Post by thread:[ot]: shuttle damage

it looks like the request for satelite imagery, to inspect the left wing, was turned down a mistake in hindsight it seems to me that a visual inspection of the exterior of the shuttle would be a good idea, similar to the standard practice of the walk around inspection that every pilot does before flying an airplane especially more so, because of the unforgiving nature of the re-entry environment! Why is an EVA is so problematic? I don't see why they couldn't schedule one for training, we need this skill. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

At 2:13 PM -0600 3/13/03, rad0 wrote: ... >Why is an EVA is so problematic? > > I don't see why they couldn't schedule one for training, we need this >skill. What I heard...somewhere...is that the belly side of the shuttle is very smooth (duh!) and so there aren't places to grab or hold on to. One expert said the probability that deadly damage would be caused by an EVA is much higher than the probability of discovering deadly damage due to some other cause. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

----- Original Message ----- From: "Philip Galanter" <spam_OUTlistTakeThisOuTPHILIPGALANTER.COM> To: <.....PICLISTKILLspam@spam@MITVMA.MIT.EDU> Sent: Thursday, March 13, 2003 2:41 PM Subject: Re: [ot]: shuttle damage {Quote hidden}> At 2:13 PM -0600 3/13/03, rad0 wrote: > ... > > >Why is an EVA is so problematic? > > > > I don't see why they couldn't schedule one for training, we need this > >skill. > > > What I heard...somewhere...is that the belly side of the shuttle is > very smooth (duh!) and so there aren't places to grab or hold on to. > One expert said the probability that deadly damage would be caused by > an EVA is much higher than the probability of discovering deadly > damage due to some other cause. > I've heard this also, but I don't understand it. Don't they have jet packs that you could use to get under there and examine it? You don't have to touch it do you? -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

rad0 wrote: >it looks like the request for satelite imagery, to inspect the left wing, >was turned down > > They requested one, which was in process. The engineers then assured the decision makers that no relevant damage was even possible with the foam, therefore the decision was made to cancel it in the interest of time and money on the air force's part. >Why is an EVA is so problematic? > > They didn't have the EVA equipment on board (for space/weight savings), they didn't have the shuttle arm on board (same reason), they have space suits, but there are no places to get a good view of the affected areas without losing hold of the ship. It's possible, I suppose, to attach rope to oneself and float free in the direction of the view you want, but there still exists huge dangers of ramming into the shuttle and causing damage to oneself and/or the ship. It may not have been considered, or was discarded as too risky. Besides, the ground photos would have been safer, cheaper, quicker, etc, and they were still too 'expensive' somehow to be used based on the evaluation of the engineers. This was a tragedy, but there was no one big failure on any person's part. It was a series of tiny errors and miscalculations which ended up in disaster. If they had the photos or the EVA, they may have shown so little visible damage that they might have decided to land anyway. If the damage was visible they would still have had to decide whether it was enough damage to not risk a re-entry based on the only other option being sending another shuttle up (risky) and repairing it (probably not reasonable given the time frame) or off-loading the passengers and bringing them back down (again, time would be an issue since new seating would have to be constructed without lengthy testing, R&D, etc). -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

