It’s the fifth attempt to launch Discovery since mid-February, when the launch of the mission had bee canceled after NASA engineers decided it was too risky to launch the shuttle because it had a malfunction at a fuel valve and the problem needed a bit more time to investigate. 

 

The fuel valve that cracked during a flight in November was analyzed more carefully. After an in depth study of the problem, NASA engineers decided that Wednesday would be a good day for a launch. The decision is not 100% permanent yet, it will be reviewed on Friday by the space agency officials. 

 

NASA engineers said they were confident that the other three fuel valves don’t have any cracks and they will work during launch. The last launch date was February 12, but NASA decided it needs more time to do things their own, safer way. 

 

"All of the other analysis, the impact testing and the fact that we've got poppets and fuel control valves that are essentially crack-free, gave everyone comfort that we could fly without a modification," Kyle Herring, a NASA spokesperson at the agency's Johnson Space Center in Houston, told SPACE.com .

 

The seven astronauts aboard Discovery will install a $297 million solar-power module outside the International Space Station (ISS). The module will enable the station to generate more power and this way increase the number of permanent residents aboard it from three to six. The Discovery crew was also trained to repair a water recycling device and other equipment on the ISS.