CAPE CANAVERAL, Fla. – NASA officials decided Saturday to delay the launch of space shuttle Atlantis by 24 hours to give engineers more time to determine whether one of the most powerful lightning strikes ever at a Kennedy Space Center launch pad caused any problems.
The launch, planned for Sunday, now will not happen until at least Monday. It was the first time a lightning strike at the launch pad had caused a shuttle launch delay.
The lightning Friday did not hit the shuttle — it struck a wire attached to a tower used to protect the spacecraft from such strikes at the launch pad — but it created a lightning field around the vehicle, NASA managers said.
There was no indication that any system was damaged, but if repairs were needed they would likely take days, not weeks, said Leroy Cain, launch integration manager.
"We know just enough to know that we don't know enough to be able to press on into a launch situation," Cain said.
Engineers wanted time to pour over data on ground and flight systems. They planned to focus on an electrical system on the shuttle and an explosive used during a launch to separate the shuttle's external fuel tank from fuel-vent arm. Technicians reported a charred smell coming from that area.
"We'll open up some cable trays to make sure there's nothing burned down inside," launch director Mike Leinbach said.
The lightning strike at the launch pad was more than three times stronger than the average lightning strike and thousands of times more powerful than an electric chair, said Vladimir Rakov, co-director of the International Center for Lightning Research and Testing at the University of Florida.
Lightning has foiled space launches before.
In 1987, an unmanned Atlas Centaur rocket carrying a Navy communications satellite was destroyed after a strike just after launch. Apollo 12 was struck twice by lightning after launch, knocking out nine nonessential systems, but the flight went on as a success.
NASA managers had been concerned about storms passing through the area before launch time Sunday.
Shuttle weather officers had said earlier in the day that there was a 60 percent chance the weather would prevent the shuttle from blasting off at the scheduled launch time of 4:30 p.m. EDT Sunday.
NASA will not launch if there are storms within 23 miles of the shuttle landing runway, in case astronauts need to make an emergency landing.
The forecast was expected to improve dramatically for Monday and Tuesday, with only a 20 percent chance that weather would prevent a launch on either of those days. NASA plans had four potential launch times over five days.
Shuttle weather officers also were tracking Tropical Storm Ernesto, which was likely to enter the Gulf of Mexico on Tuesday or Wednesday and threatened to reach hurricane strength. Ernesto was not expected to affect a launch early in the week, but it could cause problems if Atlantis does not lift off until later in the week.
In a worst-case scenario, if Ernesto were to strike Texas after the shuttle's launch and workers were forced to evacuate Mission Control in Houston, the shuttle astronauts would have to leave the station and return to Earth at the first opportunity. An evacuation would mean flight controllers could not sufficiently support a mission as complex as this, which will attach an addition to the space station, NASA managers said.
In that situation, NASA controllers and the astronauts would make every effort to leave the 17 1/2-ton addition the shuttle is carrying at the space station. That $372 million addition has two solar power wings that eventually will provide a quarter of the station's electricity.
Construction of the half-built space station has been on hiatus since the 2003 Columbia disaster, which killed seven astronauts.
Atlantis' mission is the first of 15 flights scheduled to finish building the space station before the cargo-carrying shuttles are retired in 2010.