Three of four sensors standard kept

At Friday's space shuttle program Flight Readiness Review, NASA managers confirmed launch criteria of three of four sensors working, so long as the single failure is of a known type.

Since 2005, sensors have suffered from intermittent signals. An intermittent signal would be considered a known failure. High voltage, for example, would be considered unknown or new.

Moving the launch date up a day to Feb. 6 was discussed but rejected.

"We might have been able to go a day earlier, but it was academic since the (International Space Station) wouldn't have been ready for us," NASA spokesman George Diller said.

A newly installed feed-through connector was discussed at length, said Diller.

"The connector we've got in there is first-flight hardware," he added.

The outside leads of the connector have been soldered in hopes of preventing the intermittent signals from low-fuel sensors that scrubbed launch attempts on Dec. 6 and 9.

Engineers discussed what different readings might come from the reconfigured connector.

"They want to be sure they're all in agreement when we start tanking about about how we would proceed, particularly if it get something we don't expect to see," said Diller.

Also discussed was a program to replace RCC panels on the orbiters' wing leading edges. Using a new technique, engineers have detected possible flaws in some panels. NASA has devised a new standard, which will trigger replacement of the heat resistant panels.

All Atlantis' panels meet the standard, said Diller.

IMAGE NOTE: Click to enlarge the NASA image of Lockheed Martin technician Lloyd Johns working on a replacement feed-through connector in shuttle Atlantis' engine cutoff sensor system. Faulty circuits within a feed-through connector forced NASA to scrub two attempts to launch Atlantis in December. Its mission now is slated to blast off on Feb. 7. Photo credit: NASA/George Shelton.