Mike Curie/STS-128 Launch Commentator: This is Shuttle Launch Control at T-3 hours and
holding. Space shuttle Discovery is poised and ready for action this evening as launch controllers
oversee their data here in Firing Room 4 at Kennedy Space Center's Launch Control Center. Discovery
performed flawlessly during its Aug. 25 launch attempt before showers and thundershowers migrated
into the Launch Pad 39 area, and refused to leave before our 1:36 a.m. launch time. And then on our
next attempt, on Tuesday afternoon while Discovery's external tank was being loaded with liquid
hydrogen and liquid oxygen, launch controllers failed to receive the proper indication that a valve had
closed in Discovery's aft compartment when they commanded it to do so. When the fill-and-drain
valve, which is an important part of the main propulsion system's liquid hydrogen plumbing, failed to
provide that proper signal, launch commit criteria required that the launch team cease filling the tank
and begin to drain it back. Subsequent analysis indicated that the problem likely was not with the valve,
or its actuator, but instead with the valve-position indicator, which is a micro-switch sensor. And a test
plan was developed to prove that analysis. Wednesday evening, launch controllers cycled the valve five
times and received the proper indications every time, and noted that the valve opened and closed
within the required time limit, and within the time that it has in its previous 15 flights. The Space
Shuttle Program mission management team met on Thursday and determined that more time was
needed to develop plans for how to resolve the issue in case we received the not-closed indication
when we attempted our launch tonight. At noon today, the mission management team again convened,
and ratified the plan that would allow us to look at alternative readings to ensure the valve closed as
expected. But as it turned out, those plans were not needed because at around 4:20 p.m., the valve was
closed and we received the proper closed indication. So, that whole issue is behind us. And that sets
the stage for tonight's launch attempt.