NASA officials have decided to proceed with preparations for the launch of Space Shuttle Discovery, despite discovering a crack in the foam insulating one of the fuel tanks. The officials say they will continue to load the shuttle for a planned launch Tuesday, while inspection crews work to determine the significance of the damage.

John Shannon looks at model of external fuel tank at Kennedy Space Center, July 3, 2006

NASA's John Shannon says the triangular-shaped piece of foam that cracked off of the bracket of Discovery's fuel tank is only about eight centimeters long.

"And a lot of people that had seen the picture - it looked like a very large piece of foam, and when you got it, it looked like this small piece of bread crust, is what it looked like," he said.

He says the crack was caused by ice and condensation that built up over the past few days of bad weather, which delayed two earlier scheduled Discovery launches.

Shannon emphasized that the broken foam piece is small, and that officials have not been worried that its loss could negatively affect the flight.

Picture shows area where piece of foam insulation fell off of Discovery's external fuel tank

"So, the obvious question is, 'gee, if this were to have happened in flight, and this piece of foam were to come off, would that have been an issue?' And, the answer is 'no, absolutely, it would not have been an issue,'" he said. "It is less than half the size that we think can cause damage to the orbiter. So, although it is in an area that we don't like to have foam come off, this was not unexpected, and it would not have caused damage to the orbiter itself."

Discovery's mission is to test shuttle-inspection techniques and drop off German astronaut Thomas Reiter for a six-month stay at the International Space Station.

NASA has been concerned about cracks in the space shuttle fuel tank's foam insulation since Space Shuttle Columbia exploded over Texas on February 1, 2003. A chunk of flyaway foam had damaged Columbia's wing during liftoff, allowing superheated gas to penetrate the shuttle when it re-entered the atmosphere.