posted 06-12-2008 04:56 PM               

Editor's note: This thread serves to separate and centralize discussion of the damage imparted to Pad 39A at NASA's Kennedy Space Center during the launch of space shuttle Discovery on mission STS-124.

posted 06-02-2008 07:46 AM               

The source of that debris can be seen in photos of Pad 39A post-launch, as described by Bill Harwood for CBS:

Launch pad 39A at the Kennedy Space Center suffered unusual damage during the shuttle Discovery's blastoff Saturday, NASA officials said Sunday.

A photograph of the side of the pad directly behind the "flame trench" used to divert exhaust from the shuttle's solid-fuel boosters shows unidentified debris splashing into water behind the pad as Discovery climbed away. Pictures from a NASA source show buckled concrete and numerous concrete blocks or bricks, presumably from the flame trench, littering a road behind the pad.

posted 06-02-2008 10:37 AM               

quote:

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Originally posted by Mr Meek:
Is this the first time either of the pads at LC39 have suffered damage this dramatic?

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If I had to guess however, I think you are right to suggest this damage is a factor of the pad's age rather than anything specific to this launch.

Addendum: Looking back at my photographs taken of the pad during the first week of May, it appears that the buckled concrete was made worse by the launch, but was not caused by it.

posted 06-02-2008 11:48 AM               

quote:

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Originally posted by Jay Chladek:
One thought that occurred to me watching this launch was the ascent of the shuttle off the pad seemed a little slower then on some previous launches, presumeably due to the heavy payload they were flying.

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posted 06-02-2008 02:51 PM               

During the post-launch walk down of Launch Pad 39A at NASA's Kennedy Space Center, the pad team noted severe launch damage on a 100' X 20' section of the east wall of the north flame trench (seen here). Broken sections of the flame trench wall were scattered from the flame trench to the pad perimeter fence.

NASA is forming an investigation board.

The flame trench transecting the pad's mound at ground level is 490 feet long, 58 feet wide and 40 feet high. It is made of concrete and refractory brick. The top of the solid rocket booster flame deflector abuts with that of the orbiter flame deflector to form a flattened, inverted V-shaped structure beneath the mobile launcher platform's three exhaust holes.

The orbiter flame deflector is fixed and is 38 feet high, 72 feet long and 57.6 feet wide. The deflector weighs 1.3 million pounds. The solid rocket booster deflector is 42.5 feet high, 42 feet long and 57 feet wide. The structure weighs 1.1 million pounds. The deflectors are built of steel and covered with a high-temperature concrete surface with an average thickness of 5 inches.

There are two movable solid rocket booster side flame deflectors, one located on each side of the flame trench. They are 19.5 feet high, 44 feet long and 17.5 feet wide.

posted 06-02-2008 06:17 PM               

BTW, I would like to give a special shout out to the STS-124 crew and NASA for transmitting the downloaded imagery captured by the crew with full audio. I am currently watching the video they shot of the docking activities on the flight deck. Yesterday's highlights included video shot from flight day one from launch to on-orbit activities. It was a bit cute seeing the discussions between the crew when in the background you also happen to hear the fan for the shuttle's WCS spooling up as somebody on the mid-deck was getting ready to use it.

It has been really cool to watch this coverage in realtime and highlighted without the dialog being muted. This more then anything makes you feel like you are onboard the orbiter as the eighth crewmember. Frankly, I hope NASA can do more coverage like this whenever possible (some crews tend to be more private then others and of course not everything can be shown as if it were an episode of "Big Brother") as it really helps people to comprehend what is going on during a mission.

posted 06-03-2008 10:11 AM               

quote:

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Originally posted by Mr Meek:
By the way, Robert, good LON question yesterday.

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posted 06-12-2008 05:43 PM               

• NASA has high confidence that the repair can be completed with sufficient time as to not impact the targeted October 8, 2008 launch date for STS-125. "We don't have any issues relative to being able to do this work and be ready to launch the [Hubble Space Telescope] mission," said Cain.

• As Discovery launched on May 31, some 5,300 bricks on the northeast side of the flame trench were blown out, leaving bare concrete in an area roughly measuring 20 feet by 75 feet. While engineers later found signs of ricochets in the flame trench, video and still images show nothing came close to hitting the shuttle or even the underside of the mobile launch platform.

  Cain said a re-assessment of the flame trench design confirmed there is virtually no chance for debris from inside the trench to ricochet or otherwise overcome the exhaust plume to strike the orbiter. An inspection of the mobile launch platform found no debris on its upper surface nor signs of impact or damage underneath.

• Engineers discovered that the metal clips that help hold the bricks to the walls of the flame trench were severely rusted and corroded, probably due to decades of exposure to the acidic byproducts of booster exhaust. Inspectors also found areas where the absence of trowel marks indicates the epoxy intended to help hold the bricks to the underlying concrete wall was not uniformly applied. Subsequent "tap tests" have indicated voids behind 30 percent of the bricks that are still in place.

  Engineers suspect similar problems may be lurking at pad 39B. Inspections and tap tests are ongoing.

• Recommendations on the repair will be made to shuttle program manager John Shannon on June 26.

• The original brick vendor, A.P. Green, has inspected the pad, along with representatives of Atlantic Firebrick and Supply Co. Molds of the original bricks are still available but there is no existing stockpile. New bricks can be made, but not in time for the October launch.

  "We have talked to the original vendor," Cain said. "The brick contracting company and the original vendor were on site to evaluate this issue for us. There apparently are no applications similar, or necessary, today and so they don't make this kind of brick. Whether or not it could be done, I don't know if we know the answer to that yet."

