NASA Finds Cracks in Shuttle Fuel Tank Foam

[drwayne]

SPACE CENTER, Houston — NASA investigators looking into what caused large pieces of foam to break free from the Columbia and Discovery have found nine small cracks in the foam of an external fuel tank. <br /><br />But program administrators are not sure whether the cracks played any role in the foam separation from the space shuttles.<br /><br />Rest of the story:<br /><br />http://www.foxnews.com/story/0,2933,176483,00.html <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[rocketman5000]

I believe it will be impossible to keep small cracks from forming. You are placing 2 dissimiliar materials in contact with each other. The expansion rates alone should cause cracks.

 

[bobw]

Space.com had a better article yesterday. It sounds like good news; if all the cracks are at the ramp it is fixable.<br /> <br />Edit: <br /><br />Which reminds me, I had a question about "A total of nine cracks – only two of them visible on the surface ." How did they find the invisible ones; dissecting the foam or using radar or something? <div class="Discussion_UserSignature"> </div>

 

[para3]

Yeah, caught that myself unless NASA officials have exray eyes or something. <br /><br />If anyone find out how NASA was able to find the invisible cracks, please post. <div class="Discussion_UserSignature"> <p><strong><font size="3" color="#99cc00">.....Shuttle me up before I get tooooooooo old and feeble.....</font></strong></p><p><strong></strong></p><p><strong><font size="4" color="#ff6600">---Happiness is winning a huge lottery--- </font></strong></p> </div>

 

[radarredux]

> <i><font color="yellow">I believe it will be impossible to keep small cracks from forming. You are placing 2 dissimiliar materials in contact with each other. The expansion rates alone should cause cracks.</font>/i><br /><br />I think this is why many consider the current shuttle system fundamentally flawed. Several years of downtime and billions of dollars have been spent, and while the risks have been reduced, the risk is still substantial.<br /><br />I suspect it will be a long time before we see a another side-mounted launch vehicle in the future.</i>

 

[dobbins]

I watched the news conference yesterday. This morning I wondered if NASA held two of them and the press was covering a different one than the one I watched. The cracks were just a minor part of what was covered but the nattering nabobs of negativism (Thanks Spiro) are going out of their way to present it in the worst light possible.<br /><br />

 

[shuttle_rtf]

>Which reminds me, I had a question about "A total of nine cracks – only two of them visible on the surface ." How did they find the invisible ones; dissecting the foam or using radar or something?<<br /><br />They brought in a process called "Shearography" after STS-107 - as one way to find such imperfections. I'm sure there's also multiple other processes which work alongside that, and I'm not positive (but will ask) if Shearography was used on the PAL ramp in this instance. They could have found them by the process of slicing the ramp into small slices, for instance.<br /><br />Also, to add to this thread, I also found it unfair that the mass media (such as the wire services) decided to go with a very small element of the update as their angle - and then use negative tones on NASA's proceedures and evaluations to get to STS-121.<br /><br />I personally thought the press conference was informative and very transparent (within the boundaries of publically released information).<br /><br />I found the overall angle to be cautious optimism - with safety and due diligence at the heart of working towards STS-121.

 

[bobw]

<font color="yellow">Yes</font><br /><br />LOL. Radar or something was supposed to be all one word <img src="/images/icons/smile.gif" /> Urgh. <div class="Discussion_UserSignature"> </div>

 

[ricklyon]

The first shuttle ET's were painted. After a few flights, in order to save, I think it was 300 pounds, wieght the paint on the tank was eliminated. I feel that they should go back to painting the tank with a tough but flexible paint that would help hold the foam together. Kind of like the hard outer shell on an M&M candy. This would reduce drag and friction on the foam surface that would tend to pull the foam off the tank. Also, if the inevitable cracks in the foam do appear, the paint would hold them together longer. The paint would bond all the foam together making it more difficult for a small piece to be pulled off the tank.

 

[drwayne]

Note that the original paint did nothing with respect to foam falling off.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[scottb50]

I still think a huge condom rolled half way down over the ET would be the easiest fix. Cut out the back to reduce weight and it might be lighter than the paint was. <div class="Discussion_UserSignature"> </div>

 

[para3]

Wow, that's a good one.<br /><br /><img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/laugh.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/laugh.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <br /><img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/laugh.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/laugh.gif" /><br /><img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <br /><img src="/images/icons/laugh.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="</safety_wrapper"></img> <div class="Discussion_UserSignature"> <p><strong><font size="3" color="#99cc00">.....Shuttle me up before I get tooooooooo old and feeble.....</font></strong></p><p><strong></strong></p><p><strong><font size="4" color="#ff6600">---Happiness is winning a huge lottery--- </font></strong></p> </div>

 

[earth_bound_misfit]

I suggested a mesh chicken wire type arangement as well, through I'm having second thoughts on it. I think at the velocity STS reaches, the mesh re-inforced foam could possibly still break away. I'm sure the NASA engineers would have looked into this idea, along with other ideas and thought better of it. <div class="Discussion_UserSignature"> <p> </p><p> </p><p>----------------------------------------------------------------- </p><p>Wanna see this site looking like the old SDC uplink?</p><p>Go here to see how: <strong>SDC Eye saver </strong>  </p> </div>

