The European Space Agency will supply the service module that will power an initial unmanned test flight of NASA's Orion deep space exploration capsule in 2017 and provide components for a second, manned mission in 2021 under an agreement discussed Wednesday at the Johnson Space Center.
The service module, which will provide propulsion, electrical power, thermal control and life support system components and supplies, will be based on the design of ESA's Automated Transfer Vehicle, an unmanned supply ship that has completed three flights to the International Space Station.
The solar-powered service module will be located just behind the Orion crew capsule, between the spacecraft heat shield and the launch vehicle. NASA will supply the critical load-bearing interfaces and will contribute space shuttle orbital maneuvering system engines for the propulsion system.
"We put them in the critical path," said William Gerstenmaier, NASA's director of spaceflight operations at agency headquarters. "We probably wouldn't have done that without the experience we've had in space station."
Depending on how the cooperative venture goes from a technical perspective -- and assuming continued political support and funding -- NASA and ESA could agree to additional joint flights or pursue modified objectives.
But in the near term, officials say, the agreement will help both parties transition from work in low-Earth orbit to deep space operations ranging from flights back to the moon, to nearby asteroids and, eventually, to Mars.
"To me, the essential part of this is not whether we've accelerated something or not, it's actually initiating international partnership beyond low-Earth orbit, that's really the key," said Mark Geyer, NASA's Orion program manager.
Gerstenmaier agreed, saying the agreement "allows us to work smarter within the contracts we have to make sure we're going to get to those dates of 2017 and 2021 with more robustness."
"We shouldn't try to go look at what ESA's contributing and then try to subtract that out of our budget. We're actually getting a better, more robust design by cooperating together."
Thomas Reiter, a veteran ESA astronaut who serves as that agency's director of human spaceflight and operations, declined to provide funding details other than to say the overall cost to ESA is expected to be in the range of $600 million ($450 million euros).
"This is a remarkable moment for ESA," he said. "We are opening a new page in trans-Atlantic cooperation for ESA, being involved in the building of a space transportation system (that) will give a perspective for humans to go beyond low-Earth orbit.
"Certainly, low-Earth orbit will remain a destination for us, we have a fantastic infrastructure in orbit. ... But another aspect is, of course, to bring humans beyond low-Earth orbit to new destinations. And this cooperation brings us into this endeavor."
Under the direction of the Obama administration, NASA is implementing a two-tiered approach to post-shuttle manned space operations.
The agency is funding a competition to develop private-sector spacecraft to ferry astronauts to and from the International Space Station on a commercial basis. At the same time, NASA is developing the Orion capsule and a new heavy-lift Space Launch System booster for government operated flights to a variety of deep space destinations.
Using a United Launch Alliance Delta 4 rocket, an unmanned Orion is scheduled for the program's maiden launch in 2014. Known as Exploration Flight Test 1, the objectives of the initial mission are to propel the Orion capsule to an altitude of 3,600 miles, setting up a high-speed re-entry and heat shield test.
Exploration Mission 1, also unmanned, is targeted for launch in late 2017 using an initial version of the planned Space Launch System booster. Preliminary plans call for a weeklong mission to the vicinity of the moon and back.
If all goes well, the first manned mission, EM-2, would follow in 2021 with another round-trip flight to the moon.
"EM-1 and EM-2, at this point we conceptually talk about them going to the vicinity of the moon," Gerstenmaier said. "We're still looking at what the details are and what we want to go really do with those missions."