(AP) -- Thunderstorms once again forced NASA to call off the launch of space shuttle Endeavour on Monday, the fifth delay for the space station construction mission.
NASA said it would try again Wednesday, after taking a one-day break.
In a scene nearly identical to Sunday, launch managers halted the countdown just minutes before Endeavour and seven astronauts were supposed to blast off in the early evening.
This time, storms packed with lightning popped up on opposite sides of the launching site, one after the other, close enough to violate NASA's safety rules.
Endeavour has been grounded for an entire month now, first by leaks, then stormy weather. If the shuttle isn't flying soon, it will have to wait until July 27 so Russia can launch supplies to the space station.
"The weather has just bitten us again," launch director Pete Nickolenko informed commander Mark Polansky and his crew aboard Endeavour. "So sorry about that."
"We understand," Polansky replied. "That's the nature of our business and like I said before, when the time is right, we'll be here, we'll be ready."
This was the third day in a row that thunderstorms prevented Endeavour from blasting off with the final piece of Japan's space station lab. Back in June, hydrogen gas leaks stalled two launch attempts.
The only technical concern Monday was a loose cover on a shuttle thruster. NASA said it would secure the cover before Wednesday's try to prevent rain from getting into the thruster.
Endeavour holds the third and final segment of Japan's enormous $1 billion space station lab, named Kibo, or Hope. It's a porch for experiments that need to be exposed to the vacuum of space. The shuttle also is loaded with large spare parts for the space station and hundreds of pounds of food for the six station residents.
When the shuttle astronauts arrive at the space station, they will make up the biggest crowd ever in a single place in orbit: 13 people.
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