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Discovery's Dangling Gapfiller Removed by Hand
Cyclotron_Boy writes "According to the New Scientist and NASA TV, Discovery's gap-fillers were removed successfully by hand by astronaut Steve Robinson earlier today during the eva. They didn't even have to use the forceps or the makeshift hacksaw-blade tool."
...Good news everyone! You get to live!
adventure-today.com
Transcript of conversation between Discovery and ground control:
Discovery: OK, Houston...I'm in position..I see the dangling gap-filler now.
Houston: OK, Discovery...just grasp the gap-filler and pull.
Discovery: OK, Houston...I'm pulling now...it's coming out...it's coming out rather easily.
Houston: Just keep pulling gently and firmly...you're doing well.
Discovery: It's still coming, Houston...there's a lot more here than I thought...
Houston: Say again, Discovery?
Discovery: I said there's quite a lot of gap-filler here...about twenty yards so far...
Houston: STOP PULLING, Discovery...it seems you're unravelling the whole belly of the ship!
Discovery: I'm what, Houston? Say again, ple...OH SHIT! THE GODDAMNED TILES ARE ALL FALLING OFF!
Houston: Don't panic, Discovery.
Discovery: DON'T PANIC, YOU ASSHOLE? WHAT SHOULD I DO? WE NEED THOSE TILES!
Houston: Stand by, Discovery...we're working on a solution.
Discovery: SCREW YOU, HOUSTON! We're going to the ISS now...send up another shuttle to carry our asses back home!
Houston: Um...yeah...about the other shuttles, Discovery...
Discovery: What NOW?
Houston: Yeah...the shuttle fleet has been permanently grounded...too many people freaked about the foam thing...
Discovery:Nobody up here CARES, Houston...you get us a flight outta here NOW, or we start smashing satellites!
Houston: OK, OK, Discovery...no need to get violent...I'll make some calls.
Discovery: Yeah...you do that...and just so you know we're serious...
Houston: What do you mean?
Discovery: When we hear some good news from you, you'll get CNN back. Not before.
____
~ |rip/\/\aster /\/\onkey
The idea was that this dangling material might focus heat onto those surrounding tiles like a blowtorch on re-entry. Intead of the heat being evenly distributed over the entire surface, that area might get super-hot and burn up the shuttle.
The fabric is to prevent the tiles from banging together on lift-off. From the gist of the article, it sounds like it doesn't matter for re-entry. I guess they'll find out the exciting way when they try to land.
/. ++
"What's Bond doing?"
"I think he's attempting reentry, sir."
According to the article they are made of ceramic-coated fabric and serve as buffers so the tiles do not rattle together and get damaged. I would imagine that during liftoff the ride is a little bumpy. The article also says that the only reason they are doing this is they think that they may cause added heat due to friction during re-entry.
If your read the article to the end, you'll notice the passage that they put some material samples in a bag to see how they fare in open space environment. Well, let this to be told: one of these samples was a LIVE MOUSE !
... that's one very expensive mousetrap.
Hmmm
On a more serious note, I imagine they're running this experiment to prepare for the eventual necessity of resusitating a human after exposure to vacuum. We use animals in medical experiments, to test new food additives, and even to make sure our beauty products are safe for people.
So, unless you want to give up medical research, beauty products, and dozens of other things that we take for granted--and need to ascertain are safe before they come to market--get over it. They aren't tortuing animals for the thrill of it, they're doing important science designed to save human lives, and regardless of what propoganda may be coming out of the mouths of PETA zealots, human life is more valuable than animal life. That's why we eat the critters and wear their skins, after all (or have you never owned a pair of leather shoes?).
The Future of Human Evolution: Autonomy
Since the tiles thermally expand or contract very little compared to the orbiter structure, it is necessary to leave gaps of 25 to 65 mils between them to prevent tile-to-tile contact. Nomex felt material insulation is required in the bottom of the gap between tiles. It is referred to as a filler bar.
Normal debris and dust would certainly burn up, but this is a material that is specifically designed not to burn up on re-entry. AFAIU, the reason they want to get rid of it is that it might cause an increase in temperature because of the additional friction.
