Solutions to NASA's ET problem

[dreada5]

http://edition.cnn.com/2005/TECH/space/08/12/space.shuttle.ap/index.html<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>Gerstenmaier said one short-term solution may be to remove the foam from this so-called PAL ramp area where the big piece came off, and reapply it in a better way.<br /><br />Long-term options include removing the foam altogether from this location, adding fiber to the foam to make it adhere better, or attaching some sort of netting in select spots. But with a 2010 deadline looming for the retirement of the shuttles, it's uncertain how much time and money NASA is willing to spend.<p><hr /></p></p></blockquote><br /><br /><br />What do you guys think? The netting solution doesn't sound very expensive...<br /><br />It probably is as NASA officials stated a very complex engineering problem, but I think it's going to require much more fundamental work than they have done to date, maybe in the shape of changing the type of foam, using something other than foam altogether or adding some kind of additional covering to the surface of the ET to really minimise the loss foam during ascent.

 

[mrmorris]

<font color="yellow">"The netting solution doesn't sound very expensive... "</font><br /><br />The problem isn't expense. If they found the perfect solution tomorrow, and it would cost $10 million per ET to implement, they'd do it in a heartbeat. Considering the cost of the shuttle program and the few remaining ETs where we give a rat's about the PAL ramp foam, that'd be a bargain. They'll lose more money than that in salaries very quickly. The STS program costs ~$5 billion a year -- most of it salaries and infrastructure costs. That's over $400 million every month. If a $10 million per ET fix allows them to launch a month earlier -- it's paid for itself a couple of times over.<br /><br />The <b>problem</b> to finding a solution is to determine *all* of the implications of adding it to the ET. Any change will have failure modes of its own and may affect the failure modes of other parts of the system. They have to be 100% sure that not only is the fix workable, but that it doesn't break three other things.

 

[drwayne]

"The problem to finding a solution is to determine *all* of the implications of adding it to the ET. Any change will have failure modes of its own and may affect the failure modes of other parts of the system. They have to be 100% sure that not only is the fix workable, but that it doesn't break three other things."<br /><br />BINGO! That is exactly correct, and a fact many overlook. The time to do adaquate V&V of a change is substantial.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[dreada5]

Failure Modes?!! <img src="/images/icons/smile.gif" /><br /><br />This man speaks my language! Yes, I agree - I work with FMs all day so I know what you mean.<br /><br />I'm not saying it'll be easy, but it IS possible and all it will take is TIME to agree on a good soluition and implement it. The articles I read seemed to indicate that cost was the major issue and netting doesn't sound expensive to me, relatively speaking.

 

[drwayne]

"netting doesn't sound expensive to me"<br /><br />That is the correct, but the actual physical cost of the fix is not going to be the long pole in the tent.<br /><br />Time is in fact the long pole in the tent. Time to agree on/engineer the exact methodology, time to V&V the fix. Time IS money, and a lot of it.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[mrmorris]

<font color="yellow">"The articles I read seemed to indicate that cost was the major issue..."</font><br /><br />It's certainly an issue on the front-end... especially if it's not successful. Everyone will harp on 'It took X-billion dollars to develop a fix." However, the costs of developing the solution are largely the costs spent in determining whether or not it will work. The actual fixed cost of the solution itself will quite likely be in the realm of an accounting error.

 

[mrmorris]

Type slower!!! <img src="/images/icons/smile.gif" />

 

[drwayne]

Funny, I was admiring your statement about "in the realm of an accounting error" - that was a good one.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[anotheridiot]

They just have a little 3 edged wing at the front of the cable support for turbulence at the supports for the 17" fuel line and cable brackets. Why isnt this whole area filled to eliminate all turbulence. Have a foam rectangle instead of 20 cavities to cause turbulence. <br /><br />You look at an aluminum shell, a net, a reinforcing mesh within the foam, applying the foam in the time you achieve maximum adnesion to the undercoat and they are all simplistic solutions. <br /><br />Does it need to take millions of dollars and months to implement it? I really think the nasa engineers are the smartest people in the world, but sometimes the simple solution cant be accepted without months of over engineering.<br /><br />I am proud as all hell that I live in the country that can fly the shuttle. I honestly believe the shuttle is the last current positive image of the united states. Monuments, flags, statue of liberty, all designate the last century. We are laughed at around the world, everyone hates us. But we have our shuttle and will prove we are still the greatest nation with the help of our shuttle. C'mon nasa, make us proud.

