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On Apr 8, 5:31*pm, bob haller wrote:
a contribuiting cause of challengers loss was very high crosswinds that helped unseal the o ring joint Pressure of SRB during operation: 912 psi Pressure on SRB at Max-Q: 5 psi (at 2,100 mph, 11 mile altitude) Pressure on SRB crosswind: 0.02 psi (at 34.6 mph (30 knots)) 30 knots is twice the cross wind speed allowed for shuttle operations. It produces a load of 3 pounds per square foot. A little less than 1/50th of a pound per square inch. Max Q on the spacecraft during ascent occurs at 11 miles altitude whilst traveling at 2,100 mph - at 5 psi. Of course the big daddy of them all, is the pressure inside the booster at 912 psi. As Richard Feynman famously pointed out, the cold launch temperatures caused the silicon based o-rings to be slow in filling the gaps allowing significant blow through of the rocket exhaust. This produced a torch like flame that cut through a support strut. The release of this strut caused the SRB to rotate around the remaining strut, puncturing the ET causing a massive hydrogen leak. The hydrogen flowed aft and was detonated by the exhaust causing the loss of the Challenger. My problem is the fact they used the SRBs in the first place. The low specific impulse of the solid propellant, combined with the need to make the entire casing withst tremendous temperatures and pressures, is the reason vonBraun and other rocket scientists from the 1960s onward, opposed the use of SRBs on the Shuttle. The US Army insisted on the use of SRBs because NASA and the Army are corrupt and they wanted to get kick backs from vendors they had in their pockets since world war two and the cold war producing things like the Nike missile propellant. vonBraun knew SRBs posed a significant safety risk. That didn't matter to NASA the US Army and the contractors who only wanted to dip their hands deeply in America's pockets at the least cost and risk to themselves. Maxime Faget designed the Mercury Capsule and contributed to both the Gemini and Apollo capsules. In response to the Space Group Task force he developed a $5.9 billion shuttle program that used existing engines and airframe technology and put 6 tons of payload into orbit and delivered a fleet of six orbiters for this price capable of 30 flights per year. He called this the DC-3 in honor of the first profitable commercial airliner - and in honor of Arthur Clarke's discussion of the topic in science literature of the day. Despite the workability of this approach, it wasn't good enough for the corrupt aerospace contractors of the day. The USAF famously argued for example, Faget's approach wasn't good enough because it had insufficient cross range. This despite the fact that cross-range has never ever been used on any mission. It was just an excuse to get budgets up and keep the kick backs flowing. http://en.wikipedia.org/wiki/Maxime_Faget Now, one might say this is a special case, and in honor of the nation and its space program we wouldn't talk too much about it. But, this isn't a special case. Its business as usual for a corrupt government that routinely lies to its people and bankrupts them for the illicit gain of a criminal regime that deserves jail time if not public hanging for what they've done, and are doing to our nation. Slimy bags of pus - the cointelpro sockpuppets operating in these groups have lied about me and what I have said in the past. http://www.pcworld.com/article/22259...r_the_cia.html They spread lies that I hate America for speaking the only truth that will give America a fighting chance. The fact is, those people are liars. I love my country and demand more of our government because of that. I refuse to sweep the bull**** under the rug anymore. We need to storm the Bastille and take back our power. As far as NASA is concerned, the presence of the SRBs on the shuttle and the extreme cost overruns of every NASA program since Nixon can't hide the truth of the long-standing corruption in every aspect of our military-industrial complex, including NASA. http://www.astronautix.com/graphics/0/2stsnar0.jpg http://www.astronautix.com/graphics/s/snar70.jpg Faget's DC-3 Shuttle featured an 2.4 m x 9.1 m payload bay, and a cross-range of just 300 km. The orbiter was equipped with two booster engines (XLR-129 modifications with 134,700 kgf), 2 orbital manoeuvring engines (RL10's with 6800 kgf), and six air-breathing engines (RB162-86's of 2,400 kgf burning JP-4 jet fuel). The booster would be equipped with booster engines, and Pratt and Whitney TF-B turbofan engines of 8,100 kgf for flyback. The launch scenario was for the booster to take the orbiter to altitude, release it, and then land at a down-range airfield. The Booster is then refueled downrange with jet fuel and flies back on its turbofan engines to the launch site. The orbiter had a 27.7 m wingspan with a 14 deg wing leading-edge sweep. The aluminium structure was protected by a silica-based thermal protection system. The booster would be 61.9 m long, have a 43 m wingspan with the same 14 degree sweep, and a total wing area of 264 square m. The leading edge would be protected by a pyrolised carbon