President Obama will end NASA’s return mission to the moon and turn to private companies to launch astronauts into space when he unveils his budget request to Congress next week, an administration official said Thursday.

The shift would “put NASA on a more sustainable and ambitious path to the future,” said the official, who spoke on condition of anonymity. But the changes have angered some members of Congress, particularly from Texas, the location of the Johnson Space Center, and Florida, the location of the Kennedy Space Center.

“My biggest fear is that this amounts to a slow death of our nation’s human space flight program,” Representative Bill Posey, Republican of Florida, said in a statement.

Mr. Obama’s request, which will be announced on Monday, would add $6 billion over five years to the National Aeronautics and Space Administration’s budget compared with projections last year. With the increase, NASA would receive $100 billion over the 2011 through 2015 fiscal years.