The replacement for the Ariane 5 rocket after 2020 will likely be smaller and less expensive to meet the needs of lighter European Space Agency missions, according to the head of the agency’s launcher program.
“The fact that we want launchers that serve our institutional missions means that we need a smaller launcher than Ariane 5, it being understood that Ariane 5 could serve the space station with ATV and launch exploration missions,” said Antonio Fabrizi, ESA’s director of launchers.
The Ariane 5’s most powerful version can lift more than 21,000 pounds to geosynchronous transfer orbit and more than 44,000 pounds to low Earth orbit.
There are few individual ESA or commercial payloads capable of filling the Ariane 5’s capacity, so Arianespace launches pairs of communications satellites on most of its flights.
One exception is the Automated Transfer Vehicle, a major ESA contribution to the International Space Station. The ATV weighs more than 42,000 pounds at launch, nearly maxing out the Ariane 5’s capabilities.
The first ATV, named Jules Verne, delivered supplies to the station last year. At least four more ATV’s are scheduled to fly through 2015.
But officials do not foresee many other payloads taking advantage of the Ariane 5’s heavy-lifting capacity, unless ESA launches more ATV’s, develops a human space transportation system, or takes a significant role in deep space exploration, Fabrizi said.
Ariane 5’s prognosis may largely depend on policy decisions in the United States, especially on exploration and human spaceflight topics now being reviewed by leaders at NASA and in the White House.
ESA and NASA have been trending toward closer cooperation than ever before in recent months, including agreements on a combined Mars program, space transportation and discussions of an Earth sciences partnership.
“I’m not saying that Ariane 5 may be out of scope for us at all. On the contrary, but we have to think of what is best for us in the long term,” Fabrizi said.
The outlook for ESA institutional missions, mostly science payloads, will determine the size of the Next-Generation Launcher, as the program is officially named.
“We look particularly at what we need for our institutional missions. Ariane 5 is not the most-used by us, so we would like a launcher that is better suited for the European institutional missions,” Fabrizi said.
The commercial viability of a rocket is a secondary concern.
Jean-Yves Le Gall, chairman and CEO of Arianespace, declined to comment in detail on the Ariane 5’s long-term future in an interview with Spaceflight Now.
“Today it is just a preliminary thought and I do not want to comment more than this because there is a very big spectrum of ideas,” Le Gall said.
ESA is studying configuration options and consulting the agency’s member states before potentially deciding on requirements for the new rocket.
The Ministerial Council, consisting of representatives of ESA member nations, gave support to the agency’s Future Launch Preparatory Program during a meeting last November.
Officials are now soliciting input and ideas from the ESA’s 18 member states, specifically France, Germany and Italy, according to Fabrizi.
“Looking at the scenarios after 2020 or 2025, we have to think what the demand for launchers will be. We have a roadmap that should lead to to the next Ministerial (Council) in the coming years,” Fabrizi said.
“This roadmap starts with the delegations of our member states to discuss different scenarios and different requirements and what is the mission we want to give this new family of launchers,” Fabrizi said.
ESA has also signed contracts for a high-thrust engine demonstrator that could be used on the new rocket.
The alternatives under review include configurations with solid and liquid propulsion, various numbers of stages and strap-on boosters.
“We have tradeoffs ongoing on different types of propulsion and staging. I think if we look at the long term evolution of the ESA family of launchers, we may think of Vega 2 and Ariane 6. But these are just names,” Fabrizi said.
Prospects for a reusable launcher have been shelved due to concerns with technology development and high costs. ESA still plans to launch a small reusable re-entry demonstrator in 2012, and most of that mission is already funded.
In the meantime, officials are studying plans to install a more powerful and more reliable upper stage on the Ariane 5 by about 2016.
The upgrade would include the Vinci engine, a brand new power plant that would replace the Ariane 4 heritage HM-7B engine used on the Ariane 5’s ECA upper stage.
The Vinci could allow the Ariane 5 to deliver cargo directly into geosynchronous orbit, cutting the amount of fuel satellites have to carry.
Officials expect decisions on both the evolution of Ariane 5 and a future replacement in 2011.
[Stephen Clark, SpaceFlightNow, 17/10/2009)