BEIJING, June 21 (Xinhuanet) -- NASA managers Wednesday were in the process of evaluating Atlantis' heat shield, gap filler protruding from a wing and the status of a repaired thermal blanket before the space shuttle touches down Thursday in Florida.

    The shuttle's first landing opportunity at 1:55 p.m., EDT, on Thursday, had thunderstorms predicted to be within 34 miles of the landing strip at Kennedy Space Center and clouds within 8,000 feet, both violations of flight rules.

    Engineers had initially made a mistake about how hot the thermal blanket could get during re-entry and wanted to recheck the data, plus determine the gap filler's ability to withstand the heat and aerodynamics of re-entry, said mission management team chairman John Shannon.

    "The engineering and safety teams believe there is no risk at all during re-entry," Shannon said.

    Atlantis commander Rick Sturckow told Mission Control in Houston the weather looked fine to him as the shuttle flew 214 miles above the state.

    Atlantis has seven opportunities to land over four days.

    Mission Control said landing opportunities at Kennedy, the primary landing site, look slightly better on Friday and Saturday. A backup landing site in California would be considered on Friday. That backup site plus another in New Mexico would be activated Saturday if necessary.

    Atlantis has enough power for its systems to orbit until Sunday, but managers want the shuttle to land by Saturday. The flight would only be extended to Sunday if there were technical problems that needed to be fixed.

    (Agencies)