NASA officials said yesterday that the agency may spend as much as $1.1 billion repairing Hurricane Katrina-related damage and aiding employees from its Gulf Coast installations at the Stennis Space Center and Michoud Assembly Facility.

"This is a preliminary estimate, for planning purposes only," William H. Gerstenmaier, NASA associate administrator for space operations, said in a telephone news conference. "It's going to be subject to a lot of update and refinement."

Gerstenmaier said NASA estimated it would spend $600 million on Stennis, located in Mississippi just over the Louisiana border, and $500 million on Michoud, about 30 miles away in New Orleans.

Both installations have been closed since the hurricane, although William W. Parsons, the space shuttle program manager in charge of relief efforts for NASA, said neither suffered extensive physical damage.

Both facilities are critical to the space shuttle: Stennis tests the main engines, and Michoud builds the external tanks. Michoud also had served as the center for an investigation into why chunks of foam broke off the shuttle Discovery's tank during launch in July.

Most of NASA's hurricane-related expenses would not be for facility repairs, Gerstenmaier said, but to support about 180 Stennis employees and an unknown number of Michoud workers whose homes were wiped out.

-- Guy Gugliotta