NASA's Debris Analysis Team is in the final stages of reviewing launch and on-orbit photography of the shuttle Endeavour's heat shield. The ship's nose cap and wing leading edge panels have been cleared for entry as is and while 16 areas have been identified with minor tile damage, engineers have not seen anything that warrants repairs or additional inspections, a senior manager said Saturday.

Credit: NASA

Mike Moses, acting as chairman of NASA's Mission Management Team, said the DAT recommended Friday evening to forego any additional "focused" inspections of Endeavour's heat shield after examining hundreds of photos shot during Endeavour's approach to the station Friday.

"After the review they decided they did not need that additional data, which is a very good sign," Moses said. "We have not yet officially cleared the vehicle for entry, but having no focused inspection is a step down the path of saying we are going to be in really good shape.

"The reason we haven't officially cleared the vehicle for entry is, we had them focus on this focused inspection stuff first, the big things you think you might need more imagery on. But there are still a handful of minor things they need to go back and do the math, finish the analysis. ... We expect in the next day, maybe tomorrow, probably by Monday, we expect the thumbs up and to clear the vehicle for entry."

During Endeavour's approach to the space station Friday, commander Mark Polansky flew the orbiter threw a 360-degree flip maneuver, allowing the station astronauts to photograph the heat shield tiles on the ship's belly with high-resolution cameras. Sixteen areas of tile damage were noted, along with eight areas where defects were seen in spacers and thermal barriers between tiles.

Credit: NASA

Most of the tile dings were near the nose of the shuttle where foam debris from Endeavour's external tank impacted during launch Wednesday. Moses said one impact site featured a gouge 0.6 of an inch deep. The rest of the areas experienced coating damage only and none of them pose a threat to a safe re-entry.

"No real worries with any of these areas," Moses said.

Video from cameras mounted in the shuttle's twin-solid fuel boosters should be available for analysis by Sunday. Engineers are eager to examine the footage to better understand what caused an unusual amount of foam insulation to peel away from the central "intertank" area of the external tank during Endeavour's launch.

The major concern during ascent is debris that comes off in the first two minutes and 15 seconds of flight, when the shuttle is still in the dense lower atmosphere. During that period, lightweight pieces of foam can slow down so fast in the airstream that the shuttle can effectively run into them at a high enough relative velocity to cause heat shield damage.

During Endeavour's launching, most of the intertank foam that fell away was released after the period of aerodynamic vulnerability. But Moses said the mechanism is unknown and until engineers get a better understanding, they can't rule out the possibility the next tank in the sequence could shed foam earlier.

Credit: NASA

"Based on this flight, most of it came off late and so that says for this flight, that's why we didn't see a lot of damage," Moses said. "We aren't ready yet to say we're good and that we don't have a mechanism that would say it can't come off early. That's one of the big question marks we're going to have to answer as part of our flight rationale to be ready to fly the (next) tank, ET-132."

ET-132 currently is attached to a set of boosters at the Kennedy Space Center awaiting the shuttle Discovery and rollout to the pad for launch in late August. NASA originally planned to move Discovery to the Vehicle Assembly Building Monday, but the move is now on hold.

"One of the things we're going to do is go do pull tests on that tank," Moses said. "They're basically going to go cut inch-diameter size core samples and hook up a load cell to it and pull to see do we have a good bond to the metal primer underneath or not?

"We saw a fair amount of foam loss on the back side of (Endeavour's) external tank in that intertank region. You can almost see there were some areas in the crew hand-held video there's foam missing whereas in the umbilical well imagery, it's not missing. That says foam was still popping off even after (separation), which is yet another puzzling type mechanism. It's puzzling enough that foam's popping off so late without a lot of aerodynamic forces. It probably means it's thermally related, but again, we're starting to speculate."

Engineers at Lockheed Martin's Michoud Assembly Facility where the tanks are built are "looking at all that data, trying to find a common thread here that allows us to determine what that mechanism is and then based on that, do we have assurance that it can't come off earlier than that?" Moses said. "And that's really going to be the linchpin of our flight rationale."

