Hail damage delays Atlantis launch until April: NASA

NASA said on Tuesday that it will delay the space shuttle Atlantis's launch until at least late April after a hail storm left up to 2,000dents in the vehicle's main external fuel tankand left wing.

U.S. National Aeronautics and Space Administration officials said late Tuesday that Atlantis would be moved off of its launch pad at John F. Kennedy Space Center in Cape Canaveral, Fla., and back to the vehicle assembly building for repairs.

The shuttle had been scheduled tolaunch on March 15on a mission to the International Space Station.

The thunderstorm Monday evening pelted the shuttle with golf-ball-sized hail, causing 1,000 to 2,000 divots in the giant tank's foam insulation and minor damage to about 26 heat shield tiles on the shuttle's left wing, NASA said.

"This constitutes the worst damage from hail that we have seen on external tank foam," Wayne Hale, the manager of the space shuttle program, said in a written statement.

He saida number of areas need to be repairedand thework cannot be done on the launch pad. The damage is concentrated on the upper third of the enormous external tank, a section that holds liquid oxygen propellant.

It would be at least a month before NASA could even begin considering moving the shuttle back to a launch pad, he said.

Russia also launching spaceship in April

NASA spokesman Bill Johnson said Atlantis would not launch until late April at the earliest.

The next opportunity to launch the shuttle into orbit begins near the end of April and will last about a month.

Russia also plans to send a Soyuz vehicle to the space stationin early April.

During 11 days in space, Atlantis astronauts are to deliver an almost-16,000-kilogram addition the heaviest ever to the International Space Station, along with a new pair of solar arrays.

Crew members also plan to unfurl the solar arrays, fold up an old pair and conduct at least three spacewalks.

Coincidentally, NASA managers on Tuesday began a two-day meeting at the Kennedy Space Center to determine whether there were any problems that would prevent Atlantis from launching as planned.

In 1999, hail from a storm made 650 divots in space shuttle Discovery's external tank, forcing NASA to delay a launch and return the spacecraft to the vehicle assembly building. Hail also hit the external tank ofAtlantis in 1990, causing minor damage.

The insulating foam on the external tank is of special concern to NASA since foam flew off space shuttle Columbia during liftoff in 2003 and struck the orbiter.

The damage allowed fiery gases to penetrate Columbia during re-entry, breaking up the craft and killing its seven astronauts.

NASA redesigned the external tank, removing large amounts of foam, before last year's three successful shuttle missions. The space agency plans another design change to the tank before the shuttle program ends in 2010.