laminate, and the lower surface by a silica-based thermal protection system. The payload would be delivered into a 500 km orbit at a 51 deg inclination. It was expected a fleet of six orbiters and four boosters would undertake 30 flights per year, each spacecraft having a life of 100 flights. It was expected a 48-hour reaction time between order for launch and launch would be possible. Total development cost of the orbiter was estimated as $2.77 billion, with the first article costing $171.2 million. The booster would cost $3.142 billion to develop, with a first article cost of $236 million. LEO Payload: 5,700 kg (12,500 lb) to a 500 km orbit at 28.00 degrees in 1985 dollars. Flyaway Unit Cost $: 38.000 million. Status: Study 1970. Gross mass: 998,775 kg (2,201,921 lb). Payload: 5,700 kg (12,500 lb). Height: 74.00 m (242.00 ft). Diameter: 5.08 m (16.66 ft). Thrust: 11,433.20 kN (2,570,286 lbf). Apogee: 500 km (310 mi). |
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On Apr 8, 5:44*pm, Fred J. McCall wrote:
bob haller wrote: a contribuiting cause of challengers loss was very high crosswinds that helped unseal the o ring joint Uh, no. -- "Ignorance is preferable to error, and he is less remote from the *truth who believes nothing than he who believes what is wrong." * * * * * * * * * * * * * * * *-- Thomas Jefferson Uh yes, airliners in the area reported large crosswinds that day, and after the joint sealed at launch the crosswinds stressed the joint helping it to unseal just before breakup. Fred believes he is a expert while really he knows little |
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On Apr 8, 6:25*am, David Spain wrote:
| wrote: Replay the tapes of the shuttle liftoffs and there are repeated episodes of O ring burn thru. I had a standing bet back in those years with a coworker that there would be a disaster on shuttle liftoff. NASA was massively "lucky" until it wasn't. Um, this statement leaves me puzzled. I don't have the data right in front of me at the moment, but IIRC the only Shuttle to have experienced complete burn-through through both sets of O Rings was 51-L (Challenger). Watching videos of any previous launches would not have shown anything because burn through did not occur. You did have "erosion" of the primary O ring but in all cases prior to 51-L the secondary ring did not fail, so I doubt that a video from outside the booster casing would reveal anything. The primary contributing factor as I remember it was joint rotation after ignition. This was not expected behavior for the SRB joints and was not compensated for during design of the original SRB tang-and-clevis segment joint. This was what was leading to primary O ring erosion in the first place, something that was NOT supposed to happen at all, even though two rings were there to provide redundancy. Couple that fact with the fact that 51-L was the coldest launch of Shuttle up to that time (it got a real cold soaking overnight the night before launch with unusually low temperatures for the Cape) and you got a situation where both rings failed. However the root cause of the problem was not the O-ring, but the case joint. It got a re-design after Challenger to fix the rotation issue that was causing primary ring erosion. AFAIK that cured the erosion problem. If anyone has data showing otherwise I'd sure like to see the cite. We've been over this territory in this newsgroup many many times. In system failures like this what we have seen now (twice) with Shuttle was that the problem is somewhat more psychological than scientific or engineering based. That is that idea that with complex systems with complex behaviors when confronted with a not well understood situation, there is a tendency to rely too heavily on past experience as proof that with the more successful experiences one obtains with a system with fuzzy behaviors the less likely that on the next launch there will be a problem. Just because you "got away with it" the last time or even the last fifty times doesn't mean it won't happen the next time. Trig, a standing bet like that with a co-worker, if you knew that this is what was going on, marks you as a good gambler. Dave What I recall was ignited flames along the side of the solid rocket boosters well above the bell nozzles as the shuttle was up and in full flight. This was well prior in the liftoff to space schedule prior to the Challenger disaster. It was early enough in time that 'Uncle Walter' was intoning his comments on the successful liftoff in one instances that I recall. they had eyes but they could not see..................Trig |
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On Apr 8, 1:00*pm, Fred J. McCall wrote:
