person
crews rotate every six months using Russian Soyuz rockets.
The rockets don't have near the capacity of the shuttle,
which is needed to complete construction of the station.
NASA officials, meanwhile, said they were looking into
whether a small crack in the foam on Discovery's fuel tank
may have caused a 1-pound (0.45-kilogram) section of
insulation to break off during its climb to orbit. The
piece of foam, which was reminiscent of the one that doomed
Columbia, did not hit Discovery.
However, the large piece of foam did cause the space
agency to suspend future flights until it can prevent
shedding of similar pieces from the external tanks, which
are used to fuel shuttle launches.
The agency also is considering whether there could have
been a mistake in the foam's application, whether the foam
was defective or was handled by too many people, or if the
tank had been damaged during its shipment to Florida from
the Louisiana plant where it was manufactured.
NASA has already spent $1.4 billion and 2 1/2 years
working on the problem.
So far, space agency officials say Discovery's mission has
been a success.
The crew completed its goals: the resupply of the space
station, bringing home the station's trash and intense
inspections of Discovery for damage. The astronauts also
tested repair techniques on orbit that were developed after
Columbia.
«The glaring difference now from (Columbia) is we do have
these tools that will tell us what is going on the outside
of the vehicle and the bottom of the vehicle in places that
we didn't have the capability of seeing before,» flight
director Paul Hill said. «And we have analytical tools
available to us now to assess damage, if we detect it, that
weren't available to us before the accident.»
While in orbit, spacewalking astronaut Stephen Robinson
successfully completed unprecedented repairs to Discovery's
belly when he removed two protruding strips of tile filler
that engineers thought could lead to dangerous overheating
during the trip home.
Engineers feared leaving the strips could cause a repeat
of Columbia's disastrous re-entry in 2003 when the
spacecraft broke apart over Texas as it headed to Florida.
--mor
1328 Local Time
1028 GMT