Airbus ships first lighter Ariane 6 engine mount, 400 kg saved

A structure that holds a rocket engine in place has just left the Netherlands for France. Airbus Netherlands has shipped the first lightweight Vulcain Aft Bay for Ariane 6, designated Flight Model 16 (FM16), to ArianeGroup in France via Rotterdam. The company's president, Rob Postma, announced the shipment in a LinkedIn post on 21 October, and the part is expected to fly for the first time aboard an Ariane 6 mission in 2027.

The Vulcain Aft Bay is a structural assembly fixed to the base of Ariane 6's main stage. It supports the Vulcain 2.1 engine and transfers the thrust it generates into the rest of the rocket. The current part weighs about five tonnes. The redesigned version is 55 millimetres shorter and 400 kilograms lighter than its predecessor, according to Postma.

The figure has moved more than once. In July 2024, the Netherlands Space Office reported an 800 kg saving, citing Airbus Netherlands' director of strategy, sales and business development, Frank Meiboom. In 2025, Leonardo Times, an aerospace magazine run by students at Delft University of Technology, reported a reduction of more than 550 kg after a visit to the Airbus Netherlands production facility. Postma's announcement does not address the gap between these numbers and the 400 kg he now gives, which is half of the original target.

The aft bay is one of the final upgrades of the Ariane 6 Block 2 package, which also includes the more powerful P160C solid rocket boosters. Those boosters first flew on an Ariane 64 in June 2026. The European Space Agency (ESA) identified the lighter aft bay as one of the remaining steps meant to improve the rocket's performance and competitiveness. The agency has since confirmed it will not pursue the Block 3 package, saying there was "no programme need or justification" for it.

For Airbus Netherlands and ArianeGroup, the shipment closes a development step: the first flight-standard unit is now on its way to the integration site in France. For Ariane 6, the lighter aft bay is among the last identified improvements, and the first mission to carry it is expected in 2027. Until that flight, the saving remains the company's own figure, and the earlier estimates show how far the expected gain has already shrunk.