Germany trades P120 booster production for Ariane 6 turbo pumps, upper stage carbon fiber research

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WASHINGTON — European Space Agency member states have agreed to keep all production of P120 solid rocket boosters in Italy instead of opening a second production line in Germany.

Germany will instead produce turbo pumps for the upcoming Ariane 6 rocket and redirect its P120 funds towards technology maturation work on a carbon fiber upper stage that could give Ariane 6 another 1,000 kilograms of lift capacity.

The compromise, reached during a May 17-18 meeting of the ESA launcher program board in Frascati, Italy, puts to rest the controversial division of P120 production. The 2016 decision, while popular in Germany, was viewed unfavorably in Italy.

The P120 serves as the first stage of the Vega C rocket and will be used as a strap-on booster for the Ariane 6 heavy-lift rocket. Vega C, like the standard Vega rocket used today, is built almost entirely in Italy. Ariane 6 production, in contrast, is spread more broadly across France, Germany and other ESA member states who pay for the launcher’s development and use.

“The production of the P120 will be done in its full capacity in Italy,” Daniel Neuenschwander, ESA’s director of space transportation, told SpaceNews May 24. In addition, some 70 million euros ($80.8 million) in German funds originally slated for the second production line are being repurposed for a potential carbon fiber upgrade to the Ariane 6 upper stage. ArianeGroup CEO Alain Charmeau, said the upgrade, still under consideration for implementation, wouldn’t be incorporated until at least 2025 — five years after Ariane 6’s scheduled maiden flight.

The German division of Ariane 6 prime contractor ArianeGroup will build the turbo pumps previously supplied by Vega C prime contractor Avio, Neuenschwander said. Avio declined to comment on the transfer of production responsibilities.

MT Aerospace, a subsidiary of German space company OHB, was preparing to run the second P120 manufacturing line in 2021 or 2022 using a carbon fiber production method it said was more cost-effective than Avio’s technique. Neuenschwander confirmed the 70 million euros will go toward validating “technology prework which has been done on carbon fiber activities” by German industry.

Charmeau told SpaceNews his company is working with MT Aerospace on implementing carbon fiber cryogenic tanks and other structures for the Ariane 6 upper stage. Redesigning metallic structures with carbon fiber would result in a lighter stage, enabling the rocket to carry heavier payloads to orbit, he said.

“We target at least a one-ton performance increase,” he said. The improved upper stage would have its first flight between 2025 and 2030, depending on budget provisions from ESA, he said.

“One kilogram saved on the inner structure of the upper stage is a direct additional kilogram for the payload, one to one, so by using carbon fiber structures we will reduce the weight of the upper stage and therefore increase the capability for the payload,” he said.

The upper stage upgrade would increase maximum Ariane 6’s lift capacity to 13,000 kilograms, roughly 12 percent more than the heaviest Ariane 5 launch performed to date.