It's hard to know which is bigger these days, NASA's problems or its plans.
It has been a year since the space shuttle Columbia broke up in the atmosphere over Texas, and today, more than ever, the U.S. space agency faces an uncertain future.
Will it soar to reach exciting new goals of manned journeys to the moon and to Mars?
Or will it sink under the weight of unsafe vehicles, unrealistic expectations and lack of money?
The shuttle fleet is 40 percent destroyed _ two of five vehicles have been lost _ and 14 shuttle astronauts have died. The three remaining orbiters _ Endeavour, Discovery and Atlantis _ are grounded while NASA struggles to meet tough new flight standards imposed after the Columbia tragedy.
NASA wants to launch Atlantis on Sept. 12 to continue assembly of the international space station and to test new shuttle safety hardware and procedures. Few experts, however, expect them to make that date.
It's a long shot, according to the panel appointed to monitor the agency's compliance with new safety standards recommended by the CAIB _ the Columbia Accident Investigation Board.
"It is still much too soon to predict either the success of implementation (of new safety standards) or the timing of the next flight," the panel reported on Jan. 20. "As time passes and the interval before the next scheduled flight diminishes, the enormity of the remaining task looms."
But in the midst of the gloom and doubt about the shuttle's future, President Bush stepped up to promise the moon and Mars.
"We will give NASA a new focus and vision for future exploration," he said on Jan. 14. "We will build new ships to carry man forward into the universe, to gain a new foothold on the moon, and to prepare for new journeys to worlds beyond our own."
But the president sketched out a vague schedule and promised little money for what eventually would be a stupendously expensive and hazardous venture.
"It seems to me that it's either a great way to raise the space program up, or to bury it," said David Baker, editor of Jane's Space Directory and a former 20-year employee and consultant for NASA. "The goals aren't attainable if there's no money in the budget to pay for it."
When George Bush, the current president's father, outlined a similar program during his presidency, cost estimates came back at between $400-billion and $500-billion. Congress promptly lost interest.
"I'm very concerned about the long term affordability of such a project (a Mars mission)," said Baker, "and meanwhile NASA will retire its only means of putting men in space, of getting people to the space station, years ahead of development of the next human flight vehicle."
John Logsdon, director of the Space Policy Institute at George Washington University and a member of the CAIB, said he welcomed the president's announcement.
"To fly the shuttle beyond 2010 it would have to be recertified, and we (the CAIB) weren't convinced it would pass recertification in 2010. But without it, NASA lacked a long-term mission. The White House took care of that with the moon and Mars initiative."
According to Bush's plan to reorganize the space agency, the shuttle fleet would complete work on the international space station by 2010 and then be shelved.
NASA hopes to fly about 23 missions before 2010 _ eight to finish the U.S. portion of the space station, and at least 15 more to finish assembling the parts contributed by partners such as the European Space Agency.
To get started, NASA wants to launch twice before the end of this year, beginning with Atlantis in September. First, however, the agency must make certain that the remaining three shuttles can meet safety standards and that the crews can deal with problems such as the one that claimed Columbia, a damaged heat-resistant panel on leading edge of the vehicle's left wing.
NASA officials say they can do it.
"There's not a showstopper that says we can't get there," said Michael Kostelnik, NASA's deputy associate administrator, in a telephone news conference last week.
John Pike, the blunt, longtime observer of the space program for the Federation of American Scientists, agreed. Pike, now director of the nonprofit, nonpartisan Web site globalsecurity.org, says there is no real reason NASA can't fly the 23 or so missions necessary to complete the space station. But the public should not think the three remaining shuttles will ever be safe, he said.
He also noted that the Columbia investigation board produced recommendations, not orders, and that NASA Administrator Sean O'Keefe has said that he will decide when the shuttle is safe enough to fly.
To some it already sounds like NASA is feeling pressure to hurry again, a mistake that got the agency in trouble with Columbia a year ago and Challenger in 1986.
"NASA always seems to pick up pressure from someplace to move fast. Now there will be pressure from industry to get the shuttle flights over with and to put the space station behind, so they can move on to the next big projects _ Mars and the moon."
Baker said he doubts NASA's ability to meet even its short-term goal of getting the shuttle flying regularly again.
"If everything works I suppose it is achievable," he said, "but it's a very bold plan _ especially since it involves a vehicle designed 40 years ago, a vehicle that would not be certifiable for space flight today.
"This vehicle," he said, "continues to surprise."
The plans to make the shuttle safer
Columbia broke up during re-entry as it headed for a landing at Kennedy Space Center. The cause of the accident was a breach in the reinforced carbon panels on the left wing, which occurred when a piece of insulating foam from the external tank hit the panel during liftoff on Jan. 16.
Engineers are trying to come up with a way to repair both the heat-resistant tiles on the underside of the vehicle, and the panels on the leading edge of the wings.
The ability to do on-orbit repair was one of five recommendations from the the Columbia Accident Investigation Board. They also suggested NASA find ways to limit debris, improve the ability of shuttle astronauts to inspect the vehicle's skin for damage, better understand the impact tolerance of the tiles and panels, and evaluate the international space station for use during emergencies.
Currently NASA is studying a plan in which a space-walking astronaut would apply a silicon-based caulk to damaged tiles or panels, then smooth the new surface to reduce any turbulence it might cause during re-entry.
To do this low-tech repair, there must be a way to get the astronauts in position. The shuttle's existing mechanical arm might be used, though some sort of extender would be needed to reach some places on the vehicle. NASA is working on one.
Assuming NASA's plan to finish and then disengage from the space station goes as planned, it may leave the U.S. "space partners" such as Russia and the 15-nation European Space Agency in an awkward spot.
"Europe has had a long tense history of failed deals with NASA," said Baker. "Now the president says the U.S. will pull out of the space station. Does this mean ESA will be asked to buy the space station? Will ESA have to make deals with the Chinese?"
Turning to the Chinese is "a fantasy," according to CAIB member Logsdon. "How many manned spacecraft have the Chinese launched? Just one."
Pike said NASA's new marching orders offer supporting evidence for the people around the world "who believe the U.S. too often acts unilaterally _ that we don't play well with others."