SUMMARY: NASA controllers grounded the shuttle fleet for at least two more months on Friday after they discovered small fuel line cracks - so far they've uncovered 11 in the four shuttles. All the cracks are very small, only a few millimetres in length, but NASA is worried that a piece of metal could chip off the fuel line and fall into a main engine during liftoff. This could have disastrous results. Two shuttle flights are currently on hold until the problem can be fixed.
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