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SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,345

Re: Retiring the Shuttle ASAP - How do we do it?

This foam problem just gets better and better with the level of incompetance.

A couple of links first: Foam fell off area of fixes to Discovery

NASA looks at why other spots with the same type of repairs didn't shed debris.

A hazardous chunk of foam insulation that broke off space shuttle Discovery's external fuel tank during launch came from an area where workers made repairs before flight.

Prior to shipping the tank to Kennedy Space Center in March, technicians at the Michoud Assembly Facility in New Orleans sanded down part of a foam ramp to remove a fingertip-sized indentation. That area is on the same part of the ramp where a 0.9-pound chunk came loose about two minutes after liftoff on July 26.

The same location was the site of a so-called "sand and blend" repair by foam workers. During this procedure, a dye absorbed by damaged foam is poured into the blemish. The surface then is sanded down until the dye is gone.

The ramp repair can clearly be seen in "closeout" photos taken of the tank before launch as an area where the newly-exposed foam is slightly lighter in color. This type of repair is a common practice.

[url=http://www.flatoday.com/apps/pbcs.dll/article?AID=/20050806/NEWS02/508060330/1007/news02]Fuel tank processes examined

Repairs, flaws under review[/url]

NASA is investigating whether Discovery's fuel tank lost big pieces of foam in flight because of repairs made at the factory and systemic flaws in the methods and material used to build large foam ramps and ridges, according to agency documents.
Among the problems with the foam, NASA documents say, is that foam was not always applied at the correct temperature or under the correct conditions.

A 2004 document obtained by FLORIDA TODAY says the foam is being sprayed on in temperatures that are too cold. Spraying rules say the minimum temperature for foam sprayed by workers is 70 degrees, when the minimum temperature should be 80 to 85 degrees, according to the report.

The lower temperature "could result in some of the defects associated with these foams," according to the report. Resulting defects include air pockets or weakened bonds between the layers of foam, a suspected cause of the foam loss in the Columbia case.

The report also highlights flaws of the manually-applied BX-265 foam, which NASA says flew for the first time on Discovery's tank to better comply with environmental rules. The problem includes complex chemistry that makes the foam susceptible to weakening at temperatures above 200 degrees. The foam gets hotter than that as the shuttle rockets to orbit. That hot, the foam can decompose and break off.

GCNRevenger

Member

From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Retiring the Shuttle ASAP - How do we do it?

OMG... I mean, Michael Michael... is it not plainly obvious that the clowns at Michoud aren't good enough anymore? Really, somebody needs to lose their jobs over this, and get someone who doesn't give a rip about "feelings" hurt or incompetant engineers axed to go to Michoud and take over.

"systemic flaws in the methods and material used"

...means that somebody screwed up bigtime

"rules say the minimum temperature for foam sprayed by workers is 70 degrees, when the minimum temperature should be 80 to 85 degrees, according to the report"

No excuse! Somebody needs to be fired for their incompetance and as an example to others. If seven dead astronauts and a close call for seven more doesn't worry them more then their precious jobs, then somebody isn't taking their job seriously enough.

"he problem includes complex chemistry that makes the foam susceptible to weakening at temperatures above 200 degrees."

You are KIDDING me. This can't be happening... WHY IN OR ABOVE THE WORLD did these fools select this lousy foam that decomposes below operating temperature!!!

---

[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

Martian Republic

Member

From: Haltom City- Dallas/Fort Worth

Registered: 2004-06-13

Posts: 855

Re: Retiring the Shuttle ASAP - How do we do it?

For those of you that want to retire the Shuttle, here some Cartoons that you might think is funny.

http://www.cagle.com/working/050801/leahy.jpg

http://cagle.msnbc.com/working/050809/hachfeld.gif

http://www.cagle.com/working/050810/leahy.gif

Larry,

TwinBeam

Member

From: Chandler, AZ

Registered: 2004-01-14

Posts: 144

Re: Retiring the Shuttle ASAP - How do we do it?

A few ideas on the "foam" problem - sorry if they've been discussed before...

If it's the formation of ice and cryo-liquids under the foam that loosens it, while on the pad put an extra insulative "blanket" over the area that most threatens the shuttle.  The foam itself would then stay too cold to release gases, and it's own surface would stay cold enough that any humidity that's going to turn to ice will do so in the blanket or at the interface of the blanket and the foam.  Pull the blanket off just before launch.

The loosened foam must be deforming, causing cracks to open up, so air gets under the foam and blasts it up so the wind can rip it off.  If that's the case, maybe a tough, stretchy layer of paint over the surface WOULD help, by keeping air from getting down into cracks in the foam.  Again, it'd only be necessary in the area that threatens the shuttle, so it wouldn't have to be 1000 pounds of paint.  Maybe 200 pounds.  Paint might also help keep Florida's humid air out of the foam.  It sure seems simple enough to be worth a try!

If the foam could be kept flat against the tank even if air was trying to force behind it, maybe it couldn't get blasted off.  It might help if there were a mechnical means of holding the foam down - something like wide-headed rivets through the foam and attached to the tank wall.  Again - just in the critical areas above and next to the shuttle.

If the foam is being blasted outward by air getting behind it, could the airflow in the critical area next to the shuttle be altered to blast the foam back toward the ET and away from the shuttle?  Some sort of "spoilers" between the shuttle and ET?

And if we can't keep the foam from falling toward the shuttle, can we at least keep it from hitting the shuttle head on?  Add metal bumpers in front of all the leading edges of the shuttle that are at risk from falling foam.  The foam would hit the bumper and disintegrate, so its fragments flow relatively harmlessly around the shuttle.  If even a glancing blow is deadly, put a metal shield over shuttle areas considered most critically stressed during re-entry.  Eject the shields with or at the same time as the ET.