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![]() Sorry for taking so long, but I was lining up some ducks... In article , "John Mullen" writes: "Peter Stickney" wrote in message ... In article , "John Mullen" writes: "Emilio" wrote in message ... Actually they admitted they copied the US Shuttle. More I think about Buran, it is clear that the politician who decided to "copy" the shuttle and not the engineers. Russian industry simply was not setup to produce space qualified $20 nuts and bolts like we do. If they made special run to make such nuts and bolts it would have cost them $100 a peace. Buran must have been reengineered to be able for them to build it there. That's a problem though. It's going to get heavier than a US shuttle. Reentry and flight parameters will no longer be the same do to added weight. It's amazing that they made it to work in the first place. Actually, it was a superior design to the STS it was copied from. Heavier payload, more crew space and less rinky-dink stuff to blow up like the ET and the SRBs. Just teh Big Honkin' booster it was hooked to. Both configurations have their advantages, and their risks. I can't think of any advantages to the STS's layout. What did you mean here? Just off the top of my head - better alignment of teh Main Engine's thrust lines with the CG of the entire stack. This gives you less problems with control, and more tolerance of off-normal conditions. (Such as losing a Main Engine - it's happened once on STS) Concentration of teh Guidance & COntrol systems in a single, integrated system, rather than having two independant systems that have to try to talk to each other. Keeping the expensive, reusable bits in one place, and throwing away the cheap stuff. (As it turns out, this didn't work out as well as originally expected - rather than a clear advantage wrt reusing STS SSMEs vs. the Energia's cheaper, (but still not cheap) expendables, it seems to be pretty much of a wash. Well, the Astronauts never flew it. That tells you something. Buran: 1 unmanned flight, total success. Not a total success - teh flight article was structurally damaged on re-entry. I don't know if repair was possible. That is news to me. See for example: http://www.astronautix.com/craft/buran.htm Mark Wade quote excized Could you be mistaken? Or is this fairly new info? If the latter, I would be interested in knowing your source. No, I'm not mistaken. It's not new info, although teh (then) Soviets weren't too big on publishing it. There are various sources, but the best place to go, if you can read Russian, is the Official Buran site: Http://www.buran.ru/ Even if you don't read Russian, here are some post-flight images of Buran: http://www.buran.ru/images/jpg/posle01.jpg http://www.buran.ru/images/jpg/posle02.jpg http://www.buran.ru/images/jpg/posle03.jpg http://www.buran.ru/images/jpg/posle04.jpg http://www.buran.ru/images/jpg/posle05.jpg http://www.buran.ru/images/jpg/posle06.jpg http://www.buran.ru/images/jpg/posle07.jpg http://www.buran.ru/images/jpg/posle08.jpg http://www.buran.ru/images/jpg/posle09.jpg http://www.buran.ru/images/jpg/posle10.jpg http://www.buran.ru/images/jpg/posle11.jpg http://www.buran.ru/images/jpg/posle12.jpg http://www.buran.ru/images/jpg/posle13.jpg http://www.buran.ru/images/jpg/posle14.jpg http://www.buran.ru/images/jpg/posle15.jpg While most of them are pretty ordinary - some damage occurs on any flight, pay special attention to image 15. That's a breach of teh wing structure, caused by poor joints between the Carbon-Carbon Leading Edge and the Ceramic Tiles that cover most of the wing skin. The Russians were fairly coy about the internal damage, but from the scarring and marks left by hte exiting material, it wasn't trivial. At best, you're talking about rebuilding/replacing the wing. At worst, it goes to Monino and you fly the #2 flight article. Thay're lucky that it occurred out toward the wingtip. If it had been where the chine & the wing come together, where the shock impingement from the bow shock occurs, (And where Columbia's damage occurred), it would have been much, much worse. STS ~100 manned flights, two total losses, 14 deaths. A hair over a 98% success rate, a bit better than Soyuz (Which also had 2 fatal flights, with 100% crew loss on each, (But smaller crews), and several launch aborts. And a number of nasty landing incidents. Really? I cannot easily find a total for the number of Soyuz missions but feel sure it must be way over the 100-odd of the STS. Do you have better figures? Currently, the number is 90 Soyuz flights, and 112 Shuttle flights. http://space.kursknet.ru/cosmos/english/main.sht hads been keeping a running total, valid through late May, 