Ariane 6 pre-show: wet dress rehearsal completed

Similar to the rehearsals conducted with a test rocket during combined test campaigns, this time the real flight model, payload, launch pad and ground teams underwent every step of the launch operations; from pumping 180 tons of propellant – liquid oxygen and liquid hydrogen – into the waiting Ariane 6, rolling back the mobile gantry, running all the ground control software and more.

“The wet dress rehearsal is the very last milestone before launch,” says ESA’s Guy Pilchen, project manager of the Ariane 6 launch vehicle. first time.”

Top tip: fill slowly with supercooled fuel

One of the first steps was rolling back the colossal, 90-meter-high Ariane 6 mobile gantry building 120 meters away from the launch pad – the first time the entire rocket was free.

Pumping fuel into the Ariane 6 then took about 3.5 hours, while technicians in the control center first began slowly cooling the pipes, valves, tanks and engines from French Guiana’s tropical temperatures of about 30 degrees Celsius to to the super temperature. cooled temperatures of the soon-to-arrive cryogenic fuels.

The propellants used by Europe’s new Ariane 6 rocket are as much art as engineering, being supercooled to –180°C for the oxygen and –230°C for the hydrogen fuel. At these temperatures, moisture already present in the pipes would immediately freeze, which could lead to blocked valves. To prevent this, any hint of air or moisture from the atmosphere was flushed from the system by the inert (non-reactive) gas, nitrogen, before refueling began.

Once the tanks were full, the teams continued to refill them as the liquid fuels would gradually boil away in the sun. The fuel was then removed from the rocket in preparation for launch.

Countdown to just a few seconds

“The rocket, the launch pad and the teams from ESA, CNES and ArianeGroup all delivered great performances, and everything went smoothly – I couldn’t be more proud,” says Pier Domenico Resta from ESA, “after all these years of preparation we have very close to launch.”

Data from the rehearsal is now being analyzed and results are expected on June 26, which will confirm the launch date when Ariane 6 will go through the same process, except finally igniting and completing the last few seconds – taking off from Earth for the first time.

We’ve come a long way

The first parts of Ariane 6 arrived in French Guiana from continental Europe in February 2024 via the ‘spaceship’ Canopée. The main stage and upper stage were assembled in March, followed by the handover of the two high-performance P120C boosters in April.

May also saw the arrival of the first Ariane 6 passengers in Kourou – a diverse selection of experiments, satellites, payload deployers and reentry demonstrations representing thousands of people from across Europe, from students to industry and experienced space actors NASA and ArianeGroup.

The payload was integrated onto the ‘ballast’ at the end of May and just a few days ago the ballast was mounted on the top of the rocket and the fairing closed around it – the last time the Ariane 6 payload would see light.

From Earth observation to technology demonstrations testing wildlife tracking, open-space 3D printing, open-source software and hardware, and scientific missions in search of the most energetic explosions in the universe: the passengers on Ariane 6’s first flight are a testament to the rocket’s adaptability. complexity and its role for the future – launching any mission, anywhere.

“Ariane 6 was designed and developed to secure Europe’s independent access to space,” explains Toni Tolker-Nielsen, ESA’s Space Transport Director.

“With the first launch of this new heavy rocket, Europe is back in space. Space activities are becoming an integral part of any modern economy, Ariane 6 will ensure that Europe misses nothing and will serve its exploration and scientific missions.”