On the launch pad in Kourou, French Guiana, this Ariane 6 test model was put through a combined test hot-fire (CTHF) before launch – over seven-minutes ‘hot firing’ of its Vulcain 2.1 main stage. This engine, on a real flight, would work with the boosters to propel the 62-m-tall rocket off Earth and into space. For the test on 23 November 2023 the rocket stayed firmly on the ground, but its upgraded engine burnt through 150 000 kg of supercooled liquid oxygen and hydrogen fuel for the duration of a real flight. Not only was the core stage being tested, but all aspects of the launch pad and operations, too, from the delicate procedure of fuelling both the main engine and the orbital stage stacked above it to testing the thermal effects of a launch on mechanical and electrical components.