2004. (no flights since then) And to me the survivable aborts are an indication of the robustness of the 1960s design. The people on Challenger would have loved a surviveable abort system. The people on Columbia would have loved merely to have suffered a nasty landing incident. They're not really relevant - every vehicle, from a Skateboard to a Shuttle, has failure modes which are not survivable. If the aborts had taken place at a slightly different time, or the reentry and landing incidents, like the time a Soyuz Service Module didn't detach after retrofire, causing the Soyusz to reenter not heatshield first, but Aluminum hatch cover first (The SM burned away, allowing the spacecraft to reorient itself before the crew was lost), and the guidance problems that have caused some reentries to occur hundreds of miles off from their targets could very easily have been much worse. Aviation, and especially Spaceflight, is all about tradeoffs. What sorts of system could have been aboard Challenger that would have extended the survival envelope significantly, and wouldn't have been a hazard during most of the flight? And which wouldnt' require some compromise of the stucture? What system could possible have turned Columbia's loss to a nasty landing incident? I don't see any systems that would allow a successful bailout at Mach 25/200,000'. (You could, I suppose, postulate something like MOOSE, but that's only useful before the retro burn occurs) (I never mentioned Soyuz btw!) Whenever the "Two Accidents, 100% crew loss" line comes up, a comparison with Soyuz reliability is not far behind. There's no reasonable comparison to anything else, after all. Buran made 1 limited flight, got broken, although the full extent still isn't known, during that flight, and sat in the assemble building until the building collapsed on it. There's no objective indication that the expendable Soyuz capsule is any safer than the STS. Er.. how about the fact that the STS is currently grounded for safety improvements after the last fatal crash? Leaving Soyuz as the world's only manned orbital vehicle, other than the Chinese and maybe Bert Rutan! That's not objective, it's subjective. Because the Russians, (and for that matter, us) are willing to accept the risks that flying Soyuz right now represent. That doesn't make it risk-free. Anytime you fly anything, whether it's a kite or a 747 with 500 people aboard, or a spacecraft, you run the risk of a fatal crash. If you fly something enough, it becomes pretty much certain that you'll crash it. To a large extent, it's a question of whether the risk is perceived to be sufficiently minimized. Here in the U.S., we see that there are steps that can be taken to reduce the risk of Shuttle flights, and we'er willing to take the time to implement them. I don't think there's a lot that you can do to make a Soyuz less risky. (Which does not make it risk free). As for Burt Rutan, please don't make the mistake that SpaceShipOne is the harbinger of entry into orbit. It's not. The design is very heavily optimized for a single, very limited goal - getting an X-prize equivalent mass to 100 km altitude. The peak Mach Numbers for SS1 are down around Mach 2, the materials are all conventional, and the "shuttlecock" re-entry profile isn't going to hack Mach 25. Don't get me wrong, it's an excellent achievment, but useful Space Travel it isn't. I'd say the Russians realised they had no need of a shuttle and quit while they were ahead. More like they couldn't afford it. Both Buran and Energia (The booster) Well sure. It is true that their country did collapse during the devlopment of the Buran and Energia projects, leading to their cancellation. My point was that this wasn't because they were inferior kit, quite the contrary. But there also isn't enough sample size to claim with any validity that it was superior, either. -- Pete Stickney A strong conviction that something must be done is the parent of many bad measures. -- Daniel Webster |
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"Peter Stickney" wrote in message
