Space woes; NASA programs reel from shuttle problems.

Two and a half years after the catastrophic breakup of the shuttle Columbia, NASA's shuttle program roared back into space with the July 26 launch of Discovery. But faulty sensors, falling foam, and dangling insulation have raised concern for the safety of Discovery's astronauts and sparked worries for the space program's future.

After a week's delay caused by a fuel-system sensor error, Discovery embarked on a mission to the International Space Station. Shortly after takeoff, a 0.9-pound chunk of foam insulation broke off the side of the shuttle's external fuel tank but didn't appear to hit the shuttle. In February, 2003, a slightly larger block of errant foam damaged Columbia's left wing during takeoff, permitting superheated gas to permeate and destroy the craft during reentry (SN: 7/12/03, p. 21).

Since that disaster, NASA engineers have been trying to fix the faulty foam. The piece that broke away from Discovery came from a part of the tank that engineers had deemed safe and had not redesigned.

"We consider this a disappointment," says spokesperson John Ira Petty of NASA's Johnson Space Center in Houston. "Clearly, we have more work to do."

New shuttle maneuvers that enabled space station cameras to inspect Discovery didn't reveal any foam-related damage. However, the inspection did find two stray pieces of insulating cloth protruding from between thermal tiles on the shuttle's belly.

Last Wednesday, the crew conducted a successful space walk to remove the drooping insulation, gently tugging it free. However, a camera on a robotic arm documented a loose flap of thermal blanket that raised concerns for reentry.

NASA has announced that its shuttles will not fly again until engineers have identified and solved the foam-shedding problem. That decision postpones indefinitely the launch of Atlantis that had been planned for September.

"This is a big, costly delay in NASA's programs," says former astronaut Anthony England, now at the University of Michigan in Ann Arbor. He says that the problems could lead NASA to remove the aging shuttles from service before the currently scheduled 2010 retirement date.

"If they were to do that, then the investment in the space station would be at risk," England says. Without an operating shuttle fleet, several modules and other equipment needed to complete the space station will remain grounded.

Discovery's woes could also seal the fate of the Hubble Space Telescope, which requires a manned service mission by 2007, says space-policy expert Howard McCurdy of the American University in Washington, D.C. (SN: 7/24/04, p. 56). NASA had canceled any mission to Hubble following the Columbia accident, but this spring, NASA Administrator Michael Griffin revived hopes for a servicing mission.

"The administrator really wanted two successful test flights to give the 'go' signal for the Hubble servicing mission," says McCurdy. With one troubled mission and a grounded fleet, he says, "the implications for the Hubble are severe."

Pending Discovery's safe return, a second, more-successful flight could put NASA's programs back on track, McCurdy adds. "You don't stop with one unsuccessful test flight," he says. "You fix it, and you try again."