WASHINGTON — NASA will not be getting the $1 billion budget boost civil space advocates had hoped to see when President Barack Obama sends his 2011 spending proposal to Congress Feb. 1, requiring the U.S. space agency to make even tougher than expected choices about the future of its manned space program, according to sources with close ties to the administration.

These sources declined to reveal the fate of NASA's planned Ares I crew launch vehicle, which many observers see as a likely cancellation target, but they did say the budget proposal would fund a multibillion-dollar effort to foster development of commercial systems for ferrying astronauts to the International Space Station.

An independent panel concluded this past summer that NASA could not afford to develop the Ares I and a crew carrying capsule dubbed Orion without a significant budget increase, which the sources said is not in the offing for 2011

Meanwhile, Obama will request budget increases for environmental satellites, education programs, and research and technology development, these sources said.

NASA's budget, just over $18.7 billion this year, is still expected to rise again in 2011, though by much less than the $1 billion increase NASA and its contractors have been privately anticipating since mid-December, when Obama met with NASA Administrator Charles Bolden to discuss the findings of a White House-appointed panel tasked with assessing alternatives to the agency's plan to replace the space shuttle with Ares I and the Orion Crew Exploration Vehicle and build a heavy-lift rocket and the rest of the hardware needed to put astronauts on the moon for extended stays. The panel, led by former Lockheed Martin chief Norm Augustine, urged the administration to consider abandoning Ares I in favor of relying on the private sector to transport astronauts to the space station. The panel also said a worthwhile manned space exploration program would require Obama to budget about $55 billion for human spaceflight over the next five years, some $11 billion more than he included in the 2011-2015 forecast he sent Congress last spring.

Commercial crew launches

While Obama's funding proposal deviates from the Augustine panel's push for a spending increase, sources said NASA's 2011 budget request is expected to align with the panel's so-called Flexible Path plan that includes scrapping long-duration moon missions in favor of shorter visits to a variety of destinations in the inner solar system, including near-Earth asteroids and eventually Mars.

Other hallmarks of the Augustine panel's Flexible Path approach that will be evident in the president's 2011 budget include abandoning the Ares I launcher and funding commercial development of rockets and spacecraft designed to ferry astronauts to and from the space station. Although the Augustine panel found Ares I to be a "well-managed" program capable of overcoming technical problems given additional money and time, it questioned whether it was still the right vehicle for NASA to be developing.

"The central question is not whether can NASA build the Ares I ... the question is should NASA build the Ares I," Augustine panel member Edward Crawley said during last October's unveiling of the final report.

While the report stopped short of calling for canceling Ares I, it included the crew launcher in just two of the eight options it laid out for NASA's human spaceflight program. Both scenarios entailed de-orbiting the space station in 2015 — at least two years before Ares I would be ready to fly — and delaying the start of human lunar missions by five years to 15 or more years, depending on how much additional money NASA would get.

"It was a wise choice at the time but times have changed," Crawley said last October, referring to Ares I and rest of the Constellation program NASA designed in response to a 2004 presidential mandate to retire the shuttle and return humans to the moon by 2020. "The budgetary environment is much more tight, and the understanding of the cost and schedule to develop the Ares I has matured."

Every option the Augustine committee presented the Obama administration for keeping the space station in service through 2020 — something the United States' international partners are counting on — while sending humans beyond low Earth orbit within the next decade or so also assumed NASA would rely on commercial crew systems for getting astronauts to the station.

At the same time, the Augustine panel suggested NASA continue developing Orion for exploration missions and to serve as fallback option should commercial crew systems fail to materialize.

Long-brewing budget trouble

Developing Ares I is costing NASA more than it originally projected, yet the rocket's schedule has continued to slip since the program's inception.

Budget data available on NASA's Web site indicate Ares I, part of a broader, 5-year-old effort to replace the space shuttle with new rockets and spacecraft optimized for the moon, is over budget by almost half a billion dollars.

In addition, independent estimates suggest Ares I and its Orion Crew Exploration Vehicle would not be ready to launch astronauts until 2017, three years later than the goal then-U.S. President George W. Bush set in his 2004 Vision for Space Exploration speech and six years later than the more aggressive target then-NASA Administrator Mike Griffin set the following year.

In hindsight, NASA officials say the agency set Ares I and Orion on an unsustainable spending trajectory, signing contracts to develop the rocket and crew capsule on a schedule that the agency's projected budget did not support and forcing unpopular cuts to other NASA programs in an effort to keep Ares and Orion on track.

When Bush called in January 2004 for retiring the space shuttle and returning humans to the moon by 2020, the broad outlines of the plan were already incorporated in the 2005 budget request he sent to Congress the following month. A presidential commission established to make recommendations on implementing the Vision for Space Exploration did not deliver its report until preparation of NASA's 2006 request was underway. NASA officials say those early budgets funded a hastily cobbled together program that failed to fully encompass Bush's vision.

"The Vision and those budgets covered a rather incomplete program that was largely the Crew Exploration Vehicle with minimal operations, launch vehicle costs and program integration," said Andrew Hunter, a budget official in NASA's Exploration Systems Mission Directorate who oversees spending for the agency's Constellation program, which in addition to Ares I and Orion includes the Ares V heavy-lift rocket and Altair lunar lander.

Delays and more delays

Hunter said that while the lunar portion of the program was not clearly defined at that time, "the overall goal per the Vision was to have the crew exploration vehicle operational by 2014."