A star-crossed Space Shuttle Atlantis is rolling back to the Vehicle Assembly Building (VAB) at Kennedy Space Center (KSC) in Florida for repairs after a hail storm caused damage, meaning the shuttle won’t launch as scheduled March 15, NASA announced.

Liftoff now isn’t likely until late April at best, and could be even later depending on what technicians find when they inspect Atlantis in the VAB.

They will have to check some 1,000 to 2,000 divots in the Atlantis external fuel tank foam insulation and minor surface damage to about 26 heat shield tiles on the orbiter vehicle left wing, according to NASA.

It’s the second time in as many launch attempts that Atlantis has suffered from wicked weather.

Last September, after resolution of a problem with bolts fastening an antenna in place, a thunderstorm loomed overhead and a lightning bolt struck near Atlantis, forcing a check for damage of its electronics systems. Then Hurricane Ernesto rumbled in, so Atlantis was rolled back off the launch pad briefly.

This time, hail damaged foam insulation on the Atlantis external fuel tank. “This constitutes the worst damage from hail that we have seen on external tank foam,” said Wayne Hale, manager of the space shuttle program. Foam insulation is a key issue, because a piece of falling foam ultimately caused the loss of Space Shuttle Columbia and its crew of seven in 2003.

Hale said that a number of areas on Atlantis need to be repaired and are not accessible at the launch pad.

The slow shuttle journey of Atlantis back to the VAB will be followed by minute inspections, providing technicians an opportunity to take an intensive look at the external tank damage and evaluate what it will take to repair it.

“It will be about a month before we can talk about heading back to the launch posture,” Hale said, “given the repair schedule and the [International Space Station (ISS)] requirements.”

Until the damage occurred, Atlantis was to launch March 15 on a mission to the ISS.

The next launch window opens in late April and extends out to the later part of May.

The two-day Flight Readiness Review at KSC will continue in parallel with Kennedy ground operations assessment of the external tank damage.

Before each mission, the review is conducted by top-level NASA officials, space shuttle program managers, engineers and contractors approximately two weeks prior to the opening of the launch window.

They examine the readiness of the space shuttle, flight crew and payloads to determine if everything is set to proceed for launch.

The Atlantis flight crew will return to Kennedy a few days before the launch of mission STS-117 to the International Space Station.

During the 11-day (or longer) mission, the six-member crew will install a new truss segment, retract a set of solar arrays and unfold a new set on the starboard side of the station. Lessons learned from two previous missions will provide the astronauts with new techniques and tools to perform their duties.

Commanding the STS-117 crew is Rick Sturckow, a veteran of two shuttle missions (STS-88, STS-105), while Lee Archambault will be making his first flight as the shuttle’s pilot. Mission Specialists James Reilly (STS-89, STS-104) and Patrick Forrester (STS-105) will be returning to the station. Steven Swanson and John Olivas, both mission specialists, join the crew for their first flight into space.