American astronauts will walk on the moon again before the end of 2024 “by any means necessary,” Vice President Mike Pence declared on Tuesday at a meeting of the National Space Council.

“It is the stated policy of this administration and the United States of America to return astronauts to the moon within the next five years,” Mr. Pence said at the United States Space and Rocket Center in Huntsville, Ala. On the stage nearby was a model of an Apollo landing module that first transported American astronauts to the lunar surface 50 years ago.

Mr. Pence described a need for NASA to adopt greater urgency in returning to the moon. But an accelerated pace has not been evident in the Trump administration’s NASA budget requests to Congress, raising many questions about how it will be possible for the agency to accomplish this ambitious goal.

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The vice president’s remarks called for changes in the agency’s approach and culture, reflecting frustration within the administration at repeated delays in the development of NASA’s giant rocket, the Space Launch System, and Orion, a capsule for taking astronauts beyond low-Earth orbit to the moon and possibly, eventually, to Mars.