NASA carries out tests to assess shuttle damage

The decision on what to do is expected by Wednesday.

CAPE CANAVERAL, Fla. (AP) — NASA conducted a swift series of tests on the ground Monday to determine whether spacewalking astronauts need to fix a deep gouge in Endeavour’s belly for re-entry, and assembled a special team to weigh the three repair options.

The gouge is relatively small — 31⁄2 inches by 2 inches — but part of it penetrates through the protective thermal tiles, leaving just a thin layer of coated felt over the space shuttle’s aluminum frame to keep out the more than 2,000-degree heat of re-entry. The exposed area is 1 inch long and less than a quarter-inch wide.

Mission managers expect to decide by Wednesday whether astronauts should go out and patch the gouge. The damage is benign enough for Endeavour to fly safely home; it’s more a matter of avoiding extensive post-flight repairs to any possible structural damage, said John Shannon, chairman of the mission management team.

“This is not a catastrophic loss of orbiter case at all. This is a case where you want to do the prudent thing for the vehicle,” Shannon told reporters Monday evening.

Untested

NASA has never attempted this type of repair on an orbiting shuttle, and two of the three remedies — all developed following Columbia’s catastrophic re-entry — are untested in space.

Engineers are uncertain whether it was foam insulation that came off Endeavour’s external fuel tank and struck the shuttle at liftoff, as was the case for Columbia four years ago, or whether the debris was ice or a combination of materials, Shannon said.

Despite extensive redesigning of the shuttle fuel tank that has already cost NASA a few hundred million dollars, foam has repeatedly fallen off the tank during launch, although nothing nearly as big as the piece that crippled Columbia.

Depending on how NASA addresses the latest problem, space shuttle flights could possibly come to a temporary halt, stalling construction at the international space station once more. Foam problems have caused two lengthy hold-downs.

To patch the gouge, spacewalking astronauts would have to perch on the end of the shuttle’s 100-foot robotic arm and extension boom, be maneuvered under the spacecraft and either apply black paint, screw on a protective plate or squirt in goo.

The black coating, intended to help dissipate heat, was tested on a previous shuttle flight. The two other repair methods have been tested in vacuum chambers on Earth, but never in space.

Spacewalks

A 61⁄2-hour spacewalk by two of Endeavour’s astronauts Monday, on the other hand, was comparatively routine.

Astronauts Rich Mastracchio and Dave Williams ventured outside for the second time in three days, removing a 600-plus-pound gyroscope from the space station’s exterior that failed last October. They installed a new one in its place that was carried up aboard Endeavour. The space station has four gyroscopes to keep it steady and pointed in the right direction.

Teacher-astronaut Barbara Morgan — Christa McAuliffe’s backup for Challenger’s doomed mission in 1986 — helped monitor the spacewalk from inside the joined shuttle-station complex.

Even before Endeavour’s liftoff, NASA was planning a third spacewalk for Wednesday and a fourth for Friday to carry out more space station work. Any shuttle repairs, if ordered, would take place on one of those two outings. The shuttle isn’t due to leave the station until next Monday; landing is set for Aug. 22.

The damage occurred a minute after liftoff last week when a baseball-size piece of debris broke off a bracket on the external fuel tank, bounced off a strut farther down on the tank, then slammed into Endeavour’s belly.