The loss of seven astronauts who perished when the space shuttle Columbia broke apart in the skies over a week ago is once again bringing NASA's future into question.
As it has done with past space tragedies, Congress Wednesday will begin debates about what the nation's goals for space flight are - and whether the scientific advances made by manned space shuttles are too narrow to justify the cost in both dollars and human lives.
This time around, with the nation focused on closer-to-home problems like the economy and a possible war with Iraq, the distant possibilities that space represents are a low priority for many lawmakers.
Yet even as Congress begins its inquiries, several analysts say the loss of the Columbia and its crew presents both a challenge and an opportunity for charting a fresh, more credible course for space exploration that includes a return to the moon and human missions to Mars.
During the 1990s, little was said about anything beyond the space shuttle and space station - in large part because of the station's ballooning costs. This began to leave an impression that those programs were ends in themselves, and as such, they seemed increasingly tough to justify.
But with a change in administrations, a new head at NASA, and last week's tragedy, "there's some latitude now for NASA to be a little bolder, to garner financial support for a focused program" that includes a broader human presence in space, says Ray Williamson, a professor at the George Washington University's Space Policy Institute.
Much hinges on how quickly NASA can determine the cause of Columbia's destruction and the credibility of its plan for recovering from the disaster, Dr. Williamson adds.
In addition, it's uncertain whether the current climate of sympathy for the fallen and for their families' plea that "the legacy of Columbia carry on" will translate into a sustained, increased commitment to the space program at both ends of Pennsylvania Avenue.
"The reality is that NASA is not a national priority and hasn't been for a long time," says Roger Handberg, a political scientist at the University of Central Florida in Orlando. "Decisions about NASA's budget are going to be made months from now, when the emotional shock has worn off" and lawmakers begin to weigh the money NASA gets against their favorite programs.
"It will be back to business as usual," he says.
For now, the public seems to support space exploration - with reservations. A narrow majority of Americans believe the benefits of NASA's programs justify the cost, according to preliminary results of a new Christian Science Monitor/TIPP poll. But their objectives are pragmatic, not moon-shot bold. Most respondents said they'd use extra funds to make shuttles safer or to develop new technologies for general aviation, not to work toward a manned flight to Mars.
The presence of a space station on orbit, and US ties to its international partners on the project, could come to NASA's rescue. "I don't think this administration would let the US visibly fail" by shortchanging the project or the launch systems needed to sustain it, says Dr. Handberg.
THUS, over the short to medium term, many analysts anticipate that Congress and NASA will put increasing emphasis on the orbital space plane, a mini space shuttle launched atop an expendable rocket. By 2010, NASA hopes to have the plane available as a "lifeboat" for the space-station crew. By 2012, it could help exchange crews and carry small payloads - such as experiment samples or small pieces of gear - to and from the space station. Expendable rockets would deliver heavy cargo. The White House is seeking $550 million for the project for fiscal 2004.
Beyond the medium term, the US should be positioning itself for a return to the moon and for human missions to Mars, and emphasizing the space shuttle and space stations' roles as important stepping stones along the way, according to Harrison Schmidt, an adjunct professor at the University of Wisconsin at Madison and an Apollo 17 astronaut.
"The moon is our next logical step," he says, because it is close and it has the resources - hydrogen, oxygen, and a form of helium that interests fusion-energy researchers - to yield a financial payback.
Once resource extraction on the moon is established, colonization will not be far behind, he adds. Those steps will likely trigger further exploration, because it will be less expensive to move out from orbit. The high cost of launching from Earth results from the rocket punch needed to overcome Earth's gravity.
Yet even as advocates look with hope toward manned spaceflight's future, a fundamental challenge remains. "What's still before us," Williamson says, "is developing a firm philosophical rationale for supporting human spaceflight."
To some, that rationale lies in the potential for unforeseen, but ultimately beneficial, scientific discoveries.
To others, however, the rationale is built into human nature and the current period in human history.
"We are at the incredible point in time where technology allows us to go and be in a place other than the planet we've been confined to for millions of years," says Charles Chappell, director of science and research communications at Vanderbilt University and a former NASA official. "Finding out what's over the next hill," he adds, is an integral part of human nature.