MattSparkes writes "The Shuttles March launch has been delayed to late April after golf-ball sized hail caused 7000 pits and divots in the foam that shields the fuel tank. NASA say it's the worst damage of its kind that they have ever seen, but hail is not a new problem for the agency. In 1982, a hailstorm damaged the sensitive heat shield tiles on the Columbia's wings. The damaged tiles then absorbed about 540 kilograms of rain. Once in space, the orbiter faced the Sun to allow the tiles to dry out."