After several months of delay, the maiden flight of Ariane 6 is scheduled for the last quarter of 2023.
With an Ariane 6 order book as full as an egg, we must already plan for the next launches.
This is why the dedicated teams at ArianeGroup's Girondin sites in Saint-Médard-en-Jalles and Le Haillan have been entirely focused on the production of Ariane 6 rockets for more than a year now.
The emotion is palpable when Frédéric Dauch pushes the door of the large hangar, in one of the ArianeGroup factories in Gironde, in Saint-Médard-en-Jalles near Bordeaux.
Behind sits proudly, in the middle of the room, a skirt, a huge metal piece in the shape of a cylinder.
Fully wired and connected, it is ready before leaving for Kourou in French Guiana, for the maiden flight of Ariane 6 scheduled for the end of the year.
Responsible for the "solid propulsion" program for Ariane 6, Frédéric Dauch explains that the dedicated teams at the ArianeGroup sites in Saint-Médard-en-Jalles and Le Haillan have been entirely focused on the production of Ariane 6 rockets for more than One year already.
The factories which bring together 3,400 employees, or around 40% of ArianeGroup's workforce, work in particular on the boosters for the new launcher of the European Space Agency (ESA).
Gases escaping at more than 3,000°C on takeoff
Also called Equipped Solid Rocket (ESR), these propellant-powered solid combustion engines, located on the sides of the rocket, are ignited on takeoff and allow the rocket to tear itself away from gravity and exit the atmosphere. earthly.
The gases emitted by the propellant then escape from the nozzle, which can be vulgarly described as engine exhaust pipes, at more than 3,000°C for two minutes.
Almost three times the temperature of molten lava.
To withstand such temperatures, special composite materials are needed, designed a few kilometers from Saint-Médard, on the Haillan site.
These composite materials are deposited in the nozzle by a "winding" process.
"We also manufacture in Haillan about ten parts that go into the composition of the nozzles", continues Frédéric Dauch.
The nozzle, an object about three meters high and weighing between two and three tons, is then assembled on site, before being also shipped to Guyana.
Robotization and automation
The group and its subsidiary Arianespace are aiming for around ten Ariane 6 launches per year, compared to five to six for Ariane 5, the last two launches of which will take place this year.
And since the new Ariane rocket has two versions, the A62 equipped with two boosters, and the A64 with four boosters, compared to a single version with two boosters for Ariane 5, this implies an acceleration of the rates on the production lines and assembly of ArianeGroup, and greater modularity.
“For example, we will have to release 36 nozzles per year, compared to 12 for Ariane 5.” And with an Ariane 6 order book as full as an egg, we must already plan for the next launches.
"In our Haillan plant, we are already working on Ariane 6 flights 5 and 6, and even beyond for certain parts...", continues Frédéric Dauch.
To meet these challenges, the key words for mass production of Ariane 6 are robotization and automation.
In Haillan, ArianeGroup has notably equipped itself with an impressive robot capable of lifting the nozzle, and placing elements in it to the nearest micron.
But several “high value-added” tasks can only be done by hand.
This is the case with the gluing of the parts of the nozzle, “because this requires know-how, a feeling, which is difficult for a robot to transcribe.
“Ariane 6 was designed to respond to market developments”
The main principles and reliability of Ariane 5 are repeated for Ariane 6, namely boosters for takeoff, and two stages powered by liquid propulsion engines (hydrogen and oxygen) for the rest of the flight and the positioning in orbit of the "payload", usually satellites, installed at the top of the rocket and protected in a fairing.
"Ariane 6 was designed to respond to changes in the market," recalls Frédéric Dauch.
We have gone from a market with many geostationary satellites positioned at 36,000 km altitude, to a market with more and more constellations of satellites to be launched into low orbit.
And in this field, competition is fierce, which is why we designed this production system to reduce costs by 40% for the new Ariane launcher.
Ariane 6's innovations are nonetheless numerous.
“We have redesigned the entire launcher design to make it simpler with fewer parts, and using new technologies.
The A62 and A64 versions, for example, represent an important development.
“With two boosters on Ariane 6, we carry around four to five tons of payload into geostationary transfer orbit, with four boosters, we are more on twelve tons, explains Frédéric Dauch.
This allows great versatility in terms of missions, which corresponds to the expectations of institutional and commercial clients.
A horizontal rocket assembly
On the engine side, these boosters are equipped with a P120C.
“C as common, because this engine is common with the first stage of the Vega-C rocket, a decision also taken to optimize development costs.
The Vulcain on the first stage (or main stage), already present on Ariane 5, has been retained but optimized.
And Ariane 6 is equipped with a brand new re-ignitable Vinci engine for its second stage (or upper stage).
"This makes it possible to position the satellites even more precisely, without the satellite using its own fuel, or the minimum possible," explains Frédéric Dauch.
This is very important because the more fuel the satellite saves, the longer it will last.
Several elements are assembled in Europe, before leaving by boat for French Guiana, where Ariane 6 has finished being assembled... horizontally, it's a novelty, before being lifted almost to its launch pad.
“Everything is optimized to reduce costs and increase production rates.
“Almost all of the equipment is now qualified, in particular all of the engines, both solid and liquid,” rejoices Frédéric Dauch.
The first meeting between the launcher and the firing point in Kourou took place last summer, and we will continue to carry out these combined tests until the firing tests.
Despite several months of delay, optimism is now in order at ArianeGroup, with a view to the launch of Ariane 6 in 2023.
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