Additional coverage for subscribers:
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VIDEO: UPDATE ON ENDEAVOUR'S HEAT SHIELD CHECKS PLAY
VIDEO: JAPANESE OUTDOOR SCIENCE PLATFORM ATTACHED PLAY
VIDEO: SHUTTLE AND STATION ARMS HANDOFF SCIENCE DECK PLAY
VIDEO: JAPAN'S EXPOSED FACILITY UNBERTHED FROM SHUTTLE PLAY
VIDEO: THERMAL COVER JETTISONED FROM THE KIBO MODULE PLAY
VIDEO: HELMET-CAMERA VIEWS AS KOPRA CLIMBS TO SHUTTLE PLAY
VIDEO: TIM KOPRA EMERGES FROM AIRLOCK FOR EVA NO. 1 PLAY
VIDEO: SATURDAY MORNING FLIGHT DIRECTOR INTERVIEW PLAY
VIDEO: OVERVIEW OF FLIGHT DAY 4 ACTIVITIES PLAY
VIDEO: STEP-BY-STEP SUMMARY OF SPACEWALK NO. 1 PLAY
VIDEO: NARRATED TOUR OF ENDEAVOUR'S PAYLOAD BAY PLAY

VIDEO: FLIGHT DAY 3 HIGHLIGHTS MOVIE PLAY
VIDEO: FRIDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: SHUTTLE CREW WELCOMED ABOARD STATION PLAY
VIDEO: ENDEAVOUR DOCKS TO THE SPACE STATION PLAY
VIDEO: ASTRONAUTS' ONBOARD CAMCORDER FOOTAGE PLAY
VIDEO: SHUTTLE FLIES OUT IN FRONT OF STATION PLAY
VIDEO: ENDEAVOUR PERFORMS 360-DEGREE BACKFLIP PLAY
VIDEO: BEAUTIFUL VIEWS OF ENDEAVOUR APPROACHING PLAY
VIDEO: STATION CAMERA CATCHES ENDEAVOUR'S "TI BURN" PLAY
VIDEO: NARRATED PREVIEW OF RENDEZVOUS AND DOCKING PLAY

VIDEO: FLIGHT DAY 2 HIGHLIGHTS MOVIE PLAY
VIDEO: TUESDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: PREVIEW ANIMATION OF HEAT SHIELD INSPECTIONS PLAY

VIDEO: FLIGHT DAY 1 HIGHLIGHTS MOVIE PLAY
VIDEO: THE FULL STS-127 LAUNCH EXPERIENCE PLAY
VIDEO: INSIDE MISSION CONTROL DURING LAUNCH PLAY
VIDEO: LAUNCH REPLAY: VAB ROOF PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PRESS SITE PLAY | HI-DEF
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VIDEO: LAUNCH REPLAY: BEACH TRACKER PLAY | HI-DEF
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VIDEO: LAUNCH REPLAY: PLAYALINDA BEACH PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PATRICK AIR FORCE BASE PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: BANANA CREEK VIP SITE PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PAD FRONT CAMERA PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: WEST TOWER PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: CAMERA 070 PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: CAMERA 071 PLAY | HI-DEF
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VIDEO: LAUNCH REPLAY: CAMERA CS-6 PLAY

VIDEO: SHUTTLE ENDEAVOUR BLASTS OFF! PLAY | HI-DEF
VIDEO: STS-127 POST-LAUNCH NEWS CONFERENCE PLAY
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VIDEO: CREW DEPARTS QUARTERS FOR LAUNCH PAD PLAY | HI-DEF
VIDEO: ASTRONAUTS DON SPACESUITS FOR LAUNCH PLAY | HI-DEF

VIDEO: WEATHER SCRUBS LAUNCH AGAIN PLAY | HI-DEF
VIDEO: CREW ARRIVES AT PAD 39A ON MONDAY PLAY | HI-DEF
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VIDEO: ASTRONAUTS SUIT UP ON MONDAY PLAY | HI-DEF

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VIDEO: FRIDAY'S PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: THURSDAY'S STATUS REPORT ON THE COUNTDOWN PLAY
VIDEO: COUNTDOWN PREVIEW AND WEATHER BRIEFING PLAY
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VIDEO: POST-SCRUB NEWS BRIEFING PLAY
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VIDEO: TIME-LAPSE OF LAUNCH PAD TOWER ROLLBACK PLAY

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VIDEO: PRE-LAUNCH INTERVIEW WITH CHRIS CASSIDY PLAY
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VIDEO: PRE-LAUNCH INTERVIEW WITH TOM MARSHBURN PLAY
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VIDEO: CREW ARRIVES JUST BEFORE MIDNIGHT PLAY | HI-DEF
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VIDEO: ASTRONAUTS SUIT UP FOR DRESS REHEARSAL PLAY | HI-DEF
VIDEO: CREW INSPECTS CARGO IN THE PAYLOAD BAY PLAY | HI-DEF
VIDEO: TRAINING SESSIONS AT LAUNCH PAD AND BUNKER PLAY | HI-DEF
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VIDEO: ENDEAVOUR IS HAULED OFF LAUNCH PAD 39B PLAY | HI-DEF
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VIDEO: SHUTTLE AND STATION PROGRAM UPDATE PLAY
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