NATIONAL BRIEFING / FLORIDA

Thunderstorms forced NASA to call off the launch of shuttle Endeavour, the fourth delay for the space station construction mission.

The Cape Canaveral launch team came within minutes of sending Endeavour and seven astronauts to the International Space Station. But when storms moving in from the west violated NASA’s safety rules, managers halted the countdown. They will try again today, despite a forecast calling for more bad weather.

NASA has until Tuesday, possibly Wednesday, to launch Endeavour with the final piece of Japan’s space station lab. Otherwise, it will have to wait until the end of July because of a Russian supply ship that’s awaiting liftoff.