 

[rogers_buck]

Maybe they should do like we in the civilized world do when handed a pint with a lot of foam on top. We blow it off onto the table/floor to get at the beer. Put a long linear charge down the seam of the ET and set fire to it at 10K feet where the water vapor drops dramatically and the shuttle isn't going too fast. In a flash the ET will be naked.<br /><br />Ok, I'm not serious. I saw on CNN that NASA is saying they think the foam came from an after delivery repair that was made at the Cape. Was that you shuttle_guy? I guess that means they will declare victory and try again after blaming the guy who applied the patch...<br />

 

[viper101]

I disagree that Americans are hated the world over - I certainly disagree with some of the foreign policy moves - and as a Canadian I strongly disagree with those who act like America single handedly fought WW2 - Especially since Canada & co were in that war for years before the states.<br /><br />But I do agree that America has done great things in Space (and for science progress in general). A friend from Georgia once called me and asked me what made America great - and of course, the first things that came to mind were the deep space probes & the moon landings. <br /><br />Think about it - The only flag on the moon, the only flag outside of our Solar System is the Stars & Stripes. That's pretty damn impressive in my book.<br /><br />But getting on with 'hated' - I think those that honestly feel America is the great Satan (and all that crap) are those who beat the s%#t out of their wives, wield knives at every opportunity and sleep with their own family members. <br /><br />I've had a beer or two, so forgive the inchoherence of this mini-speech. America is good - maybe consumes too much resources (just like the rest of the western world) and (recently) invades countries it could have handled in other ways - and I worry about your democracy - there was something dodgy about the last election - exit polls always jive with the final results, but in Ohio, they didn't. That bothers me. But America really is the ultimate example of what humanity can accomplish if given an opportunity. For that, I applaud the US of A and wish all the Americans I've ever had the good fortune of meeting the best.<br /><br />On that note - and getting back on track - when you build a house - the insulation is the Second last layer - I think it should be the same with the bloody ET - put a shell over the damn thing and accept the reduced payload capacity. <br /><br />/Definitely not an aerospace engineer<br /><br /><br />

 

[paleo]

I'm not as up-to-date as others here on the foam issue. How is this piece of foam falling off the Shuttle different from the foam falling off the Columbia? Was that issue fixed or is this the same basic issue?<br /><br /> Wasn't the delay of 2 and a half years mostly about fixing the foam? 'If' (and maybe it isn't) it's the same issue, how would they now come up with a solution between now and the launch in September that they couldn't come up with in 2 and a half years?<br /><br /> Is 'this' foam issue unrelated to the Columbia foam issue? Or, can they make a quick fix because they understand what happened this time?

 

[drwayne]

"How is this piece of foam falling off the Shuttle different from the foam falling off the Columbia?"<br /><br />The section of foam that came off Columbia's tank came off a different area of the tank. That area was a known trouble spot. The Discovery spot was not as well known, though it may have been suspected.<br /><br />There has been some suggestion that the area that came off discovery was in an area in which the foam had been repaired. If so, this may make solving the problem easier, but it is doubtful it will be done in a short time frame.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[drwayne]

"but sometimes the simple solution cant be accepted without months of over engineering."<br /><br />There is a corallary of Murphy's law that states something like - For every problem there is an answer that is obvious - and wrong - its related to the law of unintended consequences.<br /><br />Any change that is made in the way that the foam is made/applied/held together will have to be tested at a number of levels.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>