Last year we saw the European PROTEIN initiative to develop new heavy launchers. Since the introduction of Ariane 5 in 1996, Western Europe has been part of the select club of space powers that possess the most powerful orbital rockets – capable of placing more than 20 tonnes into low orbit (LEO) – along with the United States, Russia and China. But new heavy launchers in the US – Falcon Heavy, SLS, New Glenn and Starship – and China – CZ-10 and CZ-9 – have relegated Western Europe and Russia to the second division in terms of powerful delivery systems. The Ariane 6 will have comparable power to the Ariane 5, so it is only natural that the European Space Agency (ESA) will study the possibility of developing more capable reusable launchers.
Just a year ago the ESA awarded the companies ArianeGroup – main contractor for the Ariane 5 and 6 – and the relatively modest RFA (Rocket Factory Augsburg) from Germany contracts to study how its European superlauncher could, contracts that would be developed within the PROTEIN program until September 2023. In the study, the excuse to justify the introduction of these heavy vectors was the launch into orbit of solar energy stations that They transmit the generated energy to the Earth using microwave beams, a concept that was in vogue in the 70s and has now been revived with force. (precisely, one of the declared objectives of the future Chinese CZ-9 is to deploy these solar stations in geostationary orbit).
The heavy launchers under the ESA contract for the PROTEIN initiative had to be capable of delivering more than ten thousand tonnes of payload per year to LEO in two scenarios: the launch into polar orbit (SSO) of 4,000 satellites of 11 tonnes each or 50 huge solar stations in geostationary orbit (GEO) of 6,500 tons each. Now, at last, we have been able to see the launcher concepts proposed by ArianeGroup and RFA. In short, ArianeGroup is betting on a kind of European Starship and RFA proposes a New Glenn with a reusable second stage. The conclusion of the study is that for multiple missions to LEO – also taking into account environmental criteria – launchers with two reusable stages are better, but for higher orbits the ideal are vehicles with two or three stages, but only with the first reusable stage. and the rest disposable. As for fuel, the study considers that the ideal is to use methane in all stages – that is, like Starship – or methane in the first stage and hydrogen in the upper stages – that is, the same as the New Glenn or the CZ-9 —.
ArianeGroup’s proposed launchers can place 100 tons into low orbit. The fully reusable LEO-optimized rocket would use methane in both stages and would have a diameter of 9 meters (like Starship) and a height of 135 meters. The other vector, capable of placing 100 tons in LEO and 35 tons in a geostationary transfer orbit (GTO), would be smaller—100 meters high and 8.5 meters in diameter—despite having the same capacity in LEO thanks to to a disposable hydrogen upper stage. The RFA rockets would both use a first stage of methane and the rest of hydrogen. The two-stage LEO-optimized one could place 80 tons and also 31 tons in GTO, with a diameter of 7 meters—like New Glenn—and a height of 115 meters. The one optimized for GEO would be capable of placing 100 tons in LEO, 50 tons in GTO or, directly, 29 tons in GEO and would be equipped with three stages, the upper two hydrogen, with a height of 135 meters. As for engines, ArianeGroup’s rockets are expected to use the Prometheus or advanced versions of this methane engine, while the powerplant for RFA’s vectors is unclear (the company currently makes the small Helix engines of kerosene of 100 kilonewton thrust).
In ArianeGroup’s fully reusable version the second stage would land vertically similar to the company’s SUSIE proposal. RFA’s proposal would use airfoils similar to those of the New Glenn, but in the second stage instead of the first. All first stages would make use of aerodynamic grilles and deployable landing gear like SpaceX’s Falcon 9. ArianeGroup’s proposal is a combination of the family of methane launchers suggested in recent years with SUSIE, while RFA’s option is more original, although its resemblance to the New Glenn undoubtedly draws attention. Europe is still a long way from developing these launchers, which for the moment are a simple exercise in powerpointism, but this PROTEIN study is a necessary first step. After the delays of the Themis programme, ESA would do well to opt directly to develop a more ambitious heavy launcher – or a medium version of the same – that prevents Europe from being left in the second league of space powers and guarantees the independence of its access to space.
References:
- https://www.aerosociety.com/media/23637/efs-day-2-valere-girardin.pdf
