Tests are continuing, particularly in Guyanese Space Center, but many teams are refining the equipment of tomorrow. On the menu ? The Phoebus upper stage and its performance gains, the future reusable Prometheus engine which is reaching new stages, and Arianegroup, which is preparing Susie.
The European launcher sector is going through a crisis, and the waves will only calm down when rockets can once again fly regularly, with the efficiency that the continent had for four decades. But beyond the soap opera around the Ariane saga and her sultry cousin Vega, development work continues behind the scenes. For Ariane 6, this will translate into several waves of developments, which will improve its performance without necessarily increasing costs.
Something concrete with Phoebus
There is the expected introduction of new, larger auxiliary solid boosters (the P160s)… but also the Phoebus upper stage, currently in development via a joint team of ESA, ArianeGroup and MT Aerospace. This rocket stage, which will replace the current second stage of Ariane 6 from 2026-2028, has tanks and a specific carbon fiber structure, which will make it lighter and promise much better performance ( we are talking about a gain greater than a ton of payload)!
The fact remains that Phoebus is an experimental project, so a long sequence of tests is required. Good news, these can begin, because a first prototype tank of two meters in diameter is ready for an extensive test campaign. The teams are particularly attentive to their resistance in cryogenic conditions, so that they can accommodate liquid hydrogen (most “classic” carbon fiber alloys have problems with extreme cold). This is an innovative field, only one other launcher of the scale of Ariane 6 considering carbon tanks is also under development. This is the Rocket Lab Neutron.
Reusable with Prometheus
Another area that Europeans are eager to explore is that of the reuse of the main floors. For this, as we know, the ESA is committed to several programs, the central element of which is the Prometheus liquid methane-oxygen engine. The latter was turned on for the first time a few months ago (June 22), but it was in October that it passed its most promising test yet, an ignition followed by 30 seconds of pushing, before a planned extinguishing and re-ignition! Progress that seems discreet, but everything needs to be done in Europe on the subject. The Arianegroup teams claim to be preparing the Themis demonstrator in parallel for its first “jumps” with a Prometheus engine planned for next year in Kiruna, Sweden. Despite everything, no date has been announced for this already very late program. It’s about preparing for the future in the medium or long term…
Any progress with Susie?
Arianegroup also chose to show its progress with the Susie program (
Smart Upper Stage for Innovative Exploration), unveiled last year and which remains a concept to this day, not yet funded by European authorities. Susie, which is at the same time a second stage of a reusable launcher, an option for a manned or cargo capsule and an autonomous shuttle, will be (if the project comes to fruition) capable of landing alone vertically and without a parachute. It is this aspect in particular that the teams chose to test by developing a model responsible for validating the models, and in particular the atmospheric flight control surfaces.
It is also a way of preparing the ground, a few days before the ESA ministerial meetings, by showing that the Susie project is based on concrete facts and not on a few Powerpoint slides. Will this be enough to convince States in a tense context? Nothing is less sure. But the various authorities, ESA in the lead, are right to continue development, we already know that Ariane 6 will be able to evolve and improve its major elements more simply than with the previous generation. If only she could fly…
Source : ESA
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