WASHINGTON — U.S. President Barack Obama sent Congress a $19 billion NASA budget proposal Feb. 1 that cancels his predecessor’s Moon-bound Constellation program, commits to operating the international space station through at least 2020, and invests billions of dollars in commercial space vehicles and “game-changing technologies” intended to put the United States on a sustainable space exploration footing.

“This new path is a big change. I realize that,” NASA Administrator Charles Bolden told reporters during a Feb. 1 teleconference. “But it is not a change from the guiding principles of NASA. It makes America stronger. It enables us to draw more strongly on the ingenuity of the commercial sector and create deeper ties with our international partners.”

After reading his 10-page opening statement, Bolden left the teleconference before taking questions from reporters. That job fell to NASA Deputy Administrator Lori Garver, NASA Chief Financial Officer Beth Robinson and Jim Kohlenberger, chief of staff of the White House Office of Science and Technology Policy.

“We are canceling Constellation. We are not canceling our ambitions to explore further and farther into space,” Kohlenberger said.

“This isn’t a step backwards,” he continued. “I think the step backwards was trying to recreate the Moon landings of 40 years ago really largely using some of yesterday’s technology instead of game-changing technologies that can take us further, faster and more affordably into space.”

While U.S. lawmakers representing states and congressional districts with heavy stakes in the Constellation program swiftly condemned Obama’s plan as the end of human spaceflight, Kohlenberger and Garver defended the changes as necessary to putting the program on a sustainable footing.

“Keep in mind we found out during the Augustine review that we weren’t going to the Moon in 2020,” Garver said, referring to the review of U.S. human spaceflight plans called for last year by the White House and led by former Lockheed Martin chief Norm Augustine. “The Augustine report made it clear that we wouldn’t have gotten to beyond low Earth orbit until 2028 and even then would not have the funding to build the lander. So we had lost the Moon, and what this program does is give us back the solar system.”

While NASA’s new plan does not set a firm date for fielding a heavy-lift launch vehicle or conducting the first human missions beyond low-Earth orbit since the Apollo Moon program ended in 1972, it does commit several billion dollars over the next five years to developing breakthrough technologies intended to make space exploration faster and more affordable.

“Imagine trips to Mars that take weeks instead of nearly a year, people fanning out across the inner solar system, exploring the Moon, asteroids and Mars nearly simultaneously in a steady stream of ‘firsts,” Bolden said. “And imagine all of this being done collaboratively with nations around the world. That is what the president’s plan for NASA will enable, once we develop the new capabilities to make it a reality.”

NASA has spent $9 billion on Constellation since the program was created in response to then-President George W. Bush’s 2004 Vision for Space Exploration speech.

Pulling the plug on Constellation and its three early elements — the Orion Crew Exploration Vehicle, its Ares 1 launcher and the Ares 5 heavy-lift rocket — is expected to cost NASA about $2.5 billion in contract termination penalties and other program-closeout-related expenses, according to NASA budget documents.

Kohlenberger said sunk cost is no reason to continue a program that is unsustainable.

“The fact that we poured $9 billion into an unexecutable program really isn’t an excuse to pour another $50 billion into it and still not have an executable program. I think that’s what I’d tell taxpayers,” Kohlenberger said. “Instead we are going to make wise, prudent investments — an additional $6 billion over the next five years — to really propel us on a new journey of exploration and discovery.”

Of the $4.26 billion NASA is seeking for exploration in 2011, $1.9 billion is budgeted for closing out the Constellation program, with another $600 million for closeout costs budgeted for 2012.

Garver said NASA hopes to be able to use some of the Exploration Systems Mission Directorate’s 2010 budget to cover some of the Constellation closeout costs. “That would be the preferred method, but we have to work with Congress to do that,” she said.

In approving NASA’s 2010 budget late last year, Congress imposed restrictions intended to prevent NASA from canceling Constellation contracts this year without formal legislative approval.

In place of building Orion and the Ares family of rockets, NASA now intends to spend $6 billion over the next five years fostering development of commercially operated systems capable of ferrying astronauts to and from the international space station.

Obama’s plan covers the new investment in part by increasing the agency’s budget by a like amount over the next five years. NASA’s 2011 budget, however, would rise just $276 million, or 1.47 percent over this year’s level.

NASA also has budgeted $3.1 billion over the next five years for a Heavy Lift and Propulsion Technology program focused on first-stage propulsion, in-space engines and basic propulsion research conducted in cooperation with other government agencies and commercial and international partners, Robinson said. NASA intends to kick off the program in 2011 with $559 million.

NASA is also seeking $652 million for 2011 to begin a technology demonstration effort largely focused on so-called flagship-class projects costing between $500 million and $1 billion apiece to demonstrate breakthrough capabilities such as in-orbit refueling and propellant storage and autonomous rendezvous and docking, Robinson said.

NASA’s exploration budget also includes $3 billion over the next five years for a revitalized robotic precursor program that Garver said would include a lunar lander mission. Funding would start at $125 million in 2011 and ramp up quickly from there, topping $900 million annually by 2015.

NASA already is subsidizing development of two rival cargo delivery systems under the $500 Commercial Orbital Transportation Services demonstration program begun in 2006 and $3.5 billion worth of Cargo Resupply Services contracts awarded in late 2008. The two recipients of that funding, Dulles, Va.-based Orbital Sciences Corp. and Space Exploration Technologies (SpaceX) of Hawthorne, Calif., expect to demonstrate their systems in 2010 and 2011, respectively.

SpaceX has said it could field a crewed version of its Falcon 9-launched Dragon capsule within three years of receiving funding.

Garver said that at least one large aerospace company has said it could put a crewed system into service even faster than that.

For planning purposes, though, Garver said NASA expects a commercial system to be ready to go in 2016, a year or two years earlier than the Augustine committee concluded Ares 1 and Orion could be ready.

Bolden said during his introductory remarks that NASA would “set standards and processes” to ensure that the envisioned commercial vehicles are safe.

“I lost friends in two space shuttle tragedies, so I give you my word these vehicles will be safe,” Bolden said.

NASA expects to release more details in the coming weeks and months about how it intends to structure its commercial crew program.

Before leaving the call, Bolden made a long-expected announcement about the winners of $50 million in so-called Commercial Crew Development money NASA put out for bid last year. He said Kent, Washington-based Blue Origin, Houston-based Boeing Co., Tucson, Ariz.-based Paragon Space Development Corp., Louisville, Colo.-based Sierra Nevada Corp., and Denver-based United Launch Alliance had been awarded Space Act Agreements for the development of crew concepts, technology demonstrations and studies.

Brian Berger is editor in chief of SpaceNews.com and the SpaceNews magazine. He joined SpaceNews.com in 1998, spending his first decade with the publication covering NASA. His reporting on the 2003 Space Shuttle Columbia accident was...