News

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

A sizable chunk of foam insulation flew off the shuttle Discovery's fuel tank during liftoff Tuesday, NASA officials said. They do not believe it hit the orbiter, posing a threat to the seven astronauts when they return to Earth. But they plan a closer inspection of the shuttle to be sure.

The loss of a chunk of debris, a vexing problem NASA thought had been fixed, represents a tremendous setback to a space program that has spent 2½ years and more than $1-billion (U.S.) trying to make the 20-year-old shuttles safe to fly.

“We won't be able to fly again” until the hazard is removed, Bill Parsons, shuttle program manager, said in a briefing Wednesday evening.

“Obviously, we have some more work to do.”

NASA has said all along Discovery's mission was a test flight designed to check the safety of future shuttle missions. Mr. Parsons refused to give up on the spacecraft that was designed in the 1970s.

“We think we can make this vehicle safe for the next flight,” he said, declining to assess the long-term impact on the manned space program.

“We will determine if it's safe to fly.”

In orbit, earlier, Discovery's astronauts slowly and delicately inspected the wings and nose for launch damage, using a Canadian-built 15-metre extension to the robotic Canadarm with lasers and a camera mounted on its tip.

NASA diclosed an object believed to be a four-centimetre 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.

Engineers have not yet decided whether to ask NASA to gather more data on the 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 15-metre orbiter boom sensor was built by MDA Ltd. in Brampton, Ont., the company that developed the shuttle's Canadarm and a second robotic arm on the International Space Station.

The inspection was planned all along, even before NASA discovered the chipped tile.

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

On Thursday, Discovery will execute a slow backflip as it approaches its destination in orbit — the International Space Station — so the station's crew members can photograph the shuttle from various angles. That manoeuvre, too, was planned well before any launch damage was detected.

The shuttle chased after the station Wednesday, drawing closer with every orbit of the Earth. When the astronauts awoke, the shuttle trailed the station by 8,850 kilometres.

During Wednesday's highly sensitive inspection, the astronauts had to be careful not to bang the orbital boom sensor against the shuttle's fragile thermal shield. The inspections are some of the most hazardous of the new procedures put in place since the Columbia tragedy.

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, which 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.

Experts were analyzing the sensor data and studying the photographic images frame by frame.

“There is no question that we have more data now than we have ever had before,” flight director LeRoy Cain said.

“We are going to see things when we look and so one of the things we have worked really hard on is to make sure we understand what are we looking at.”

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.