PARIS — Astrium says it has completed a series of tests proving that key design and production processes used to manufacture Europe’s Ariane 5 launcher can support production of the Liberty transportation system, one of a handful of proposals vying for NASA development funding under a third round of commercial crew transportation awards the agency will announce this summer.

Led by Alliant TechSystems (ATK), Liberty is based on a combination of hardware from NASA’s defunct Constellation program, including the five-segment solid-rocket booster developed for the Ares 1 rocket and a composite space capsule based on the Orion Multipurpose Crew Vehicle.

Astrium Space Transportation is providing the Liberty second stage based on the liquid-fueled cryogenic core of the Ariane 5, which is powered by the Snecma-built Vulcain 2 engine. With 48 consecutive successful missions over nearly nine years, the rocket is arguably the world’s most reliable launcher.

Kent Rominger, Liberty program manager for Magna, Utah-based ATK, said the tests demonstrate Liberty’s industry team can keep the program on schedule for a planned first test flight in 2014 followed by a crewed flight in 2015.

“To stay on my schedule, I’ve got to do this. If I don’t get a NASA award, my schedule slips way out, but we [at] ATK have been investing, our partners have been investing, because we know one of the things that’s important is we want to start launching astronauts from the United States, rather than sending them over to Baikonur to launch on a Soyuz.”

Silvio Sandrone, vice president of business development for launchers at Astrium Space Transportation, said the trial shows that existing manufacturing processes are capable of machining, forming and welding the thicker, stiffer cryogenic tanks necessary for the Liberty second stage.

The two-stage Liberty rocket was first proposed in 2011 as a contender for NASA’s commercial crew program, an initiative that seeks to privatize astronaut transportation to and from the International Space Station in the post-space shuttle era. Rominger says the ATK and Astrium team could provide astronaut rides to and from the ISS for considerably less than the $62 million per seat that Russia currently charges for crew transportation aboard Soyuz spacecraft. NASA rejected the initial Liberty bid in part because ATK and Astrium had no commitments by crew-vehicle developers interested in launching atop the proposed rocket.

In September 2011, ATK and Astrium said they would continue Liberty’s development under an unfunded Space Act Agreement with NASA. Under the terms of the agreement, the U.S. space agency provides engineering and other technical support to industry through mid-July, when a third round of commercial-crew development awards is expected to be announced.