Reality is defined by the maddest person in the room
I'm just finishing reading "Comm Check," a book on the Columbia accident by Michael Cabbage and William Harwood. I've read a lot about the shuttle ever since its first flight 24 years ago, and if there's one thing that's abundantly clear, it is this: the shuttle is a lemon.
What's so tragically funny here is that, in the book, a NASA rep is quoted as saying "the shuttle isn't a lemon" right after the CAIB report pretty much said NASA was flying a platform that was not only unreasonable unsafe, but also one having such serious design flaws as to be much less safe than necessary. Spaceflight may never be as safe as an airplane ride, but the level of risk associated with the shuttle is just much more than it could've been with a better design.
Disocover magazine had a lengthy article about twenty years ago on how the shuttle was developed, and it was an amazing insight into how so many compromises can add up to a vehicle that is not only hugely different than what was originally invented, but also one that just doesn't do anything really well. The cargo capacity was too small. It can't achieve high orbits. It lands as an unpowered glider with a glide ratio of a brick wall. It has solid boosters that can't be throttled, trimmed, or turned off. There is no practical escape or abort manuver during the most dangerous parts of the flight (launch & re-entry). Worst of all, it's designed in such a fashion that there are an amazing number of "criticality-1" items. If a crit-1 item fails, it will result in "loss of mission, crew, and vehicle." The shuttle system has several thousand crit-1 items. To the average I.T. geek, that's like running a few thousand servers, each holding billions of dollars worth of data, and not having any redundant hard drives, power supplies, or UPS's. In other words, madness.
There isn't a single solitary thing the shuttle does better than the Apollo-era capsules it was supposed to replace. Launch costs for the shuttle were supposed to be 1/10th those of the throwaway boosters, but instead they are more than ten times what the Saturn V cost in adjusted dollars.
So, to sum it up, the shuttle is more expensive, less reliable, less capable, and more dangerous than its predecessor. Yeah, gimme more of that.
The ISS is also a boondoggle for many of the same reasons. Why do we have a shuttle fleet? To build the space station, of course! Why are we building a space station? To give the shuttles somewhere to go, of course! It's a circular argument. No shuttle equals no station, and no station equals no shuttle. No wonder NASA has its head so far up its exhaust nozzles it can't see the shuttle is an amazing failure. To admit failure would be to kill off the two biggest projects the organization has.
As has been said elsewhere here, our technology is just not yet at the point where something like the shuttle is practical. We just don't have the propulsion and materials to do it just yet. What we should be doing instead is using the best practical technologies out there, namely BDB's (Big Dumb Boosters). The aren't sexy, but they work, and they can haul a cubic buttload of cargo into orbit -- or beyond.
Unfortunately, I have the sinking feeling NASA is going to have to kill another seven astronauts before they finally, regrettably put the shuttle to bed. It was a good try, but you have to be able to admit when you are wrong. Build us a modern version of the Saturn V. With modern materials and modern computers, it could be made more cheaply and even more reliable than before, probably with more lift capacity as well. Make it so it does one thing very well. We don't need a Swiss Army knife of a shuttle to get into space, not when you've got much better proven technologies that are already available. NASA can get this right. The big question is, will they?
In the end they will lay their freedom at our feet and say to us, Make us your slaves, but feed us. - Fyodor Dostoyevsky
Rather than using tiles wouldn't it be better to use some sort of spray adhesive
The tiles are heat radiators, not adhesives. Perhaps you meant the filler? It's not an adhesive either. There has to be gaps between the tiles (because the skin and tiles don't have the same thermal expansion coefficient), but gaps can pose problems (they increase the likelyhood of tiles falling out, for one; they also tend to channel in extra heat during reentry). The fillers deal with both of these issues.
What actually attaches the tiles to the skin isn't the filler, or even an adhesive - it is a felt strain isolation pad. A simple adhesive would come loose under thermal expansion. The tiles are attached to the pad, which is in turn attached to the skin.
"It felt almost as good as stealing cars from grandma." -- Margaret Thatcher, probably.
Are you serious? How would it have looked if they had left the gap filler in place, and then they lost the shuttle? Especially since they came out and said that they didn't understand the phenomenon well enough to guarantee that it was fine. The reasoning of "it didn't hurt us last time, so we can get away with it forever, even though we don't understand what is happening" contributed hugely to both the Columbia and Challenger accidents.
