Mystery Objects Prompts Third Heat Shield Inspection for Atlantis Crew

CAPE CANAVERAL, - The six astronauts aboard the space shuttle Atlantis will conduct an unprecedented third inspection of their orbiter's heat shield before landing this week to ensure its integrity after an unidentified object appeared to shake free of the spacecraft this morning, NASA's shuttle chief said late Tuesday.

NASA space shuttle program manager Wayne Hale said Atlantis' STS-115 astronaut crew will use their orbiter's 50-foot robotic arm to scan sensitive heat shield areas Wednesday and remains on track for a planned landing at the Kennedy Space Center here Thursday at 6:21 a.m. EDT (1021 GMT).

"We still aiming for Thursday," Hale said. "We have no reason, we think, not to go take a look."

Commanded by veteran NASA spaceflyer Brent Jett, Atlantis' STS-115 crew was slated to land at the Shuttle Landing Facility here at the Kennedy Space Center (KSC) at 5:58 a.m. EDT (0958 GMT) Wednesday after an 11-day mission to resume construction of the International Space Station (ISS).

But NASA postponed the landing attempt earlier today after spotting the mystery object, which appeared to have shaken loose from the orbiter during a series of standard pre-landing flight systems and thruster checks.

"There is considerable suspicion that whatever came off the vehicle came off during the flight control systems check-out," Hale said. "We think if this piece came off...it will be easier to see. We can scan faster."

Atlantis' STS-115 astronauts have already made two detailed surveys of their orbiter's heat shield using its robotic arm and inspection boom - one just after launch and another on Monday. Both inspections turned up no signs of any damage to the spacecraft's heat shield.

Hale said the current plan is to awake Atlantis' six-astronaut crew as planned at 9:45 p.m. EDT (0145 Sept. 20 GMT) tonight and begin a five-hour survey of the orbiter's heat shield - including its underbelly - using the shuttle's Canadian-built robotic arm. Those inspections are expected to begin by about 11:45 p.m. EDT (0345 Sept. 20 GMT), he added.

Only after that inspection will shuttle engineers and mission managers decide whether to unstow Atlantis' sensor-laden inspection boom for a closer look at the orbiter's heat shield, a process that would take at least three more hours if completed on time.

"It's probably 50/50 whether we're going to bring the boom out or not," Hale said, adding that a boom inspection must end on time in order for Atlantis' crew to make their planned Thursday landing attempt for sure. "They'll make a real-time call."