Newly Unveiled Ariane 6 Rocket Design Yields a Few Surprises
PARIS — The French and European space agencies on July 9 disclosed the design of a future Ariane 6 rocket that sacrifices performance on behalf of cost to replace today’s heavy-lift Ariane 5 and medium-lift Russian Soyuz vehicle at Europe’s spaceport starting in the early 2020s.
The vehicle — which as expected leans heavily on solid propulsion, with cryogenics used only on the upper stage — is designed to lift a payload weighing no more than 6,500 kilograms into geostationary transfer orbit, the destination of most telecommunications satellites.
Earlier Ariane 6 designs referred to maximum payload values of 8,000 kilograms to that orbit. More recently, Ariane 6 backers had talked of a 7,000-kilogram maximum, coining the phrase “triple seven” to advertise the vehicle’s basic characteristics: seven years of development, seven metric tons to geostationary transfer orbit and 70 million euros ($93 million) per launch.
Alain Charmeau, chief executive of Astrium Space Transportation, said the 70 million-euro per-launch cost target remains valid, and assumes an Ariane 6 launch cadence of nine to 15 liftoffs per year.
European Space Agency () governments will meet in late 2014 to decide whether to proceed with full development of Ariane 6, an investment that program managers with the French space agency, CNES, say is likely to be between 2.5 billion and 3.5 billion euros over the seven-year period starting in 2015.
In a July 9 statement on the Ariane 6, ESA said the three principal criteria for the rocket were development costs, time to market and operating costs.
The selected design remains the subject of dispute in some government and industry quarters in Europe insofar as it is tilted in favor of solid fuel as opposed to cryogenic fuel.
ESA asked two industrial consortia to analyze rocket designs to compare costs and other criteria as part of a program called New European Launch Service. Both teams concluded that over time the cost of vehicle using two cryogenic-fueled stages was not much different from a vehicle using one cryogenic stage and two solid-propellant stages.
Briefing reporters here July 9, Charmeau agreed that the cost difference between solid and cryogenic technologies was minimal. The choice, he said, was based on other factors.
One of those factors, according to ESA, was the potential synergies with ESA’s Italian-led Vega small-satellite launch vehicle. To the extent that Ariane 6 can borrow from Vega, scale economies might be found to keep Ariane 6 costs within the target, Ariane 6 designers said.
ESA said synergies with Vega development were one of the deciding factors.
The agency said having Ariane 6 use an upper stage similar to what is being built for Ariane 5 Midlife Evolution would save some 600 million euros over the cost of designing a new upper stage. Likewise, the Ariane 6 will employ a 5.4-meter-diameter fairing that is not much different from today’s Ariane 5 fairing.