NASA will get nearly $6 billion to encourage private companies to launch their own spacecraft under the budget proposed by the Obama administration Monday.

A vapour cone forms around the Ares I-X rocket during liftoff Oct. 28, on a sub-orbital test flight from the Kennedy Space Center in Cape Canaveral, Fla. (Chris O'Meara/Associated Press) U.S. President Barack Obama's budget would cut NASA's planned mission to the moon, called the Constellation program, which Obama called "over budget, behind schedule and lacking in innovation."

NASA has already spent $9 billion on the Constellation program, which began after the 2003 shuttle accident, including the test launch of the Ares 1-X rocket in October.

The budget would provide $5.9 billion to the agency over the next five years to fund private space-flight companies.

The budget's commitment to NASA is $100 billion over the next five years.

Under the plan, NASA would pay the companies to carry U.S. astronauts to the International Space Station and other destinations in orbit.

NASA would then be a guaranteed customer for the private space companies through 2020. Proponents of private space flight point out the parallel with the early days of air travel, when private airlines had a guaranteed customer in the U.S. government to deliver airmail.

Stronger space industry could create jobs

A White House budget statement said, "A strengthened U.S. commercial space launch industry will bring needed competition, act as a catalyst for the development of other new businesses capitalizing on affordable access to space, help create thousands of new jobs and help reduce the cost of human access to space."

The budget also calls on NASA to research future heavy-lift rocket systems that would send humans "farther and faster into space."

It also gave a funding boost to the International Space Station, extending its operation until at least 2020.

Proponents of private space travel hailed the NASA budget announcement.

"With a $6-billion program, you can have multiple winners. You'll literally have your BlackBerry, your iPhone and your Android phone all competing for customers in the marketplace," said John Gedmark, executive director of the Commercial Spaceflight Federation.

However, the Aerospace Safety Advisory Panel warned that current private spacecraft haven't been tested by the government as safe for human travel. The panel said this would have to be addressed before NASA could move to commercial space flights for its astronauts.

The U.S. Federal Aviation Administration does have a commercial space division, so it would regulate the safety of private spacecraft.

The process for testing private spacecraft hasn't been spelled out, though, said former NASA associate administrator Scott Pace, now a space policy professor at George Washington University.

Congress supports status quo

Pace said efforts by former president Bill Clinton to privatize parts of the government agency that builds and operates spy satellites failed, and privatizing human space flight could face a similar fate.

The current space program has strong support in Congress, and any change could be difficult to push though.

Peter Diamandis, founder of the X Prize Foundation, which sponsors a space flight competition, says the safety of commercial space isn't an issue in his mind.

"We don't fly on U.S. Air Government. We fly on Southwest and JetBlue," he said.

Already, much of the U.S. space program involves private companies. The space shuttles were built by Rockwell International and day-to-day operations of the shuttle were privatized in 1996.

The leading companies in private space flight include aerospace giants Boeing and Lockheed Martin, as well as newer companies such as SpaceX, which already has its Falcon rocket and Dragon capsule, Orbital Sciences, Bigelow Aerospace, and Sierra Nevada Corporation.

One early entrant in the private space flight market is Virgin Galactic, whose SpaceShipTwo was unveiled in Mojave, Calif., in December by billionaire Richard Branson, in an expensive gamble on space tourism. (Phil McCarten/Reuters) With files from The Associated Press