 

[para3]

I was thinking of something much finer than chicken wire where only tiny pieces of the foam would only get through. Not enough to cause problems for the shuttle. NASA can put a little less foam on to compensate for any added weight that is added by the fine mesh. There are some really lightweight and very strong fabrics as well. But NASA needs to find some way to keep the foam in place other than what they are trying.<br /><br />And if it means using someone's idea other than an engineer's, so be it as long as this works. <br /><br />The problem with most engineers-NOT ALL-is they don't have a lick of common sense. We did have 2 engineers where I worked, but one of them was let go because he was causing more problems than he was solving. And I'm surprise that the other engine is still with us. He's dumber than a box of rocks. <br /><br /> <div class="Discussion_UserSignature"> <p><strong><font size="3" color="#99cc00">.....Shuttle me up before I get tooooooooo old and feeble.....</font></strong></p><p><strong></strong></p><p><strong><font size="4" color="#ff6600">---Happiness is winning a huge lottery--- </font></strong></p> </div>

 

[nacnud]

<font color="yellow">NASA can put a little less foam on to compensate for any added weight that is added by the fine mesh.<br /><br /><font color="white">I think the thickness of foam is defined by iceing requirements, ie you can't reduce it further without creating more problems than you solve.</font></font>

 

[drwayne]

I find myself reminded of some famous sayings:<br /><br />For every complex problem, there is a solution that is simple, neat, and wrong.<br />H.L. Mencken (1880-1956)<br /><br />"For every problem there is a solution which is simple, obvious, and wrong"-Albert Einstein <br /><br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[lampblack]

I say, shrink wrap the thing to keep the foam from flying off. Industrial grade Saran Wrap would do the trick nicely.<br /> <div class="Discussion_UserSignature"> <font color="#0000ff"><strong>Just tell the truth and let the chips fall...</strong></font> </div>

 

[para3]

Well, NASA is going to have to do something about this foam, even if they have to add some kind of bonding agent. And do it quickly so they can get that big white bird a flying again before congress cut their funds. <br /><br />I'm getting a little annoyed from the lack of shuttle flights, but I want everything to be as safe as possible as well. <br /><br /> <div class="Discussion_UserSignature"> <p><strong><font size="3" color="#99cc00">.....Shuttle me up before I get tooooooooo old and feeble.....</font></strong></p><p><strong></strong></p><p><strong><font size="4" color="#ff6600">---Happiness is winning a huge lottery--- </font></strong></p> </div>

 

[drwayne]

"Industrial grade Saran Wrap would do the trick nicely."<br /><br />Holding the foam together is only one aspect of the problem. Getting a material that will do its job without itself becoming a hazard during ascent phase is another.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[scottb50]

LiveScience Staff<br /><br />LiveScience.com Mon Nov 28,11:00 AM ET<br /><br />Creating new foams like those used in beds always involves a tradeoff between strength and flexibility. But a new foam made of carbon nanotubes involves no such tradeoff.<br /><br /><br />Carbon nanotubes were first created in 1991. They're microscopic structures created by scientists who manipulate the arrangment of atoms. In a new study, the nanotubes were found to act like super-compressible springs.<br /><br />Films of carbon nanotubes were made to act like a layer of mattress springs, flexing and rebounding in response to a force, the research showed. But unlike a mattress, which can sag and lose its springiness, these nanotube foams maintain their resilience even after thousands of compression cycles.<br /><br />The product could be used for disposable coffee cups or the exterior of the space shuttle, its inventors report in the Nov. 25 issue of the journal Science.<br /><br />“Carbon nanotubes display an exceptional combination of strength, flexibility, and low density, making them attractive and interesting materials for producing strong, ultra-light foam-like structures,” said Pulickel Ajayan, an engineer and materials scientist at Rensselaer Polytechnic Institute.<br /><br />Carbon nanotubes are made from graphite-like carbon. Already their used to strenghten concrete, among other applications. The atoms are arranged like a rolled-up tube of chicken wire.<br /><br />“These nanotubes can be squeezed to less than 15 percent of their normal lengths by buckling and folding themselves like springs,” says the study's co-author Anyuan Cao, who was a postdoctoral researcher in Ajayan’s lab and is now an assistant professor at the University of Hawaii at Manoa. “After every cycle of compression, the nanotubes unfold and recover, producing a strong cushioning effect.”<br /><br />The thickness decreased slightly after several hundred compressions, but then stabalized and remained constant through 10,000 comp <div class="Discussion_UserSignature"> </div>

 

[drwayne]

Ready for delivery today!<br /><br /><img src="/images/icons/wink.gif" /><br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[henryhallam]

Obviously it's not practical to redesign the tank now, but would aerogel be strong and insulate-y enough to do the job? Certainly it wouldn't be cheap.

 

[para3]

If aerogel is what I think it is, not only wouldn't it be cheap but would add a lot of weight to the tank as well. <div class="Discussion_UserSignature"> <p><strong><font size="3" color="#99cc00">.....Shuttle me up before I get tooooooooo old and feeble.....</font></strong></p><p><strong></strong></p><p><strong><font size="4" color="#ff6600">---Happiness is winning a huge lottery--- </font></strong></p> </div>