Nighttime Rehearsal for Ariane 6 Leading Up to its Inaugural Flight

Yesterday, a team of CNES, ESA, Arianespace, and ArianeGroup personnel at Europe’s Spaceport in Kourou, French Guiana, completed a full-scale wet rehearsal of the new Ariane 6 rocket. The goal of this rehearsal was to increase the robustness of the launch system and test emergency safety procedures. The test lasted over 30 hours, with three teams working in shifts of 10 hours each.

The wet rehearsal, known as combined test loading (CTLO2.1), is the third time the Ariane 6 ground teams have practiced a full launch countdown. The previous rehearsals took place on July 18 and September 5. This time, the focus was on system robustness and how well Ariane 6 and the teams handle situations at the edge of operational parameters. Unlike the previous tests, which were conducted in daylight, this rehearsal was performed at night to test operations in cooler ambient temperatures.

Ariane 6 uses liquid oxygen and hydrogen as its fuel to power into space. These power-dense liquids need to be chilled to extreme temperatures below -250°C, making them hazardous to work with. The rocket’s tanks hold 180 tonnes of propellant, which is why fuelling and draining operations take so long. Engineers constantly monitor temperatures, pressure in the tanks and pipes, and the ground systems underground pipelines that transport the fuel to the rocket.

The core stage of the Ariane 6 rocket standing on its launchpad is identical to the real thing, but it isn’t meant to leave Earth. The rocket boosters, which use solid propellant, are inert and don’t require fuelling. However, the rest of the rocket, including the Vinci upper stage, which would only fire its engines once separated from the core stage in space, is included in all rehearsals.

Preparation for a launch or rehearsal begins many days in advance. The ground tanks where the liquid hydrogen and oxygen are stored need to be replenished, and the launchpad needs to be primed and prepared. It is an all-hands operation that involves teams from ESA, CNES, Arianegroup, and Arianespace on both sides of the Atlantic.

The recent night-time rehearsal allowed the teams to practice loading the rocket with fuel when the temperature outside is lower. Without the tropical sunlight shining on the Ariane 6 tanks, the fuel inside behaves differently, and the teams need to think and accommodate for condensation and ice formation.

As these operations are delicate, and Ariane 6 is an all-new launch system, the more rehearsals that can be done, the better. Rehearsals help explore the robustness of the systems and provide more confidence in launch countdowns. The data collected from these rehearsals also aids in analysis and smooth operations leading up to liftoff.

The next major test will involve a full eight-minute firing of the Ariane 6 rocket’s main engine, which is scheduled to take place before the end of November. This test will further evaluate the performance of the rocket’s engine. However, for this test, the Ariane 6 test model will remain fixed to the ground.

The teams involved are working tirelessly to get Ariane 6 off the ground and are eagerly anticipating its first launch. With each successful rehearsal, they gain more confidence in the launch system’s capabilities and gather valuable data for future missions. The dedication and efforts of the entire team are commendable as they continue to push boundaries in space exploration.