----- Original Message ----- From: "M. Adam Davis" wrote: > > >it looks like the request for satelite imagery, to inspect the left wing, > >was turned down > > > > > They requested one, which was in process. The engineers then assured > the decision makers that no relevant damage was even possible with the > foam, therefore the decision was made to cancel it in the interest of > time and money on the air force's part. > > >Why is an EVA is so problematic? > > This surpises me, in hindsight of course. I've heard that what they call foam is more like concrete. {Quote hidden}> > > They didn't have the EVA equipment on board (for space/weight savings), > they didn't have the shuttle arm on board (same reason), they have space > suits, but there are no places to get a good view of the affected areas > without losing hold of the ship. > > It's possible, I suppose, to attach rope to oneself and float free in > the direction of the view you want, but there still exists huge dangers > of ramming into the shuttle and causing damage to oneself and/or the > ship. It may not have been considered, or was discarded as too risky. > > Besides, the ground photos would have been safer, cheaper, quicker, etc, > and they were still too 'expensive' somehow to be used based on the > evaluation of the engineers. > > This was a tragedy, but there was no one big failure on any person's > part. It was a series of tiny errors and miscalculations which ended up > in disaster. If they had the photos or the EVA, they may have shown so > little visible damage that they might have decided to land anyway. If > the damage was visible they would still have had to decide whether it > was enough damage to not risk a re-entry based on the only other option > being sending another shuttle up (risky) and repairing it (probably not > reasonable given the time frame) or off-loading the passengers and > bringing them back down (again, time would be an issue since new seating > would have to be constructed without lengthy testing, R&D, etc). > I thought the jet packs were on board as part of the standard equipment, I didn't consider this. And my 'walk around' idea may not really be worth it. The damage may well have been hidden. But with visible damage, found. They could have parked in orbit, sent up a shuttle with a crew of just two, with everything needed to recover the crew either to earth or to the space station. And then remotely recovered comlumbia. It can do this, can't it? -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

I was wondering why they do not have a remote controlled gizmo eject and fly around the ship to inspect for damage. It could be small and light enough and only capable of slow speed (restricted nitrogen jets) so it would not be able to cause damage even if it would contact the ship. It could be tested before being allowed to go to the sensitive part of the ship. I think that a device roughly bathroom sponge sized with a small color camera (maybe stereo camera) and nitrogen jets would be possible. It could be untethered and commanded to lose itself by expelling the remaining nitrogen when finished with inspections, in a safe direction. Since it would only have to work for maximum 20-30 minutes, thermal management, batteries etc would not be so hard to manage. Maybe it would have a small amount of water that would boil off through a pressure regulator valve as use-once coolant (I assume it would be used on the sun-illuminated side of a vehicle). I do not think that this should weigh more than 1kg, based on current video/camcorder technology (1kg is on the large side), and be maximum 30x30x10 cm in size (deliberately large to minimize surface load in case of unintended contact) with some sort of sunshade sail on the sun-facing backside. I was thinking of a blowfish-like device that would inflate a balloon around itself for thermal and impact protection reasons. Peter -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Since it would only have to work for maximum 20-30 minutes, thermal management, batteries etc would not be so hard to manage. Or you could only run it at "night" (which is always not that far away, in LEO.) I do not think that this should weigh more than 1kg... I *think* you seriously underestimate the amount of nitrogen it would take to push around a kg of device for 20 minutes. Although perhaps that could be minimized by limitting accelerations to small values. Maybe it could operate like that remote-control UFO I was seeing in the stores around xmas: continually rotating while using a "reference direction" to control the motors and the actual flight... BillW -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> Since it would only have to work for maximum 20-30 minutes, thermal > management, batteries etc would not be so hard to manage. > >Or you could only run it at "night" (which is always not that far away, >in LEO.) No, you want to be able to see, so it has to be done in the sun. Otherwise the gizmo needs lights and that will seriously change the power requirements. >I *think* you seriously underestimate the amount of nitrogen it would >take to push around a kg of device for 20 minutes. Although perhaps that >could be minimized by limitting accelerations to small values. Maybe it >could ... Because the idea is to scan the underside for problems it would likely not go faster than 1m/sec in any direction at any time. 1m/sec is probably on the fast side. The amount of propellant can be calculated from this. It should be small enough (remember it only needs to change direction a few dozen times - it will be coasting most of the time and it only needs to make maximum two passes to identify problems and some hovering to inspect them - the camera ouput would be taped all the time onboard). I do not know about the impulse of nitrogen jets etc but the energy required to reverse the path 180 degrees is 1 Joule with 1kg vehicle mass and 1m/sec. This looks low enough to be do-able several dozen times with a small nitrogen tank at very high pressure (5000 psi or more), and if flying slower the required energy will be much smaller (required energy is proportional to speed squared). Maybe they could use another gas as propellant (Argon for example = 1.4 times density of N - or go all the way and use Xe which is rare and expensive - but they are NASA). Funny I have never heard of Xe used as propellant (it is probably too expensive but the density is nearly five times that of Nitrogen). And the smaller the mass of the vehicle the better. Again based on current camcorder technology a vehicle with the given characteristics should be around 300 grams (w/o nitrogen tank and thermal management, but including battery good for 40+ minutes). Basically it would be a wireless stereo camera with remote jet control and little else. It could also be used for general inspection work on the space station etc, saving evas and spy sattelite propellant. For multi-use some sort of recovery system should be provided, and a way to change batteries and propellant tanks (probably by hand during eva). But this is not necessary for this use (shuttle exterior inspection). Peter -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

