How

By Sidney Urquhart

Before nasa's newest shuttle Endeavour finally lifted off last week, maintenance technicians had plenty of troubleshooting to do. The $2 billion ship arrived at the Kennedy Space Center looking pretty enough, but beneath Endeavour's sleek exterior lay more than 2,000 problems, including a defective set of main engines. And wedged among the tangle of dangling wires, hydraulic pipes and contaminated water lines was one moldy Oreo cookie.