NASA: Shuttle Fleet Grounded

NASA officials said Wednesday it would ground future space shuttle flights because foam debris that brought down Columbia is still a risk.

CBS News Correspondent Mark Strassman reports that new images reveal a safety threat to the shuttle program that the agency thought had been fixed.

A sizable chunk of foam insulation that came flying off the shuttle Discovery's fuel tank during Tuesday's liftoff did not hit the orbiter and does not pose a risk to the seven astronauts.

Strassman reports an image shot from the orbiter shows a large chunk of foam is indeed missing from the external tank. Debris broke off a strip of foam, called a PAL (Protuberance Air Load) ramp, which smooths the flow of air over the tank.

It is a problem NASA thought had been fixed, and represents a tremendous setback to a space program that has spent 2 1/2 years trying to rise from the ashes of Columbia.

"We won't be able to fly again" until that hazard is removed, Bill Parsons, shuttle program manager, told reporters in a briefing. "Obviously we have some more work to do."

CBS News Space Consultant Bill Harwood says the clock is ticking for the shuttle program.

"Clearly, this is going to lead to at least a crisis of confidence in some sectors. They're going to have to prove they can fix this and they're going to need to do it relatively soon," Harwood said.

NASA had said earlier Wednesday that a chipped thermal tile on space shuttle Discovery's belly did not appear to be a serious problem, based on what engineers have seen so far.

In orbit, Discovery's astronauts slowly and delicately inspected the wings and nose for launch damage, using a 100-foot movable arm with lasers and a camera mounted on its tip.

Harwood says it's going to take several days to collect and analyze images from Discovery's battery of cameras.

"In a couple days, they'll know exactly how deep that tile ding is, they'll know whether or not they need to think about repairing it or whether they can fly safely as is," he said.

NASA lead flight director Paul Hill said experts were still receiving and analyzing the data from the inspection, but during his own cursory look at the 3-D footage beamed down to Earth as the lasers panned across the spaceship's surface, "I didn't see anything that stood out."

Discovery settled into orbit Tuesday on the first shuttle flight since the Columbia disaster 2 years ago. Hours later, the space agency disclosed that an object believed to be a 1-inch piece of thermal tile appeared to have broken off from a vulnerable spot near the nose landing-gear doors on the underside of the shuttle during liftoff.

Hill said Wednesday that engineers were still studying the tile damage, but added, "Their judgment based on the data so far is that it's not going to be an issue."

He said the engineers have not yet decided whether to ask NASA to gather more data on the chipped tile by using the arm to inspect the belly.

The movable boom, operated by the astronauts via remote control from inside the spaceship, was added to the shuttle after Columbia was destroyed by damage to its thermal shield at liftoff. The inspection was planned all along, before NASA discovered the chipped tile.

Also during the liftoff, a large object, perhaps a piece of foam insulation, seemed to fly off from the big external fuel tank but did not hit the shuttle.

NASA stuck to its original work schedule and inspected only the nose and wings on Wednesday, examining the dozens of reinforced carbon panels that withstand the heat during re-entry into Earth's atmosphere. Hill said the thermal tiles on the belly could be inspected as early as Thursday if engineers request a look.

Also on Thursday, Discovery will execute a slow back flip as it approaches its destination in orbit--the international space station--so that the station's crew members can photograph the shuttle from various angles. That maneuver, too, was planned well before any launch damage was detected.

The shuttle chased after the station on Wednesday, drawing closer with every orbit of the Earth. When the astronauts awoke, the shuttle trailed the station by 5,500 miles.

Wednesday's highly sensitive inspection took several hours and employed a brand-new 50-foot extension of the shuttle's 50-foot robotic arm. The lasers can detect gouges or other damage a quarter of an inch small.

The astronauts had to be careful not to bang the equipment against the shuttle's fragile thermal shield.

Hill has said the inspections are some of the most hazardous of the new procedures put in place since the Columbia tragedy. "If we make contact with the orbiter while we're doing this, I'm looking for another job," he said in the months leading up to the 12-day mission.

Also Wednesday, astronauts Stephen Robinson and Soichi Noguchi tested tools and equipment they will use during three spacewalks. During the spacewalks, the pair will try out new repair techniques for the shuttle's tiles and delicate carbon panels; replace a gyroscope, that helps steer the space station; and install a storage platform on the station.

Two weather planes and more than 100 cameras documented Discovery's liftoff to help NASA watch for any flying debris that could threaten the shuttle. Space agency officials said they also received data from 176 sensors placed on the shuttle wings to detect any blows.

NASA officials said it was unclear if the debris spotted so far represented anything out of the ordinary. The shuttle fleet has sustained thousands of dings over the years.

Columbia was brought down by a suitcase-size piece of foam insulation that broke off the fuel tank during liftoff and struck one of the wings. The gash allowed hot gases into the wing during Columbia's return to Earth 16 days later on Feb. 1, 2003. All seven astronauts aboard died as the shuttle disintegrated over Texas.