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#31
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Jeff Findley wrote:
I agree with your point, but you keep asserting that the US could do better on its first try than the Russians have done with a series of Elektron units that have actually been flown in zero gravity. That's a completely baseless assertion. One must, however, consider the *possibility* that with all its experiences, Russia never bothered to change the design of the unit to prevent problems, having decided it is simpler to just fix them as they arise in space. In such a theoretical scenario, it is therefore possible for the USA to use that acquired knowledge and design its new system that turns out to be more reliable than the russian one. This assumes that the design of the US O2 generator would not have been cast in stone prior to ISS being crewed and feedback on design flaws of Elektron being returned to NASA via US crewmembers. The thing is that we just don't know. But we do know that systems that handle liquids and especally those with bubbles are very different in space than on earth. And unless the system is built in transparent aluminium, it is also very hard for the crew members to actually see what happens inside to cause the problem. |
#32
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"John Doe" wrote in message ... Mike Walsh wrote: To the Russians credit, they actually have a working system up there and if their Elektron fails then they might have to burn one of their oxygen generating "candles" that have worked so well in the past, at least if they didn't cause a major fire. They are using O2 from Progress right now, from what I have read. In terms of the O2 candle fire, as long as it doesn't occur again over a statistically significant period of time , one can conclude that the russians have learned their lesson and have changed procedures/design to help prevent this from occuring again. That does not follow at all. From what I have read, the main procedure change was not to use old canisters or canisters that didn't have good tracking data. This is not the same as determining the cause of the problem and then fixing it. The major fire on Mir showed that a malfunctioning capsule can produce a deadly stream of flame that will continue unabated until the oxygen supply runs out. There is nothing that can be done to stop it once it gets thoroughly started. You may be able to damp it and cool it down so that it goes out if there is a minor fire at startup but there is no way it can be stopped with the equipment aboard a space station, and rather doubtful even with a ground fire fighting system. What should have been done is that a series of attempts should have been made with a set of "doubtful" canisters to see if the problem can be duplicated and a cause determined. If this has not been done then the "candles" are a potential disaster just waiting for the wrong series of events to happen. One negative is that I don't believe we even know whether or not Russia has anyone actually spending the money to have any organization actively trying to improve Elektron. Hard to improve something before you know what actually happens to cause the problem. And that is exactly what the crews are doing right now. And yes, judging from comms, they do have engineers in russia providing support. But again, until they know what exactly goes wrong in 0g, the ground engineers can't really fix anything. It certainly helps to have the 0g data available, but it isn't true that they have to know exactly what went wrong before trying to fix it. It is true that they won't know whether or not the fix works until they actually keep it running in 0g. It appears to me that rather than accepting the Russian equipment as super-qualified because it has been around for a long time that a combined U.S. Russian program to improve certain specific capabilities (Elektron, space suits, oxygen generating devices) could be very productive. No offense to americans, but they have exactly 0 experience with O2 generators actually running in 0g, unless you count the handfull of US crewmembers who have worked on elektron. So the USA really couldn't contribute much to fixing Elektron problems. Well, someday, somehow U.S. engineers will require similar devices and observing and troubleshooting the existing Elektron is a way to do this. You seem to assume that the USA engineers on the ground couldn't help fixing Elektron problems because they don't have experience running them. I believe the Russian engineers have exactly the same amount of "hands on" 0g experience as the US engineers (none) unless they have a former cosmonaut working the problem. If the U.S. engineers lack anything it is the design and construction details of the Elektron. And very likely the Russians don't send their engineering reports to NASA. Mike Walsh (Snipped out the rest) |
#33
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"dave schneider" wrote in message om... "Mike Walsh" wrote: [...] if their Elektron fails then they might have to burn one of their oxygen generating "candles" that have worked so well in the past, at least if they didn't cause a major fire. AIUI, those "candles" are similar to US oxygen generators, including the one that left a hole in the Everglades that included a bunch of human remains. Russia has no lock on mistakes with these familiar and well-understood devices, but they do lead in micro-g experience with uncontained flame; one hopes that the lessons learned from that incident are still learned. This isn't exactly comforting information. If these are such familiar and well-understood devices (and really similar to the Russian oxygen generator) then perhaps someone really knows what happened on board Mir, but I haven't read any explanation of it. Mike Walsh |
#34
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"John Doe" wrote in message ... Jeff Findley wrote: I agree with your point, but you keep asserting that the US could do better on its first try than the Russians have done with a series of Elektron units that have actually been flown in zero gravity. That's a completely baseless assertion. One must, however, consider the *possibility* that with all its experiences, Russia never bothered to change the design of the unit to prevent problems, having decided it is simpler to just fix them as they arise in space. In such a theoretical scenario, it is therefore possible for the USA to use that acquired knowledge and design its new system that turns out to be more reliable than the russian one. Assuming that the information is available to the US and that Russia is not holding the necessary data from the ISS from NASA. On Mir it was Russia's station and their program so they could do what they wished. ISS is supposed to be a cooperative program. Not sure whether NASA recognizes this either or what the Congressional limits are on information interchange. This assumes that the design of the US O2 generator would not have been cast in stone prior to ISS being crewed and feedback on design flaws of Elektron being returned to NASA via US crewmembers. The thing is that we just don't know. But we do know that systems that handle liquids and especally those with bubbles are very different in space than on earth. And unless the system is built in transparent aluminium, it is also very hard for the crew members to actually see what happens inside to cause the problem. In the long term I believe the ISS should be used to test new and improved hardware not saddled with the immediate operational requirement of providing breathing oxygen to the station. Mike Walsh |
