HUNTSVILLE, Ala. (AP) — The head of NASA says he predicts that humans will walk on another planet in his lifetime, and he challenged an assertion from his predecessor who said that human spaceflight will be grounded until President Barack Obama's administration ends.

NASA Administrator Charles Bolden Jr. made the remark Friday before an audience at Huntsville's Marshall Space Flight Center. The 65-year-old seemed to challenge a remark made hours earlier by his predecessor, Mike Griffin, who said that the Obama administration has no desire to support human spaceflight.

"Despite what you may have heard," said the 65-year-old Bolden, "human spaceflight is not ending."

The Huntsville Times reported that ( ) Bolden offered few details on when the Marshall Center might begin work on the heavy lift rocket, a project held up by budget reviews and internal debates in the White House.

The Obama administration has ceased the shuttle program in hopes of sending astronaut expeditions to an asteroid and Mars. NASA officials say they are retiring the shuttle fleet so the agency can get out of low-Earth orbit and focus on points beyond.

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