Discovery fuelling for launch, astronauts breakfast

++NIGHT SHOTS++ 1. Discovery shuttle on launch pad 2. Close up of base of launch platform 3. Discovery shuttle on launch pad 4. Workers in mission control 5. Discovery shuttle on launch pad 6. Weather screen in Mission control 7. Officials in mission control 8. Wide of dining room with crew of astronauts wearing matching Hawaiian shirts and having breakfast 9. Pan from left to right (on screen) astronaut Wendy Lawrence, pilot Gene Kelly, Japanese astronaut Soichi Noguchi, Space Shuttle Commander Eileen Collins, astronaut Andrew Thomas, astronauts Steve Robinson playing guitar and Charles Camarda STORYLINE: A fuel sensor system on Discovery's external tank passed initial tests early Tuesday as NASA finished fuelilng the space shuttle for the first launch attempt since the ill-fated Columbia flight two and a half years ago. NASA officials monitored the fuel sensor system on the gigantic external tank throughout the entire three-hour fuelilng process to make sure the sensors were functioning properly. A faulty reading of a sensor caused a postponement on July 13 as astronauts were boarding the spacecraft. Discovery and a crew of seven were set to blast off for the international space station at 10:39 a.m. EDT (1439GMT). The forecast improved early Tuesday to odds of good launch weather at 80 percent, compared to 60 percent the day before. During an early morning meal, crew members wore matching Hawaiian shirts. They smiled at a NASA television camera, as astronaut Steve Robinson strummed a guitar. NASA had the paperwork ready to go in case the equipment trouble reappeared and the space agency's managers decided to press ahead with the launch with just three of the four sensors working, a deviation from a rule instituted after the 1986 Challenger explosion. Only two sensors are needed to do the job. But ever since NASA's return to space in 1988, the space agency has decreed that all four have to work to proceed with launch. The fuel sensors are designed to prevent the main engines from running too long or not long enough, in case the fuel tank is leaking or some other major breakdown occurs. An engine shutdown at the wrong time could prove catastrophic, forcing the astronauts to attempt a risky emergency landing overseas, or leading to a ruptured engine. Over the past few days, NASA rewired two of the sensors to try to diagnose the trouble and repaired faulty electrical grounding aboard Discovery in hopes that would solve it. While in orbit, Discovery's crew will inspect the most vulnerable areas of the spacecraft, using a new 15-meter (50-foot), laser-tipped boom. They also will practice repairing samples of deliberately damaged thermal tile and panels. A few family members of the fallen Columbia astronauts will attend the second launch attempt. The VIP list will be topped by first lady Laura Bush and Florida Gov. Jeb Bush, her brother-in-law. You can license this story through AP Archive: http://www.aparchive.com/metadata/youtube/60170afd9fb5eedb6ad373bb13b15fa0 Find out more about AP Archive: http://www.aparchive.com/HowWeWork