Ariane 6 to leave the Earth and reach space. After that, the core engine will shut down and the core stage will separate from the upper stage which continues the mission on its own propulsion.

However, the post-test statement said that the core engine only made a seven-minute full firing. The live stream showed that the engine’s operation visibly changed in the eighth minute of the burn.

Nevertheless, ESA Director General Josef Aschbacher praised the program participants—the rocket’s lead contractor and designer ArianeGroup, launch operator CNES, and the agency itself. “We are back on track towards resecuring Europe’s autonomous access to space,” he said.

“The success of this long-duration hot-fire test of the Vulcain engine enabling us to validate operation of the core stage is very good news, taking us closer to Ariane 6’s inaugural flight,” said Philippe Baptiste, chairman and CEO of French space agency CNES.
The new rocket already passed a shorter burn in September when Ariane 6’s tanks were filled and its Vulcain 2.1 engine briefly ignited and switched off. Another filling and draining test took place in October to check the launch system functions such as draining fuel in the presence of multiple simulated failures.

According to ESA, it will take about two weeks to analyze the latest rehearsal data collected from 800 sensors.

A last hot-fire test of the upper stage is planned for December at the Lampoldshausen test center from Germany’s DLR aerospace agency. ArianeGroup CEO Martin Sion mentioned that the designers still have to carry out a few additional tests to demonstrate fault tolerance, deliver the first launcher to Kourou, and perform the launch system qualification review.

Successful trials will enable ESA to choose a launch date in 2024. The inaugural launch will be still a part of the development phase. After that, CNES will hand over Ariane 6’s operation to Arianespace, which will be responsible for its commercial use. The latter has an orderbook for 28 launches with the new rocket.
It can be launched in two configurations. Ariane 64, with four boosters, will have a capacity to place up to 12 tons in geosynchronous transfer orbit (GTO) in dual-satellite launch configuration, and up to 20 tons in low-Earth orbit.

The 530-ton Ariane 62 will have two boosters and a payload capacity of 4.5 tons to GTO and 7 tons to Sun-synchronous orbit.