NASA gave the green light for a launch attempt Tuesday for Space Shuttle Discovery on its Return to Flight mission (STS-114). Launch is scheduled for 10:39 a.m. EDT, and it will be carried live on NASA TV.
Senior NASA managers met Sunday at Kennedy Space Center for a launch readiness meeting. Discussions focused on recent problems related to a liquid hydrogen low-level fuel sensor inside the external fuel tank, which prompted postponement of the Shuttle’s launch on July 13. Since then, engineers have been working around-the-clock on troubleshooting the sensor system issue.
NASA ran more than 160 tests but has failed to explain what exactly caused the failure of one of the four hydrogen level sensors. The space agency hopes to detect the root of the problem during last-minute testing while the shuttle's massive external tank is being filled.
During the countdown, managers will monitor for recurrence of the problem. If any new sensor-related issues occur, engineers would stop the countdown to reassess the situation.
The sensors send data on the levels of hydrogen in the tank to determine when the three engines should be shut off during the ascent into orbit. Failure of the sensors can result in premature shutdown of the orbiter's engines during the shuttle's ascent.
Shuttle Weather Officer, 1st Lt. Mindy Chavez, reported that the development of cumulus clouds, stray showers or anvil clouds could be a concern at launch time. The chance of Kennedy weather cooperating for the launch remains at 60 percent.
Explore further: Mark Kelly, twin brother enlisted for NASA study