rad0 wrote: >This surpises me, in hindsight of course. I've heard that what they call >foam is more like concrete. > > The foam is very lightweight. My understanding is that on humid days (aren't all days humid down there? ;-) ) the foam can still become encrusted with ice in some spots. My own intuition tells me that sprayed on foam, even carefully applied, may not always stick properly or prevent ice buildup from moisture. -Adam -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Hi All! > rad0 wrote: > > >This surpises me, in hindsight of course. I've heard that what they call > >foam is more like concrete. At those speeds *anything* is 'like concrete.' On Sat, 15 Mar 2003, M. Adam Davis wrote: > The foam is very lightweight. In the news I've seen the word polyurethane mentioned and I'm sure there're many kinds but probably all very similar. It's very light but also very hard, dense and strong, meaning you can't just poke a finger into it (or the speeds in the atmosphere would just tear it off with the wind turbulence.) The stuff I worked with, you can snap a 1^2" thick stick of it in two hands, maybe 3^2" over the knee, but 6^2" is quite strong. My Dad did a little experiment with it when I was a kid. He had a piece of aluminum honeycomb material about 1"x6"x24". Very light and flexible, the walls of the cells were very thin. He filled the cells with polyurethane. It became totally inflexible and powerful strong. We set it up between two bricks and stand on it and jump and down and it didn't even flex never mind break. I'd also guess that the rason they don't put the insulation -inside- the tank is because it'd require yet another sealed inner liner with associated weight and reliability problems. The surface of the foam was actually very fragile, could scratch plastic flakes/dust off by just touching it, and they -can't- allow that to get into the fuel. It's clog things, leave residue all around, and probably affect the burn mixture (it's flammable.) The point being that's it's very strong, but only up to a point after which it's just dust. > My understanding is that on humid days (aren't all days humid down > there? ;-) ) the foam can still become encrusted with ice in some > spots. > > My own intuition tells me that sprayed on foam, even carefully applied, > may not always stick properly or prevent ice buildup from moisture. Good point. So if the adhesion is a little down and the frost/ice is a little up then parameters could easily be outside design safety limits. Gee, can anyone spell o-ring? :/ Ice or foam though doesn't matter much because if whatever fell off the tank hit the wing it'd do more or less the same damage. The surface of those black tiles can be scratched with a fingernail. Have a :) day! jb -- jim barchuk jbKILLspamjbarchuk.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Maybe I was not clear but I was talking about a robot camera to be used in space, after the launch, to check for damage. Not about the foam on the tank. The Saturn/Apollo launch vehicle had a similar weight to the Shuttle (about 2500 tons vs 2000), and payload weight (about 55 tons) and they used insulation on the inside. The Shuttle is about 2 times more efficient (payload/total mass) than Apollo. Maybe this (the exterior insulation) is an important factor. I searched a little and there are several good documents about this. A lot of numbers about the Shuttle are here: http://users.commkey.net/Braeunig/space/specs/shuttle.htm The tank insulation is said to be polyurethane foam, 25mm thick. Peter -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam.....mitvma.mit.edu with SET PICList DIGEST in the body

