What’s the main idea of the news item? [originaltext] (27)Liftoff of the spac

(27)Liftoff of the space shuttle Discovery has been delayed until July at the earliest. A launch was originally planned in May.(28)NASA scientists are concerned about the possibility of ice chunks falling off the shuttle’s fuel tank. Such an incident could cause the same kind of catastrophe that led to the demise of the space shuttle Columbia and its crew more than two years ago, as the shuttle was reentering the earth’s atmosphere. Engineers are working on making a necessary adjustment to eliminate the danger.