CAPE CANAVERAL, Fla. – A powerful bolt of lightning that struck a launch pad attached to space shuttle Atlantis forced NASA to delay the spaceship’s liftoff for at least one day – and possibly longer.

The launch of Atlantis and a crew of six astronauts led by Brent Jett Jr. of Fort Lauderdale, Fla., is now scheduled for no earlier than 4 p.m. Monday.

Blastoff had been scheduled for today, but managers for the National Aeronautics and Space Administration said they needed at least one extra day to inspect for damage from a powerful lightning bolt that struck Launch Pad 39B at around 2 p.m. Friday.

Atlantis is docked to that pad and was undergoing final launch preparations.

The bolt hit a lightning arrester designed to absorb the blow, but engineers saw some indications that one component on the pad and one on the shuttle might have sustained damage. They decided to conduct more inspections of the shuttle’s sensitive electronics, just in case.

“We know just enough to know that we don’t know enough to press on with a launch situation,” said LeRoy Cain, a NASA launch manager.

He said the bolt – equal to 100,000 amps of electrical current – might have been the strongest ever to strike a NASA launch pad.

Asked to describe that amount of electricity in layman’s terms, Cain said simply: “It’s a lot of current.”

He said the inspections – delayed somewhat by stormy weather that moved through the Kennedy Space Center on Saturday – could take longer than one day, and any repairs that might be needed would require more time.

NASA engineers hoped to have more clarity on the issue by midday today.

In addition, weather forecasts were growing more unfavorable by the hour, with meteorologists saying that thunderstorms were expected to pass through the Kennedy Space Center today. They said the NASA had only a 40 percent chance of launching Atlantis.

The odds improve measurably for Monday and Tuesday, with an 80 percent chance of favorable weather each of those days.

Once in space, Jett and his crew will conduct an 11-day mission to deliver and install a new power module to the International Space Station.