WASHINGTON — Senior NASA officials are open to the idea of canceling the Ares 1 astronaut-launching rocket in favor of outsourcing operations in low Earth orbit to private companies and freeing the U.S. space agency to pursue more-challenging missions that could involve sending humans to close encounters with asteroids or perhaps with the martian moon Phobos, according to officials with the administration of U.S. President Barack Obama.

The so-called Flexible Path option is just one of five presented by a White House-appointed panel tasked with reassessing NASA’s manned space exploration goals. However, during an Oct. 22 press conference marking the delivery of the blue-ribbon panel’s final report to the White House, members clearly emphasized Flexible Path as the most sensible exploration option given NASA’s current funding situation.

The panel, led by former Lockheed Martin chief Norm Augustine, found NASA’s current Constellation program, a five-year-old effort that includes development of the Orion Crew Exploration Vehicle and its Ares 1 launcher, is not sustainable given NASA’s budget and goals. Orion and Ares 1 are intended to replace NASA’s space shuttle; the Constellation program also includes hardware NASA needs to return astronauts to the Moon as currently planned.

During the news conference, Augustine and fellow panelist Edward Crawley, a Massachusetts Institute of Technology professor, described Ares 1 as a “well-managed” program that could overcome technical issues given more money and time.

“It was a wise choice at the time,” said Crawley, referring to former U.S. President George W. Bush’s policy, unveiled in 2004, of replacing the space shuttle and returning humans to the Moon by 2020.

“But times have changed,” said Crawley, who led the panel’s subcommittee that assessed exploration destinations. “The budgetary environment is much more tight, and the understanding of the cost and schedule to develop the Ares 1 has matured.”

The panel found that even under the best of circumstances, Ares 1 and Orion would not be available to transport astronauts to the international space station until 2017, at least one year after NASA plans to de-orbit the laboratory. Even if the administration extends station to 2020, as the committee recommends, the money needed to continue operating the outpost would erode Constellation’s budget, further delaying Ares 1 and Orion to as late as 2019.

NASA Administrator Charles Bolden, Deputy Administrator Lori Garver, and White House science adviser John Holdren are mulling the report as they prepare a recommendation to Obama in the coming months that could reshape the future of NASA’s human spaceflight program.

“NASA is working with the [White House Office of Science and Technology Policy] and other offices in the Executive Office of the President to plan the next steps leading to a decision by the President about future U.S. human space flight plans,” NASA spokesman Michael Cabbage said via e-mail. “It remains premature for anyone at NASA to draw conclusions or speculate about future space flight plans or policies based on the committee’s final report.”

But Obama administration officials say the Augustine panel offered compelling evidence that could lead to a shift in the agency’s manned space exploration goals and approach. To date, NASA has spent nearly $8 billion on the Constellation program, which also  includes the Ares 5 heavy-lift rocket and Altair lunar lander, both being designed by the agency’s Marshall Space Flight Center in Huntsville, Ala.

“The question is not whether NASA can build a vehicle like Ares 1; the question is whether that’s the best use of the nation’s resources, given what we want to do in space,” one administration official said. “That is one of the central issues that has been elevated in the Augustine report.”

Constellation Program Manager Jeff Hanley takes issue with the Augustine panel’s program cost assessments, provided by Los Angeles-based Aerospace Corp. In a Sept. 2 e-mail to Michael Coats, director of NASA’s Johnson Space Center in Houston, Hanley defended his program and outlined potential cost-saving measures.

“We have made clear our many objections with the Aerospace assessment, which was highly superficial and flawed,” Hanley wrote in the e-mail, leaked to media outlets in October. He said the assessment does not “take into account the improvements we have made in our schedule quality and risk posture through deployment of reserves and the reduction of program content.”

Hanley said those changes could save $1.5 billion on the program, which NASA officials maintain is on track for a maiden launch in 2015.

But administration officials are gravitating toward alternatives to Constellation in the Augustine panel’s report, including outsourcing crew transport to low Earth orbit to the private sector.

“There is little doubt that the U.S. aerospace industry, from historical builders of human spacecraft to the new entrants, has the technical capability to build and operate a crew taxi to low-Earth orbit,” the report states, adding that the total estimated cost to NASA of such a commercially developed crew transportation system would be about $5 billion.

“If you look at these scenarios, it may be possible to get a commercial crew capability several years before Ares 1 for less money. And you get to keep space station,” an administration official said.