#35
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John Doe wrote:
Derek Lyons wrote: Utterly false. Elektron has been *in orbit* for four years, not *in operation*. It's spent a goodly part of that time partially or completely inoperable. I wouldn't say that it spent such a great deal of time "inoperable". Problem is that you only hear about it when it has hiccups. But the rest of the time, it does function. Another partial truth that masks reality. We've heard a great deal about it because it has had ongoing hiccups. The'rest of the time' is meaningless. D. -- Touch-twice life. Eat. Drink. Laugh. |
#36
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"Mike Walsh" wrote:
That does not follow at all. From what I have read, the main procedure change was not to use old canisters or canisters that didn't have good tracking data. This is not the same as determining the cause of the problem and then fixing it. That's the situation in a nutshell. The cannisters are not fixed, nor are the causes of the fire known. D. -- Touch-twice life. Eat. Drink. Laugh. |
#37
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"Jeff Findley" wrote:
"Derek Lyons" wrote in message ... "Jeff Findley" wrote: Elektron works better than the US O2 generator. In the same sense that my buddies $150 beater (which blows smoke, leaks every fluid, runs crappy only when ambient is above 70F and runs not at all below that) works 'better' than the car which proceeded it does currently. (Said car tossed a rod.) Not at all. To my knowledge, the US has never operated an oxygen generation system in space, at least not one that cracks H2O to get O2 and H2. That's like saying you'd have complete confidence in the US ability to create a nuclear powered aircraft that couldn't possibly crash on the first flight. Utter bull****. If you note I compared an existing beater (Elektron) to a former, and no longer operating beater (the US system, which actually hasn't been tested yet and thus can be regarded as inoperable). Remember the "unsinkable" Titanic? It looked great on the drawing board, but sank anyway. In *this* ficton, 'unsinkable' was a term applied to the Titanic by the press, not by it's designers or operators. In fact, the damage control system on the Titanic functioned more-or-less as intended, the ship sunk slowly and in a controlled fashion. With discipline and more lifeboats, much fewer lives would have been lost. (Had doctrine been followed and the berg been taken head on, probably none would have been lost.) You can't say the same thing wouldn't happen to a US O2 generator when it is ran in zero gravity. Never claimed that the a US O2 generator would not have problems. My point is, and has long been, that Russian hardware isn't the all-singing all-dancing fully tested, fully proven, completely and utterly dependable system(s) that it's often portrayed as being in these groups and elsewhere. Statement like 'the Elektron is better than the US system' and 'the Elektron has years of operation' conceal and obscure the truth. I agree with your point, but you keep asserting that the US could do better on its first try than the Russians have done with a series of Elektron units that have actually been flown in zero gravity. That's a completely baseless assertion. That's a lack of reading comprehension on your part. I have never once asserted that a US unit, on it's first try, would perform any better than Elektron. Try reading my messages in this thread, and you'll note that I've hardly even mentioned the US unit. D. -- Touch-twice life. Eat. Drink. Laugh. |
#38
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Derek Lyons wrote:
That's the situation in a nutshell. The cannisters are not fixed, nor are the causes of the fire known. 1- Why would you think that they could be fixed in the first place ? It is a chemical reaction that generates O2 and HEAT. 2- Ever considered the possibility that there might be absolutely nothing wrong with the design of the canisters and that it was just a quality control/manufacturing defect ? (or as initialy reported, just used canisters that were too old). ? In the later case, it is *possible* that Russia has already tackled the cause with better process control on the ground and NASA not seeing any design changes. Remember that the Mir fire accident happened during a time when Russia was far more secretive than it is now, and it is likely we just won't know for a very long time. The one question to be asked is whether the mounting brackets on Alpha have been positioned so that should the same accident happen again, the flames would not burn critical items. |
#39
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John Doe wrote:
Derek Lyons wrote: That's the situation in a nutshell. The cannisters are not fixed, nor are the causes of the fire known. 1- Why would you think that they could be fixed in the first place ? It is a chemical reaction that generates O2 and HEAT. There is considerable difference between heat and the fire that occurred on MIR. 2- Ever considered the possibility that there might be absolutely nothing wrong with the design of the canisters and that it was just a quality control/manufacturing defect ? (or as initialy reported, just used canisters that were too old). ? So 'effin what? There was never a search to determine clearly what caused the fire. No discovery of causes means no correction to quality control and manufacturing processes to prevent the defect from happening again. In the later case, it is *possible* that Russia has already tackled the cause with better process control on the ground and NASA not seeing any design changes. That's an assumption utterly unsupported by any evidence. In fact, what evidence is available indicates that the Russians did no such thing. Remember that the Mir fire accident happened during a time when Russia was far more secretive than it is now, and it is likely we just won't know for a very long time. Wrong. The Soviets were quite open on many potentially embarrasing topics, and NASA colluded with them in covering them up and hiding them. The one question to be asked is whether the mounting brackets on Alpha have been positioned so that should the same accident happen again, the flames would not burn critical items. You really must work so hard to be so clueless. D. -- Touch-twice life. Eat. Drink. Laugh. |
#40
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"Jeff Findley" wrote in message . ..
When will the US O2 generator be operational on ISS so we can compare? Big laugh. There is no US O2 generator on ISS. There is a CO2 scrubber in the US Lab but that died after a couple of weeks (it hasn't worked in ages). There is an O2 supply in the US Quest airlock, but that apparently is out of order. Basically, US ECLSS suffers from the same fate as a lot of other US space technology, lots of systems engineering, great viewgraphs, but the damned thing doesn't work. |
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