The launch of NASA's SUV-sized, next-generation Mars rover has been delayed for two years due to continuing technical problems and cost overruns, the space agency announced Thursday.
Originally scheduled to launch late next year, the mission will now take place in 2011, officials said at a media briefing at NASA headquarters in Washington.
"We ran out of time," Charles Elachi, director of the Jet Propulsion Laboratory in La Canada Flintridge, where the rover is being built, said in a phone interview.
The rover, known as the Mars Science Laboratory, is one of the most challenging projects that NASA has ever undertaken.
The craft will carry an instrument payload 10 times heavier than the twin rovers Spirit and Opportunity, which landed on Mars in 2004. Like its cousins, the MSL will be mobile and, with a 43-inch-high deck, will be able to drive right over obstacles that deterred earlier generations of rovers.
The mission is designed to explore the planet's potential for habitability, both now and in the ancient past. A landing site has not yet been chosen, but mission scientists are looking at several sites where orbiting spacecraft have seen evidence of wet conditions.
Because of its large size, the craft employs a complex landing system, which uses a hovering rocket to lower the 2,000-pound rover on a tether as it nears the surface, similar to lowering a piano from an upper-story apartment.
It was a much more mundane set of challenges that forced the delay. Problems developed in the design and operation of 31 actuators -- combination motors and gearboxes that control the mechanical parts of the craft, including the steering mechanism, the robotic arm and the drill that will bore into Martian rocks.
For a time, Elachi said, JPL engineers hoped they could solve the problems and still make the 2009 launch date. But mission managers finally decided they couldn't take a chance with such a complex and costly venture.
"We want to avoid a mad dash to launch," said Ed Weiler, associate administrator for NASA's Science Mission Directorate. "Failure is not an option on this mission."
Elachi said his team at JPL had been fully committed to the 2009 launch date. Engineers "have worked their tails off to make that happen," he said. "Unfortunately we came up a little short."
Because missions to Mars can only launch every two years, when the planet and Earth are in proper alignment, the delay meant the earliest substitute launch date would be 2011.
The delay will increase the cost of the mission from about $1.9 billion to almost $2.3 billion. The extra money will come from other Mars program activities, officials said. They did not specify which ones.
At the briefing, NASA Administrator Michael Griffin was challenged to explain why NASA missions consistently run over budget.
Griffin said each space mission is a new venture that must be designed from the ground up. Asked whether he considered canceling the MSL altogether, he said no.
To do that, "I'd have to believe the project was going badly," he said. "It's not. It's going great."
In the phone interview, Elachi said the delay could have "some minor impact" on the workforce at JPL. He said there would be "a very small number, if any" layoffs, and "we think we can find other work for the majority" of those affected.
Space enthusiasts expressed disappointment over the delay but accepted the need for it.
"Mars exploration has always had its ups and downs," said Louis Friedman, executive director of the Planetary Society in Pasadena.
"But if history has taught us one thing, it is that every setback has been ultimately followed by astounding new accomplishments," he said. "MSL will be worth waiting for."