... but by then it's too late.
It's like saying: sometimes when I walk briskly, I get a crushing pain in my chest and numbness in my arm. I don't understand why it is happening, but it goes away in a few minutes, so I must be perfectly fine. -- It only takes one "major problem" to disprove the assertion that there is nothing wrong
Toronto-area transit rider? Rate your ride.
The gap filler is needed to keep the tiles from rattling on LIFTOFF. Once in space, we don't need it.
WE? What, are you posting from orbit?
Stop by my site where I write about ERP systems & more
The Russians have the much cheaper and safer soyuz, not because they are especially smarter, but because they just cannot afford to run their shuttle.
The Russians understand something that NASA does not, namely that their technology is limited and thus must be overengineered for saftey. Everything about the former Soviet space program was overdesigned for a reason, just like our Saturn V was: to give good safety margins without going gonzo with costs. If you've got four engines making enough thrust to get you into orbit, you add a fifth for safety and then run all your engines at 80% rated thrust for even more safety. Is it efficient? No, but it's safer.
Now, I'm not about to argue that space exploration is, or ever should be, perfectly safe. That is obviously absurd. However, the more of a design margin you have, the less meticulous you have to be when preparing to launch the vehicle. Almost all the cost overruns in the shuttle program are due to the incredible number of inspections and maintenance needed to turn a shuttle around. With a throwaway booster, you don't have any of that. Sure, you're junking valuable hardware every time you launch with a throwaway booster, but it actually costs less to do it that way. Why do you think commercial satellites are launched on Delta rockets instead of the shuttle?
Take a modern top-fuel dragster as an example. It is designed to do one thing: go as fast as you can in one quarter of a mile. Everything inside the engine is designed to last roughly just that distance, and it is torn down and rebuilt pretty much completely between every run. It is, in essence, a throwaway booster. Dragster teams do it this way because it is impractical to build an engine that can survive multiple runs and be competitive. Sure, it's expensive. But losing the race is even more expensive.
NASA needs to get away from giving us a Ferrari of a shuttle, with all its myriad valves, camshafts, and amazingly expensive maintenance, and instead give us a slightly-updated version of the 60's-era Chevy Big Block. Sure, a Ferrari can get 400hp out of a 2.5-liter engine, but it must use exotic techniques to do so. A big block V8 can make 400hp all day long without working hard, and it costs pretty much an order of magnitude less to construct and maintain. We need the Chevy, not the Ferrari, if we're going to get back into space on a large scale.
In the end they will lay their freedom at our feet and say to us, Make us your slaves, but feed us. - Fyodor Dostoyevsky
Okay, I misunderstood the "Everything was going good for 20 years" comment. In the context of just the TPS, there have been no major disasters in the history of the STS prior to the final flight of Columbia. I was thinking of the STS as a whole. My bad.
That said, I still stand by the rest of my comment. The fact that it problems never resulted in a disaster prior to 2003 does not mean that there were never any serious problems. I see this attitude all the time and it's wrong. People get away with doing stupid things for a while -- years, sometimes. Then, for whatever reason, they stop getting away with it and come to me and say, "Fix it", and won't listen when I point out that it is their behavior that is the problem.
"We've always done it that way" makes a lousy epitaph.
dragonhawk@iname.microsoft.com
I do not like Microsoft. Remove them from my email address.
The SR-71 can maintain Mach 3 (the aircraft can fly Mach 3.3 what limitations in the handbook has yet to be declassified) while the Mig-25 can only fly at 2.83 for limited amounts of time. The SR-71 has a range of 2,900 miles unrefueled, while the Mig-25 has 537 miles in the same conditions. The SR-71 routinely flew at 80,000ft, while the Mig-25 had a maximum service altitude of just over 67,000ft.
How much the Mig-25 actually cost to develop and produce is unknown, just going by the cost per an aircraft is not a accurate measure because the Russian Air Force already ate the cost of the aircraft development, while when you talk about cost per an aircraft in US circles, we talk about total cost of the project divided by the number of aircraft produced. Which is why many aircraft top a billion per an aircraft.