UPDATE 2-Obama budget would cut NASA moon plan

* Companies to take over space taxi flights

* NASA to focus on future technologies for Mars, beyond

* "Death march" for human space flight, senator says

(Recasts and updates throughout with quotes)

By Irene Klotz

CAPE CANAVERAL, Fla. Feb 1 (Reuters) - President Barack Obama is no longer shooting for the moon, with a budget plan that aborts a symbolic but expensive lunar program and spends $6 billion over five years to turn over space transportation to commercial companies.

Some members of Congress immediately promised a fight. One legislator called the plan a "death march' for human space flight. But NASA deployed astronauts and other experts to say the Constellation program, begun under former President George W. Bush to return humans to the moon, was too slow and wasteful.

The space agency's budget would grow to $19 billion in 2011 under the proposed budget released on Monday, with an emphasis on science and less spent on space exploration.

"What this does is open up (space) for more people to be going more places in a way that is not on the back of the taxpayers," NASA's deputy administrator, Lori Garver, told reporters in a conference call.

"The previous trajectory that NASA was on was simply not sustainable," added former astronaut Sally Ride, who served ion a panel that determined Constellation was behind schedule.

"The president's proposed NASA budget begins the death march for the future of U.S. human space flight," said Senator Richard Shelby, the senior Republican on the appropriations subcommittee handling NASA funding.

"Congress cannot and will not sit back and watch the reckless abandonment of sound principles, a proven track record, a steady path to success, and the destruction of our human space flight program," said Shelby of Alabama, whose state is home to NASA's Marshall Space Flight Center.

Florida Senator Bill Nelson has also promised to fight efforts to cut back NASA operations.

MORE COMMERCIAL SPACE OPERATIONS

The new budget extends operations at the International Space Station past its planned retirement date of 2016, suggesting such additions as inflatable space habitats.

Obama's proposal hands over more space operations to the commercial sector, saying it will create thousands of new jobs and hold costs down.

NASA already has spent $9 billion on Constellation and likely would owe millions more to cancel existing contracts. Prime contractors on the Ares rocket program include ATK Launch Systems, Pratt & Whitney Rocketdyne and Boeing Co (BA.N).

Lockheed Martin (LMT.N) is the lead contractor on the Orion capsule.

NASA already has contracts with Space Exploration Technologies and Orbital Sciences Corp to deliver cargo to the station. SpaceX and other firms also are developing spaceships that can carry passengers to orbit and back.

The budget proposes a revamp of the Kennedy Space Center in Florida, where staff have feared major cutbacks, as part of making NASA more efficient.

"A major focus of this effort will be to create the 21st century launch facilities and infrastructure needed at Kennedy Space Center, transforming the facility to more effectively support future NASA, commercial, and other government launches," the budget reads. (Additional reporting by Maggie Fox in Washington, Editing by Vicki Allen and Chris Wilson)