Last month, an Ariane 5 rocket carried the James Webb Space Telescope (JWST) safely to space, the latest of 112 total launches for the European Space Agency’s (ESA) primary workhorse rocket. With a 95.5% success rate, the Ariane 5 has been a reliable ride to space for decades, but its story is about to come to an end. ESA is no longer building new Ariane 5 vehicles, instead developing its next-generation rocket, the Ariane 6, which is intended to provide cheaper access to space. This week, the first completed core stage of a new Ariane 6 rocket arrived at the spaceport outside Korou in French Guiana for testing.
ESA’s plan to replace the Ariane 5 has been in the works for some time, but the process sped up dramatically in 2014 when a planned upgrade to the Ariane 5 was canceled, enabling funds to be directed towards the development of the Ariane 6 instead. As of January 23, 2022, there are only five Ariane 5 launches remaining, four of which are scheduled for 2022. These are dual-satellite launches, carrying (mostly) telecommunications payloads to geosynchronous transfer orbits.
The final launch of the Ariane 5 will come in 2023, carrying ESA’s Jupiter Icy Moons Explorer (JUICE). JUICE will study three ocean worlds around Jupiter: Ganymede, Callisto, and Europa, in concert with NASA’s Europa Clipper mission. At a press briefing on January 6th, Arianespace’s Chief Executive Stéphane Israël said “we are quite happy that we will end the brilliant life of Ariane 5 with such an ambitious mission for ESA.”
The successful launch of JWST last month certainly provided renewed faith in the Ariane 5’s ability to pull off important missions like JUICE. A partial failure during a 2018 launch had some commentators worried about its reliability. But the Ariane 5’s pinpoint accuracy in December gave JWST at least an additional 5 years of life, saving fuel initially earmarked for finetuning the telescope’s trajectory.
The Ariane 6 will have big shoes to fill. It was initially designed to carry smaller payloads to orbit than the Ariane 5, but it has evolved to have a similar mass-to-orbit capability. It has two configurations, one with two solid rocket boosters, which can put 4,500kg into a geostationary transfer orbit or 10,300kg into low Earth orbit, and one with four side boosters, which can launch 11,500kg into a geostationary transfer orbit and 20,600kg into low Earth orbit.
The rocket’s liquid-fueled core stage and upper stage will both undergo testing in French Guiana in the coming months, being integrated for a hot-hire test later this year (where the engines are fired without lifting off the pad). Additional tests will ensure that fueling processes and flight software are also working as expected. Meanwhile, back in Europe, testing continues to see how the upper stage will perform in outer space conditions.
If all goes well, the first launch of Ariane 6 will come in the second half of 2022, with three further launches to follow in 2023.
Featured Image: Ariane 6 arrives in French Guiana on Janary 17th, 2022. Credit; ESA/CNES/Arianespace.