... Sorry for taking so long, but I was lining up some ducks... (snip) I can't think of any advantages to the STS's layout. What did you mean here? Just off the top of my head - better alignment of teh Main Engine's thrust lines with the CG of the entire stack. This gives you less problems with control, and more tolerance of off-normal conditions. (Such as losing a Main Engine - it's happened once on STS) The Buran didn't have Main Engines on the Shuttle. One of its major advantages to me, not having all that plumbing to the ET... Concentration of teh Guidance & COntrol systems in a single, integrated system, rather than having two independant systems that have to try to talk to each other. Keeping the expensive, reusable bits in one place, and throwing away the cheap stuff. (As it turns out, this didn't work out as well as originally expected - rather than a clear advantage wrt reusing STS SSMEs vs. the Energia's cheaper, (but still not cheap) expendables, it seems to be pretty much of a wash. Exactly. Although the original concept of the STS being a reuseable vehicle was excellent, the compromises made during the design process (many at the behest of the DoD) negated them almost entirely. Well, the Astronauts never flew it. That tells you something. Buran: 1 unmanned flight, total success. Not a total success - teh flight article was structurally damaged on re-entry. I don't know if repair was possible. That is news to me. See for example: http://www.astronautix.com/craft/buran.htm Mark Wade quote excized Could you be mistaken? Or is this fairly new info? If the latter, I would be interested in knowing your source. No, I'm not mistaken. It's not new info, although teh (then) Soviets weren't too big on publishing it. There are various sources, but the best place to go, if you can read Russian, is the Official Buran site: Http://www.buran.ru/ Even if you don't read Russian, here are some post-flight images of Buran: http://www.buran.ru/images/jpg/posle01.jpg http://www.buran.ru/images/jpg/posle02.jpg http://www.buran.ru/images/jpg/posle03.jpg http://www.buran.ru/images/jpg/posle04.jpg http://www.buran.ru/images/jpg/posle05.jpg http://www.buran.ru/images/jpg/posle06.jpg http://www.buran.ru/images/jpg/posle07.jpg http://www.buran.ru/images/jpg/posle08.jpg http://www.buran.ru/images/jpg/posle09.jpg http://www.buran.ru/images/jpg/posle10.jpg http://www.buran.ru/images/jpg/posle11.jpg http://www.buran.ru/images/jpg/posle12.jpg http://www.buran.ru/images/jpg/posle13.jpg http://www.buran.ru/images/jpg/posle14.jpg http://www.buran.ru/images/jpg/posle15.jpg While most of them are pretty ordinary - some damage occurs on any flight, pay special attention to image 15. That's a breach of teh wing structure, caused by poor joints between the Carbon-Carbon Leading Edge and the Ceramic Tiles that cover most of the wing skin. The Russians were fairly coy about the internal damage, but from the scarring and marks left by hte exiting material, it wasn't trivial. At best, you're talking about rebuilding/replacing the wing. At worst, it goes to Monino and you fly the #2 flight article. Thay're lucky that it occurred out toward the wingtip. If it had been where the chine & the wing come together, where the shock impingement from the bow shock occurs, (And where Columbia's damage occurred), it would have been much, much worse. Interesting. STS ~100 manned flights, two total losses, 14 deaths. A hair over a 98% success rate, a bit better than Soyuz (Which also had 2 fatal flights, with 100% crew loss on each, (But smaller crews), and several launch aborts. And a number of nasty landing incidents. Really? I cannot easily find a total for the number of Soyuz missions but feel sure it must be way over the 100-odd of the STS. Do you have better figures? Currently, the number is 90 Soyuz flights, and 112 Shuttle flights. http://space.kursknet.ru/cosmos/english/main.sht hads been keeping a running total, valid through late May, 2004. (no flights since then) And to me the survivable aborts are an indication of the robustness of the 1960s design. The people on Challenger would have loved a surviveable abort system. The people on Columbia would have loved merely to have suffered a nasty landing incident. They're not really relevant - every vehicle, from a Skateboard to a Shuttle, has failure modes which are not survivable. If the aborts had taken place at a slightly different time, or the reentry and landing incidents, like the time a Soyuz Service Module didn't detach after retrofire, causing the Soyusz to reenter not heatshield first, but Aluminum hatch cover first (The SM burned away, allowing the spacecraft to reorient itself before the crew was lost), and the guidance problems that have caused some reentries to occur hundreds of miles off from their targets could very easily have been much worse. Aviation, and especially Spaceflight, is all about tradeoffs. What sorts of system could have been aboard Challenger that would have extended the survival envelope significantly, and wouldn't have been a hazard during most of the flight? Simple. A parachute for each crew member and a bail out pole, as they fitted post-Challenger, might have at least given them a sporting chance. And which wouldnt' require some compromise of the stucture? What system could possible have turned Columbia's