Endeavour APU Issue Testing Under Way

Teams at NASA Kennedy Space Center’s Launch Pad 39A are testing various systems in space shuttle Endeavour to determine the cause of the heater issue associated with auxiliary power unit-1 (APU-1).

Technicians gained access to the spacecraft earlier this afternoon. They were able to confirm the cockpit control fuse panel is working.

Teams began testing thermostats associated with the heater connected to the fuel line for the APU. Initial reports indicate the thermostat side that failed during Friday’s launch countdown still is not working, as expected. Teams will continue additional testing to help determine whether the thermostat is receiving a current or whether the issue is being caused by another part of the system. Managers are not expected to decide until Sunday morning, at the earliest, whether a launch attempt on Monday is possible.

Flight Dynamics at NASA’s Johnson Space Center in Houston has refined the target launch time for Monday to 2:34:00 p.m. EDT.