PARIS — The French space agency, CNES, on Jan. 5 said it has begun a small technology research program with Germany and other governments to develop a future liquid oxygen/methane-powered rocket stage that would be reusable.
Speaking the day before U.S. rocket maker SpaceX was scheduled to attempt to recover the first stage of its Falcon 9 rocket following the launch of a cargo freighter to the international space station, CNES officials said they have not abandoned reusability a decade after starting a joint project with Russia. The SpaceX launch has since been postponed to no earlier than Jan. 9.
That project, called Baikal, has since been shelved as CNES officials concluded that a rocket system with a reusable first stage would need to launch some 40 times a year to make the effort worthwhile.
Michel Eymard, CNES’s director of launchers, said European Space Agency governments in December approved a modest research effort to refine technologies eventually needed to recover, refurbish and reuse an entire Ariane rocket stage.
Reusability is not among the features of Europe’s future Ariane 6 rocket, which is scheduled to make an inaugural flight in 2020. Led by CNES and France, which agreed to finance a 52 percent stake in the project, ESA governments are investing more than 4 billion euros ($5 billion) in the Ariane 6.
CNES worked with various Russian state organizations a decade ago looking for reusable technologies that could be applied to both European and Russian rockets. But Eymard said little came of the effort because of the difficult economics of refurbishing a used rocket stage.
Hawthorne, California-based Space Exploration Technologies Corp. was the principal catalyst for the Ariane 6 program following SpaceX’s first Falcon 9 launch successes and its ability to sell rides aboard that rocket at much less cost than Europe’s current Ariane 5.
Eymard said he had little doubt that SpaceX will be able to recover a Falcon 9 first stage and return it to the factory. The problem is the duration and cost of the refurbishment, he said, and the need to reach a launch rhythm that justifies the work.
“What you have to be able to tell your customers is that the fourth or fifth time you are using the stage will provide the same performance and reliability as its first use,” he said.
Eymard was asked whether CNES is not in the position of having spent two years to catch up to SpaceX with a lower-cost expendable rocket in Ariane 6, only to find that SpaceX has moved to a partially reusable model that cuts costs even further.
“We don’t want to be in the position of appearing to follow in their footsteps all the time,” Eymard said. “But we admire what they are doing and we think it helps put pressure on all of us to do better.”
ESA’s reusable-launcher program is small in size, although when matched with work done by CNES on its own and by the German Aerospace Center, it could produce a consensus on a future technology roadmap by mid-2015. But a vehicle demonstration of the sort SpaceX has planned, he said, will not occur before 2026.
CNES officials have said that in addition to the need for a high launch rhythm, a rocket with a reusable first stage would need to overcome the fact that reusability means reducing the economies of scale realized from producing lots of rocket stages and motors.
The Ariane 6 is designed to carry two telecommunications satellites weighing a combined 9,500 kilograms into geostationary transfer orbit. The vehicle’s cost objective is about 90 million euros ($113 million), or 45 million euros per satellite customer — not far from the current SpaceX price.
CNES President Jean-Yves Le Gall, addressing a briefing here Jan. 5 on CNES’s 2015 plans, said Ariane 6 should be able to be sold commercially at its production cost, which would be substantially better than today’s Ariane 5.
“Today the Ariane 5 is sold for about 150 million euros, but it costs about 170 million euros per launch,” Le Gall said. “European governments make up the difference. These government payments will not be needed for Ariane 6.”
Eymard said the Ariane 6 design, being managed by Airbus Defence and Space and Safran in a newly created joint venture, is already able to launch 10,900 kilograms of payload to geostationary transfer orbit, with enough leftover performance to deorbit its upper stage — a requirement of France’s new Space Law.