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
