Shuttle experts test Loads Control Assembly 2 for "root cause" of Endeavour's April 29 launch scrub. Photo Credit/NASA TV
NASA mission managers on Monday re-confirmed May 16 as the launch date for shuttle Endeavour on a delayed 16-day mission to the International Space Station with a crew of six astronauts and the $2 billion Alpha Magnetic Spectrometer
The launching from NASA’s Kennedy Space Center is targeted for 8:56 a.m., EDT The countdown will get under way on Friday.
Endeavour’s last flight was scrubbed on April 29 by failed heaters on the fuel line for the Auxiliary Power Unit-1, one of three turbines that generate hydraulic pressure for the rocket engine nozzles and the orbiter aero surfaces, components that steer the spacecraft as it climbs to orbit and descends to a landing.
“We have high confidence this problem is no longer on the ship,” said Mike Moses, NASA mission management team chairman.
“We are done with all of the troubleshooting,” added Mike Leinbach, NASA’s shuttle launch director.
Since the scrub, technicians working in the aft compartment of Endeavour on Launch Pad 39A, have replaced the Loads Control Assembly-2, an avionics box that routes electrical power to nine critical shuttle systems, and approximately 20-feet of wiring that links the box to the APU fuel line heaters.
A failure analysis revealed a short damaged circuit driver within the loads control box, though it’s not clear whether the damage was caused by the internal driver or an external source. Recent assessments revealed a power spike in a fuel line heater over temp thermostat during a June test.
Further analysis of the thermostat power spike is currently under way to determine if it may have been the “root cause.”
The ship’s recent difficulties have delayed plans to launch NASA’s final shuttle flight, a 12-day supply mission to the International Space Station with four astronauts aboard Atlantis.
The launch date has been June 28.
However, Moses said the lift off of Atlantis will slip by two weeks, or until July 12, plus or minus a week — or until sometime between July 5 and July 19.
Once Endeavour lifts off, NASA’s shuttle program managers will be prepared to settle on a more definite launch schedule for Atlantis, he said.
Endeavour’s prime payload includes the AMS, a 15,000 pound particle detector that will be mounted on the exterior of the space station to study cosmic rays, including efforts to characterize dark matter and search for evidence of primordial antimatter.
Endeavour also carries an external platform for the station that holds spare parts for communications, thermal control and robotics systems.