Endeavour launch date still uncertain

Endeavour's launch date could be pushing later next week as engineers evaluate the cause of a blown circuit inside a switch box recently removed from the orbiter.

The problem prevented some fuel line heaters from turning on last Friday, scrubbing a first launch attempt.

NASA is trying to determine if the blown fuse was caused by a problem inside or outside the box, which routes power to nine different systems.

It's now expected to take three days, rather than two, to retest electrical connections to all those systems.

Then another couple days are required to close out the orbiter's aft compartment before a three-day countdown can begin.

Endeavour's launch officially remains targeted for no earlier than Tuesday. NASA has said it will update its launch plans by Friday, if not sooner.

IMAGE: At Kennedy Space Center's launch pad 39A, space shuttle Endeavour sits poised for launch after technicians replaced the Load Control Assembly-2 (LCA-2) in its aft section. Credit: NASA/Troy Cryder