France's independent state auditor, the Cour des comptes, has raised concerns about the viability of Europe's new rocket, the Ariane 6 launcher. In its 2019 annual report, the auditor said the France-based launch company Arianespace is also being too cautious as it grapples with competitors like the US-based SpaceX.

"In 2017, Arianespace lost global leadership in the commercial market to the American company SpaceX," the report finds. "This competitor's business model is based on the breakthrough model of reusable rockets."

The report discusses the potential for further losses of market share and revenues against the rise of competition from SpaceX and a global dip in demand for the launch of commercial satellites to geostationary orbit. It also criticizes the choices European leaders made in 2014, when they selected the design for its next-generation rocket, the Ariane 6. This booster may fly for the first time in 2020 from the European spaceport in Kourou, French Guiana.

"This new launcher does not constitute a sustainable response in order to be competitive in a commercial market in stagnation," the auditor's report states. The Ariane 6 rocket design is too "cautious," according to the report, relying on mostly traditional technologies.

The Ariane 6

Last year, officials with Ariane Group told Ars that Ariane 6 has been optimized for quicker launch and lower costs. The core stage of the Ariane 6 launcher may appear similar on the outside to the existing Ariane 5 rocket, but the components inside are completely different. At every step, Arianespace has sought to reduce the hours of manufacturing, the cost of the materials, and complexity of the system.

The Ariane 6 has two primary variants. The Ariane 64, with four solid rocket boosters, will serve larger payloads—up to 11.5 tons to geostationary transfer orbit. The smaller Ariane 62, with two solids, will have about half of this capacity but cost less.

If everything works, when the Ariane 6 debuts, it will offer comparable service to the Ariane 5 rocket at a 40 to 50 percent reduction of cost. It will not be reusable, of course, and it can never reach the theoretically super-low cost of a fully reusable Falcon 9. But having eight to 10 launches a year, from an economic standpoint, simply does not justify the expense of developing and flying a reusable rocket, European officials said.

What business model?

SpaceX has benefited from "huge financial support" from the US government, the report asserts, but it also praised the company's "breakthrough model" of reusability. (This "huge financial support" argument is based on NASA funding for the development of the Falcon 9, which was limited, and a European belief that the US military artificially inflates the amount it pays SpaceX for satellite launches. In reality, SpaceX's Falcon 9 rocket has driven down the price of military launches).

By contrast, France has shouldered half of the €4 billion ($4.5 billion) cost of developing the Ariane 6 launcher, with the remainder coming from other European countries. The new rocket gives greater responsibility to manufacturers, which should allow them to reduce costs. But the declining number of commercial customers, price competition from SpaceX as well as other market entrants including Blue Origin, and lack of technical innovation mean that Ariane 6 risks being competitive in the long term regardless.

The report makes half a dozen recommendations. For example, any new public funds committed to rocket development should be spent on "technical innovation," rather than supporting existing contractors.

Overall, this is a critical report, but it seems unlikely to effect that much of a change. Previously, European leaders, including French President Emmanuel Macron, have stated that they want the continent to maintain its own independent access to space. So the Ariane 6 is likely to fly for a long time, whether it is commercially viable on its own or, as this report suggests may happen, requires subsidies to break even.