The launch of space shuttle Endeavour, originally planned for last Friday, will be delayed at least until following the discovery of problems with a heater on a fuel line.
NASA says the failure appears to be a power problem within the aft load control assembly-2 (ALCA-2), a box of switches controlling power feeds. The heaters prevent the fuel from freezing while the shuttle is in space.
"That basically means the power is not getting out to the heaters that weren't working on launch day," said space shuttle program launch integration manager Mike Moses.
Engineers plan to remove and replace the box - but it's not a simple process. Once the new box is installed, it needs to be checked out over a two-day period, and the team will also need to examine the failed box to establish precisely what went wrong.
"We can tell you, pretty much, that it's not going to be any earlier than [May 8]," Moses said. "We're really not even setting the schedules today. There's still a whole lot of short-term work that has to be done."
Endeavour's six astronauts don't get to rest either - they're heading back to NASA's Johnson Space Center in Houston for a few days of additional training. Launch countdown operations have been suspended.
"Responding to problems is one of the things we do best around here, and the team always likes a good challenge," said shuttle launch director Mike Leinbach. "I'm sure we're going to be really glad when Endeavour's finally on orbit, but right now, the team is upbeat and ready to execute."
A new target launch date is likely to be set today.