Peter L. Peres wrote: {Quote hidden}> I was wondering why they do not have a remote controlled gizmo eject > and fly around the ship to inspect for damage. It could be small and > light enough and only capable of slow speed (restricted nitrogen > jets) so it would not be able to cause damage even if it would > contact the ship. It could be tested before being allowed to go to > the sensitive part of the ship. > > I think that a device roughly bathroom sponge sized with a small color > camera (maybe stereo camera) and nitrogen jets would be possible. It > could be untethered and commanded to lose itself by expelling the > remaining nitrogen when finished with inspections, in a safe > direction. Since it would only have to work for maximum 20-30 > minutes, thermal management, batteries etc would not be so hard to > manage. Maybe it would have a small amount of water that would boil > off through a pressure regulator valve as use-once coolant (I assume > it would be used on the sun-illuminated side of a vehicle). > > I do not think that this should weigh more than 1kg, based on current > video/camcorder technology (1kg is on the large side), and be maximum > 30x30x10 cm in size (deliberately large to minimize surface load in > case of unintended contact) with some sort of sunshade sail on the > sun-facing backside. I was thinking of a blowfish-like device that > would inflate a balloon around itself for thermal and impact > protection reasons. > > Peter By the point of view of a several million dollars vessel, one SHOULD not need to worry about external damages, by the way, you would not build up a so expensive vehicle, fragil, right? By the point of view of human exploration, yes, not only super-bond, but other very heat resistant glues should be available at board. It was amazing to see at that last minutes image recording, some cables overhead in the cockpit secured in place with simple and bare "duct tape"... did you see it? I said it before, with the actual cost and technology of cameras, I can't understand why they don't use them more frequently, even to make pictures of the shuttle from 100 meters away, just launch the cameras once in orbit, several ways to control them, including motion, it should be not that difficult, right? Or perhaps it is only me who can buy a $50 2.4GHz wireless camera at any Radio Shack? Wagner -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email EraseMElistservspam_OUTTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

I received this message from Road Runner. Please check your system for a virus Ted Peter L. Peres wrote: >file attachment: fdimag15.zip.pif > >This e-mail in its original form contained one or more attached files that were infected with the W32.Bugbear.B@mm virus or worm. They have been removed. >For more information on Road Runner's virus filtering initiative, visit our Help & Member Services pages at http://help.rr.com, or the virus filtering information page directly at http://help.rr.com/faqs/e_mgsp.html. > > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> I received this message from Road Runner. Please check your system for a > virus > Ted I have checked. I have also received the same message, also from road runner, but my spam/virus filter killed it and I only saw the report ;-) I run Linux and that virus is a windoze one. So I can't get it even if it gets through the filters and I open it (how ? - pif and exe files do not run on Linux). Whenever you see a message like that (a blast from the past) check the headers carefully. This type of virus takes headers from saved messages and re-sends them with virus inside. They always come from someone OTHER than who appears on the envelope as a sender. The strongest clue is the first (lowest) email hop in the header and the fact that the apparent poster's domain is not in it at all usually. Peter -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservspam_OUTmitvma.mit.edu with SET PICList DIGEST in the body

> It does not show a "to" address in the header on OE6. I was kind of > curios how it found me... The to address header is optional ;-) It found you by sending a RCPT TO: with your address in a SMTP negotiation. Why would it put in a to: address when it is not required. You can look up other scary things that can happen with email by searching the net for a series of articles about 'when I was in siberia' and email. I do not remember the exact wording. The current email formats are governed by obsolete standards which were never designed to cope with spam, broken mime encoders and malicious users or viruses. The results show. My mail filter currently contains over 8k of keywords to stop junk mail and it only stops 50% of spam traffic ... Peter -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads