(CNN) -- NASA has put off the planned launch of its next-generation Orion spacecraft for a year, a setback to efforts to fly a successor to its aging space shuttles, the space agency announced Monday.
The Orion space vehicle in this artist rendering from Lockheed Martin's web site, won't see space until 2014.
"September 2014 is when we are saying we will launch the first crew on the Orion," program manager Jeff Hanley told reporters in a conference call Monday.
NASA officials plan to wrap up assembly of the International Space Station and retire the space shuttle fleet in 2010, freeing up money to build and fly the new spacecraft. Cost concerns are at the root of the delay, but NASA is also giving itself wiggle room to deal with the unforeseen technical problems that will inevitably crop up, Hanley said.
"It's the unknown unknowns that we have to hedge against," he said. "Having some number of months of schedule flexibility to meet our commitment, in addition to having some number of months of cost -- dollars -- flexibility, is key to keeping ourselves in a healthy posture."
Sometimes called "Apollo on steroids," Orion is designed to ferry astronauts to and from the space station and eventually back to the moon. Unlike the space shuttles, which land like an airplane, Orion is a capsule that will parachute to a landing at Edwards Air Force Base in California. See photos of the full-size mock-up »
The new goal of September 2014 is a year later than NASA had planned to launch the first Orion, but still six months short of the March 2015 commitment date set by Congress. Program managers were hoping to fly the new vehicle much sooner than that to keep the gap between the last shuttle flight and the first Orion flight to a minimum.
"As we looked at the plan we had for September 2013 against the available dollars, it became clear to us that we needed to adjust our schedules," said Hanley.