• Another option under consideration, described by Cain as the leading candidate for a repair, would involve spraying the voids in the concrete with a thick coating of Fondu Fyre -- a heat-resistant Apollo-era material that is mixed with water, sprayed on and allowed to cure -- or a similar material.

  "It's fair to say one of the options is looking at spraying the areas where we've lost brick," he said. "Possibly removing more brick and spraying would be a different option, or doing something other than spraying Fondu Fyre in the areas where we've lost brick to preserve those areas."

posted 06-17-2008 01:47 PM               

I was looking at the relationship between the flame deflector, the pad and the walls and was surprised when I realized that all of the flame is deflected in teh same direction. I thought that the SRB exhaust went one way and the SSME's were vented in the opposite direction. You learn something new every day.

And to my untrained eyes, it sure looks like the wall damage appeared to be a ripple or tearing effect from underneath the right SRB.

posted 06-17-2008 02:35 PM               

quote:

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Originally posted by divemaster:
and was surprised when I realized that all of the flame is deflected in teh same direction. I thought that the SRB exhaust went one way and the SSME's were vented in the opposite direction.

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posted 06-17-2008 04:29 PM               

But, obviously, I'm fooled easily.

posted 06-26-2008 05:17 PM               

"We did find evidence of a fracture joint along a construction joint between the first and second panels of the east wall," said Perry Becker, chief of NASA's structural systems branch at the Kennedy Space Center. "We believe that fracture was brought on by a number of different components. We have found erosion of some anchor plates that were used to secure the brick to the back wall. We've found degradation of the epoxy that was used to adhere the brick to the back wall. We have found evidence of acid deposition in that area. We've found evidence of carbonation in the area, which leeches the calcium out of the concrete, which reduces the strength of the mortar-to-concrete joints."

Becker said the damage that occurred during Discovery's May 31 liftoff apparently happened when a Fondu Fyre patch over an area of earlier erosion ripped away seconds after booster ignition.

"We believe, based on pre- and post-launch pictures, that we liberated a Fondu Fyre patch that was put over an area of fairly significant erosion," he said. "We think the lack of adhesion on that wall resulted in some bowing off the back wall and resulted in the liberation of that patch. Once that patch was liberated at launch, we believe that created the intrusion point that got the hot gas behind the wall."

Once booster exhaust gases got behind the brick layer, "we had impingement on the back wall and with no real adhesive strength left in that local area, we started a localized failure," Becker said. "Due to the interlocking nature of the brick, we believe that led to a cascading failure on down the wall."

posted 06-27-2008 11:21 AM               

If These Walls Could Talk, They'd Say 'Save Me!'

The scoop: The scorched bricks beneath Launch Pad 39A at Kennedy Space Center have witnessed decades of spaceflight history. But after a recent space shuttle launch blew thousands of them from the pad, NASA intends to throw these pieces of history away.

posted 06-27-2008 06:40 PM               

quote:

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Originally posted by MrSpace86:
They should be saved and turned into launch complex fragments, similar to the ones they sell at the Air Force Station.

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It seems rather doubtful that NASA would make these bricks available to the public and risk any liability associated with distributing toxic material (even if the toxicity of the bricks is probably minor).

posted 06-28-2008 03:53 PM               

"Given NASA's precedent, I think the agency should take that additional step to find a company to embed the historic bricks safely in acrylic and make them available to museums, educational institutions, NASA employees and perhaps even the public."

Before I even read the article, this was my first thought! I only hope that NASA does take the steps to preserve the bricks, or pieces thereof, in acrylic and sell them to the public perhaps to defray the cost of fixing the trench.

posted 06-30-2008 03:11 PM               

quote:

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Originally posted by AFGAS:
The odds are that a brick owner would develop mesothelioma, and although it may take 20 to 50 years for symptoms to develop after exposure, would sue the government.

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posted 06-30-2008 06:05 PM               

quote:

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Originally posted by Hawkman:
What are the odds if the brick is encased in lucite?

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posted 07-04-2008 02:54 PM               

I have also been forwarded the following photographs documenting the progress within the trench and have been promised additional, more detailed imagery. Click on photos to enlarge.

posted 07-12-2008 11:27 AM            

NASA lit a class three bonfire under someone's ass on this one, because I have NEVER seen this many engineers tasked with the resolution of a single issue... EVER! At one point, we had 9 employees in the trench and there were 21 engineers, USA and SGS staffers in attendance.

We are now in the process of hydroblasting the surfaces with 40,000 psi filtered water. This procedure creates a very rough surface on the concrete, allowing a better purchase for the fondue fyre refractory cement. If you are watching at the Florida Today's Flame Trench blog Pad 39 cam, you will see that we have completed a significant quantity of work in these 16 short days.

posted 07-12-2008 09:08 PM               

NASA has also added new photographs of the flame trench to its KSC Media Archive.

posted 07-22-2008 11:23 PM               

Before that could happen however, anchors and plates were installed, as illustrated by the following photographs.

posted 07-22-2008 11:24 PM               

Notice the big pegs? These are nothing more than pipe segments with a plug welded to them. A hole is drilled through the top to permit a threaded rod to pass through. The wire fabric is welded to the tops of these pegs. It is difficult to see, but there is a keyway being formed into three sides of these fondu fyre panels being sprayed in place. This is to ensure that the panels have some measure of independence from one another, while at the same time affording a measure of integrated lateral support.