NASA have announced that technicians and engineers are narrowing in on the likely source of what caused heaters on a fuel line for space shuttle Endeavour’s auxiliary power unit-1 (APU-1) to fail on Friday, resulting in the postponement of the Friday launch attempt for the STS-134 mission.
The NASA launch planning teams will meet Monday and are expected to determine a new “no earlier than” next launch attempt for Endeavour at that time.
Space Shuttle Program Launch Integration Manager Mike Moses said "We can tell you, pretty much, that it's not going to be any earlier than May 8 (as) there's still a whole lot of short-term work that has to be done."
Problem with power control box
Test results indicate the problem is with a power control box, the aft load control assembly-2 (ALCA-2) in Endeavour’s aft compartment. Teams are working on plans to replace the box or any faulty associated hardware. The launch team currently is backing out of launch countdown operations. There still are numerous factor to be worked out, but just based on the amount of time needed for repairs a new launch is unlikely before the end of the week, at the soonest.
Endeavour’s six astronauts are heading back to NASA’s Johnson Space Center in Houston for a few days of additional training before they return for the next launch attempt.