loss to a nasty landing incident? I don't see any systems that would allow a successful bailout at Mach 25/200,000'. (You could, I suppose, postulate something like MOOSE, but that's only useful before the retro burn occurs) (I never mentioned Soyuz btw!) Whenever the "Two Accidents, 100% crew loss" line comes up, a comparison with Soyuz reliability is not far behind. There's no reasonable comparison to anything else, after all. Buran made 1 limited flight, got broken, although the full extent still isn't known, during that flight, and sat in the assemble building until the building collapsed on it. There's no objective indication that the expendable Soyuz capsule is any safer than the STS. Er.. how about the fact that the STS is currently grounded for safety improvements after the last fatal crash? Leaving Soyuz as the world's only manned orbital vehicle, other than the Chinese and maybe Bert Rutan! That's not objective, it's subjective. Because the Russians, (and for that matter, us) are willing to accept the risks that flying Soyuz right now represent. That doesn't make it risk-free. Anytime you fly anything, whether it's a kite or a 747 with 500 people aboard, or a spacecraft, you run the risk of a fatal crash. If you fly something enough, it becomes pretty much certain that you'll crash it. To a large extent, it's a question of whether the risk is perceived to be sufficiently minimized. Here in the U.S., we see that there are steps that can be taken to reduce the risk of Shuttle flights, and we'er willing to take the time to implement them. I don't think there's a lot that you can do to make a Soyuz less risky. (Which does not make it risk free). Granted. As for Burt Rutan, please don't make the mistake that SpaceShipOne is the harbinger of entry into orbit. It's not. The design is very heavily optimized for a single, very limited goal - getting an X-prize equivalent mass to 100 km altitude. The peak Mach Numbers for SS1 are down around Mach 2, the materials are all conventional, and the "shuttlecock" re-entry profile isn't going to hack Mach 25. Don't get me wrong, it's an excellent achievment, but useful Space Travel it isn't. I still think it is a very good step in the right direction. Waiting with bated breath... I'd say the Russians realised they had no need of a shuttle and quit while they were ahead. More like they couldn't afford it. Both Buran and Energia (The booster) Well sure. It is true that their country did collapse during the devlopment of the Buran and Energia projects, leading to their cancellation. My point was that this wasn't because they were inferior kit, quite the contrary. But there also isn't enough sample size to claim with any validity that it was superior, either. No. I still think though that is was a shame it wasn't persevered with. John |
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In article ,
"John Mullen" writes: "Peter Stickney" wrote in message ... Sorry for taking so long, but I was lining up some ducks... (snip) I can't think of any advantages to the STS's layout. What did you mean here? Just off the top of my head - better alignment of the Main Engine's thrust lines with the CG of the entire stack. This gives you less problems with control, and more tolerance of off-normal conditions. (Such as losing a Main Engine - it's happened once on STS) The Buran didn't have Main Engines on the Shuttle. One of its major advantages to me, not having all that plumbing to the ET... You asked what advantages there were for the STS layout over the Bura/Energia. To be more explicit, the STS's placement of the main engines in the Orbiter give a superior thrust line through the CG of teh stack as a whole, leading to teh advantages in control and tolerance of failure. The Energia setup, with the Main Engines on what is essentially the external tank section of teh stack, has the advantage in terms of operational flexibility - you can use an Energia stack to launch something other than Buran, for a cargo-only flight. The problem is that Energia's cargo is still parallel staged, (side-by-side), and the problems of guidance & control of the stack, and tolerance of failures remain. While teh plumbing of teh external tank to the Shuttle is a bit complicated, it hasn't been much of a factor wrt flying the Shuttle. It could probably benefit from some of the Russian's rather better crygenic plumbing connectors, though. Concentration of the Guidance & Control systems in a single, integrated system, rather than having two independant systems that have to try to talk to each other. Keeping the expensive, reusable bits in one place, and throwing away the cheap stuff. (As it turns out, this didn't work out as well