ESA back in heavy launch business after Ariane 6 success • The Register

The European Space Agency’s new launcher, the Ariane 6, completed its maiden flight on Tuesday.

The Agency (ESA) celebrated the launch with a post that offered little detail other than “At 17:06, a little over an hour after liftoff, the first set of satellites on board Ariane 6 were released from the upper stage and placed into an orbit 600km above Earth. Satellites and experiments from various space agencies, companies, research institutes, universities and young professionals were included on this inaugural flight.”

But not all was well. The mission plan also called for Ariane 6’s upper stage to perform a demonstration in which its Vinci engine was restarted – to test the craft’s ability to move into different orbits so it can conduct missions that require cargos to be dropped in several spots under conditions of microgravity.

Ariane 6 can theoretically do that, thanks to its inclusion of what the ESA describes as a “novel auxiliary propulsion unit” (APU).

The ESA hoped to demonstrate the APU by releasing a pair of “re-entry capsules” that would burn up in Earth’s atmosphere.

Sadly, something went less than perfectly.

In a post-flight Q&Asession, Martin Sion, CEO of ArianeGroup – the private biz responsible for building and operating Ariane 6 – said the APU fired once, allowing the upper stage to release a second set of satellites, but then failed after a second ignition.

“We don’t know why it stopped,” he admitted, going on to explain that ArianeGroup doesn’t yet have the data it needs to analyze the situation.

Whatever happened, Sion revealed that the Vinci engine did not start, so the demo mission was not possible. The upper stage was placed in an orbit that ESA officials assured does not represent more of a hazard than comparable pieces of hardware, and the capsules stayed aboard.

“But all the rest of the mission was according to plan,” Sion noted, pointing out that the demos were just that – efforts to understand how the rocket behaves in microgravity, because that’s not possible on Earth.

Despite the problems with the demo phase, ESA officials declared the launch a triumph – because it matched the performance of the agency’s old Ariane 5 launcher. Officials also pointed out that it’s not every decade a new heavy launcher takes to the skies – and that this one went so well a second Ariane 6 launch is a near-certainty this year. Six are planned for 2025.

Ariane 6 ascends for the first time – Click to enlarge

Officials pointed out that future launches can take place without the APU being fixed, because not every mission will involve a phase in microgravity.

That’s welcome news, given the ESA funded the rocket in 2016 under a plan that called for it to fly in 2020 – a year in which the agency still operated Ariane 5.

That launcher last flew in July 2023, and Europe has been without a heavy launcher ever since.

Now it has one that can carry over 20 tons into low Earth orbit when Ariane 6 is equipped with four external boosters, or 10.3 tons in a smaller configuration with two boosters. ®