“We think NASA would be better served to spend its money and its ability, which is immense, focusing on going beyond low Earth orbit rather than running a trucking service to low Earth orbit,” Augustine said during the press conference. “We’ve identified an approach to conducting the spaceflight program that’s somewhat different than the current plan,” he said, referring to Flexible Path.

Crawley said that among the panel’s five options, two of which would continue the Constellation program under different budgetary scenarios, the Flexible Path option makes the most sense.

“What this Flexible Path does is allows you to take some of the components that you would build anyway — the heavy booster and the capsule — and start exploring, while we’re building the lunar lander system and lunar surface system so that when they become available, it’s time to go to the Moon,” Crawley said. “We can leave low Earth orbit in those scenarios … several years earlier than we would otherwise get to the Moon.”

If the White House decides to bypass the Moon and set NASA’s sights on encounters with near Earth asteroids, missions the gravitationally stable Lagrange points and Mars moon flybys, the agency’s choice for a heavy-lift vehicle include a less-capable variant of the Ares 5 Moon rocket. The Ares 5, like the smaller Ares 1, is derived in part from the space shuttle’s solid-rocket motors. Other heavy-lift options could include a system more closely based on the shuttle and a vehicle based in part on hardware used on the U.S. Air Force’s existing Atlas 5 and Delta 4 launchers.

Retired Air Force Gen. Lester Lyles, who led the Augustine panel’s subcommittee on interagency and international integration, said the panel concluded the United States must have a heavy-lift launch capability, regardless of what form it takes.

“We found all the programs to be viable,” Lyles said of the different heavy-lift options during an Oct. 20 luncheon hosted by Women in Aerospace and the Washington Space Business Roundtable here. “There are advantages and disadvantages with any of them, when you look at it. The current program of record, in my opinion, seems to be the right one.”

While noting that an Atlas 5- and Delta 4-heritage vehicle could lower NASA’s operating costs in the long run, the Augustine report said this would be a less-capable vehicle than the Ares 5, adding to mission complexity. In addition, Lyles said modifying the existing Air Force rockets to carry astronauts could be tough to sell to the military.

“They have concerns about human rating [the Atlas and Delta rockets], not from a technical standpoint, but from a program-interruption standpoint for national security space activities.”

Regardless of which heavy-lift option is selected, pursuing the Flexible Path — or any exploration of space beyond low Earth orbit — will require a NASA funding boost beginning in 2011 and gradually building to $3 billion a year above current projections by 2014, according to the report. At that point, the NASA budget would need to keep pace with inflation by rising above the added $3 billion at a rate of 2.4 percent each year, the report found.

“Human exploration beyond low Earth orbit is not viable under the [fiscal] 2010 budget guideline,” the report states, referring to Obama’s $18.7 billion NASA budget request for 2010 that proposes a reduction of more than $3 billion to Constellation in the out-years. Adding funding between 2011 and 2014, on the other hand, would allow NASA to return to the Moon or explore beyond it. “Either could produce significant results in a reasonable timeframe,” the report said.

Internally, NASA has been working for weeks on variously priced options based on the Augustine panel’s preliminary findings. The effort, led by NASA’s Office of Program Analysis and Evaluation, aims to give Bolden and Holdren the data needed to make a recommendation to the president. While the two wait to get on Obama’s calendar later this year, regular discussions are taking place between top NASA leaders and White House staff, and officials are hopeful a decision will be reached before the end of the year. However, more than one administration official has said it is just as likely that a decision won’t be announced before Obama rolls out his 2011 budget submission to Congress in February.

Sen. Bill Nelson (D-Fla.) said in an Oct. 21 floor speech that the president had assured him NASA would get more money for exploration.

“I’ve asked the president to use money from leftover stimulus funds,” Nelson said in prepared remarks. “I’ve also asked him to help minimize the job losses after the space shuttle is retired, in part, by transferring other NASA-related work to Cape Canaveral. He’s assured me that NASA will get enough money to do what it does best: go explore the heavens.”

Other lawmakers are not interested in seeing NASA change course, and have seized on the Augustine committee’s statements that Constellation is a well-run program capable of surmounting technical challenges with more time and money.

“While I look forward to reading the Augustine panel’s final report, Congress has already made its decisions on the issues considered by the panel,” Rep. Gabrielle Giffords (D-Ariz.), chairwoman of the House Science and Technology space and aeronautics subcommittee, said in an Oct. 22 news release. “Now that both internal and external independent reviews have confirmed that the Constellation program is being well executed, we know what needs to be done. Let’s get on with it and cease contemplating our collective navels.”