as originally expected - rather than a clear advantage wrt reusing STS SSMEs vs. the Energia's cheaper, (but still not cheap) expendables, it seems to be pretty much of a wash. Exactly. Although the original concept of the STS being a reuseable vehicle was excellent, the compromises made during the design process (many at the behest of the DoD) negated them almost entirely. The biggest problems with Shuttle reusibilit costs weren't physical, but people/management/the economy in general - Labor costs in the 1970s skyrocketed, and that put the overhead costs of teh refit & refurbish cycle through the roof. They're not really relevant - every vehicle, from a Skateboard to a Shuttle, has failure modes which are not survivable. If the aborts had taken place at a slightly different time, or the reentry and landing incidents, like the time a Soyuz Service Module didn't detach after retrofire, causing the Soyusz to reenter not heatshield first, but Aluminum hatch cover first (The SM burned away, allowing the spacecraft to reorient itself before the crew was lost), and the guidance problems that have caused some reentries to occur hundreds of miles off from their targets could very easily have been much worse. Aviation, and especially Spaceflight, is all about tradeoffs. What sorts of system could have been aboard Challenger that would have extended the survival envelope significantly, and wouldn't have been a hazard during most of the flight? Simple. A parachute for each crew member and a bail out pole, as they fitted post-Challenger, might have at least given them a sporting chance. I rather doubt it. bailing out from a Shuttle, or any large airplane, such as a KC-135, requires the the aircraft be in steady, stable flight - not a piece of wreckage tumbling through the sky at more than Mach 3. Then you've got the problems that come from jumping above 50,000' (Note that the Challenger's cabin section's trajectory peaked somewhere around 100,000' - anybody jumping would follow the same tarajectory fairly closely - there isn't much drag up there.) Any escape mechanism used in the region where teh Challenger's loss occurred has to provide Pressure, Oxygen, protection from the cold - Jumping at 50,000' and free-falling means that you'll most likely freexe to death in short order - and protection from the prepellant residues of the boost motors, which are extremely corrosive. Ejection seats don't add much in the way of a _usable_ escape envelope, and add in all the dangers that accompany hot seats in airplanes - the risks of catastrophe due to inadvertantly activating a seat - not just the big things like, say, blowing a section of the cabin roof off with Primacord in orbit, but if setting off pyros & such in the cabin atmosphere, would increase teh overall danger. Capsules would, at a great penalty in wieht and structure, extend the envelope a bit further, but no much - the big problem with ejecting much higher/faster than Challenger was going when the breakup occurred is that the deceleration incurred on an unmodified ballistic trajectory are on teh order of 50-60Gs, and aren't survivable. Adding the ability to change the trajectory would make any such system too heavy and complicated to be worth it. As for Burt Rutan, please don't make the mistake that SpaceShipOne is the harbinger of entry into orbit. It's not. The design is very heavily optimized for a single, very limited goal - getting an X-prize equivalent mass to 100 km altitude. The peak Mach Numbers for SS1 are down around Mach 2, the materials are all conventional, and the "shuttlecock" re-entry profile isn't going to hack Mach 25. Don't get me wrong, it's an excellent achievment, but useful Space Travel it isn't. I still think it is a very good step in the right direction. Waiting with bated breath... We've been through this before - technologically, SS1 is less of a challenge than the X-15, 45 years ago. While SS1's performance will be sufficient to win the X-Prize, it won't yield a useful, productive system. I'm not seeking to minimize the achievement, but let's not blow it up beyond what it really is. In Buran and Energiya No. I still think though that is was a shame it wasn't persevered with. They were keeping it around, stored against the possibility that there may be some interest in the future. But the Assemply Building collapsed on it. If they couldn't keep a fairly new building together, I rather doubt that they were going to be re-starting any serious, and expensive development programs anytime soon. -- Pete Stickney A strong conviction that something must be done is the parent of many bad measures. -- Daniel Webster |
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