"We didn't find anything that stood out," Suffredini said. The space agency will try to limp along with the joint in its current state until repairs are made, he added.
Suffredini said that if both dilemmas persist, the space station may not be able to generate enough power to support the Japanese lab that is supposed to arrive in three sections beginning in February. There's "a fighting chance" to keep the first Japanese delivery mission on track, but beyond that, it would be "extremely difficult" to continue assembly, he said.
As for Atlantis's woes, two of the four fuel gauges at the bottom of the external tank failed during Tuesday's test, and another did not work right.
Special test equipment indicated open circuits in the connector that passes through the wall of the fuel tank, linking wiring between the gauges in the tank and Atlantis. It was too soon to know whether the shuttle would need to be returned to its hangar for repairs, Hale said.
The space agency has been struggling with sporadic fuel gauge problems for two years, ever since flights resumed following the 2003 Columbia tragedy (see story). The gauges prevent the shuttle's main engines from running on an empty tank, which could be catastrophic.
Hale said it's unclear whether the same type of connector caused the previous problems. There could be a manufacturing defect or flawed design, or the part may have been installed improperly, he noted. The connector is less than ten years old, "pretty new by shuttle standards."
"We are not going to be driven by schedule on this one," Hale said at a late afternoon news conference. "We need to get to the bottom of this, fix it and make sure it's fixed once and for all."
NASA is up against a 2010 presidential deadline for completing the space station and retiring the shuttles.
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