Space Shuttle Flight Delayed by Freak Thunderstorm

Feb. 27, 2007 — -- The next flight of Space Shuttle Atlantis, its giant orange external tank damaged in a freak hailstorm, will be delayed at least a month, said NASA.

The damage to the tank's delicate foam was enough --and hard enough to reach -- that engineers will have to haul the shuttle off the launch pad for repairs.

The foam insulation on the tank was pitted in hundreds of places, said engineers. New foam can be sprayed on and allowed to harden, but the work will have to be done in the Vehicle Assembly Building, the massive hangar where shuttles are serviced. The gantry at Launch Pad 39A does not allow sufficient access to the nose of the tank.

The work will take several weeks, said NASA, assuming there is no more damage than what crews have observed so far.

"The bottom line," said Wayne Hale, the space shuttle program manager, "is that we do not believe we can make the March window for the launch of Atlantis."

The flight, designated STS-117, is a visit to the International Space Station to deliver new components. A dozen such flights remain before the shuttle fleet is scheduled to be retired in 2010.

At the earliest, said Hale, STS-117 would now begin in late April. Even if the foam repairs take only a couple of weeks, NASA would have to wait for a visit to the ISS by a Russian Soyuz spacecraft, which is scheduled for the middle of the month.

The damage was concentrated in the upper third of the 153-foot-tall external tank, a section that holds liquid oxygen propellant.

Monday evening's thunderstorms moved quickly and had winds of up to 60 miles per hour. The size of the hail was between a half inch and two inches, and landed only at the NASA space center. The National Weather Service considers three-quarters-of-an-inch-size hail to be "severe," said David Sharp, a meteorologist with the weather service.

"Most people didn't see thunderstorms, let alone severe thunderstorms," Sharp said. "It only occurred in one location, and that was NASA's Kennedy Space Center complex."

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. In 1995, Space Shuttle Discovery was sent back to the Vehicle Assembly Building because of fuel-tank damage caused by a pair of woodpeckers that drilled about 200 holes in the rust-colored foam insulation, apparently in an attempt to roost and build nests.