David Spain wrote: | wrote: Replay the tapes of the shuttle liftoffs and there are repeated episodes of O ring burn thru. I had a standing bet back in those years with a coworker that there would be a disaster on shuttle liftoff. NASA was massively "lucky" until it wasn't. Um, this statement leaves me puzzled. I don't have the data right in front of me at the moment, but IIRC the only Shuttle to have experienced complete burn-through through both sets of O Rings was 51-L (Challenger). Watching videos of any previous launches would not have shown anything because burn through did not occur. You did have "erosion" of the primary O ring but in all cases prior to 51-L the secondary ring did not fail, so I doubt that a video from outside the booster casing would reveal anything. I believe that examination of past videos showed little pulses of 'smoke' from the SRB joints on some of them. -- "Insisting on perfect safety is for people who don't have the balls to * * live in the real world." * * * * * * * * * * * * -- Mary Shafer, NASA Dryden Smoke "hell" rather it was live flame for sure. |
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On Apr 9, 1:23*pm, Fred J. McCall wrote:
bob haller wrote: On Apr 8, 5:44 pm, Fred J. McCall wrote: bob haller wrote: a contribuiting cause of challengers loss was very high crosswinds that helped unseal the o ring joint Uh, no. Uh yes, airliners in the area reported large crosswinds that day, and after the joint sealed at launch the crosswinds stressed the joint helping it to unseal just before breakup. Fred believes he is a expert while really he knows little You really are a moron, aren't you? *Compare crosswind force to other forces acting on the vehicle during boost. *Crosswind is microscopic compared to the other aerodynamic forces. Provide a cite for your claim (because we all know you're too stupid to understand what you read). -- "Some people get lost in thought because it's such unfamiliar *territory." * * * * * * * * * * * * * * * * * * * --G. Behn so go back and check the vehicle first responded to those microscopic winds, the flame appeared, andf the stack disengrated,. you really need to go back and read the accident report |
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On Apr 9, 5:37*pm, |"
wrote: On Apr 8, 6:25*am, David Spain wrote: | wrote: Replay the tapes of the shuttle liftoffs and there are repeated episodes of O ring burn thru. I had a standing bet back in those years with a coworker that there would be a disaster on shuttle liftoff. NASA was massively "lucky" until it wasn't. Um, this statement leaves me puzzled. I don't have the data right in front of me at the moment, but IIRC the only Shuttle to have experienced complete burn-through through both sets of O Rings was 51-L (Challenger). Watching videos of any previous launches would not have shown anything because burn through did not occur. You did have "erosion" of the primary O ring but in all cases prior to 51-L the secondary ring did not fail, so I doubt that a video from outside the booster casing would reveal anything. The primary contributing factor as I remember it was joint rotation after ignition. This was not expected behavior for the SRB joints and was not compensated for during design of the original SRB tang-and-clevis segment joint. This was what was leading to primary O ring erosion in the first place, something that was NOT supposed to happen at all, even though two rings were there to provide redundancy. Couple that fact with the fact that 51-L was the coldest launch of Shuttle up to that time (it got a real cold soaking overnight the night before launch with unusually low temperatures for the Cape) and you got a situation where both rings failed. However the root cause of the problem was not the O-ring, but the case joint. It got a re-design after Challenger to fix the rotation issue that was causing primary ring erosion. AFAIK that cured the erosion problem. If anyone has data showing otherwise I'd sure like to see the cite. We've been over this territory in this newsgroup many many times. In system failures like this what we have seen now (twice) with Shuttle was that the problem is somewhat more psychological than scientific or engineering based. That is that idea that with complex systems with complex behaviors when confronted with a not well understood situation, there is a tendency to rely too heavily on past experience as proof that with the more successful experiences one obtains with a system with fuzzy behaviors the less likely that on the next launch there will be a problem. Just because you "got away with it" the last time or even the last fifty times doesn't mean it won't happen the next time. Trig, a standing bet like that with a co-worker, if you knew that this is what was going on, marks you as a good gambler. Dave What I recall was ignited flames along the side of the solid rocket boosters well above the bell nozzles as the shuttle was up and in full flight. This was well prior in the liftoff to space schedule prior to the Challenger disaster. It was early enough in time that 'Uncle Walter' was intoning his comments on the successful liftoff in one instances that I recall. they had eyes but they could not see..................Trig- Hide quoted text - - Show quoted text - yeah like shuttle returning with near wing burn thru ![]() for future ![]() its never been a problem before so all is well ![]() |
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On Apr 8, 12:31*pm, Fred J. McCall wrote:
Brad Guth wrote: On Apr 7, 6:36 pm, bob haller wrote: Buran test flight was unmanned and flew successfully. A capability the shuttle never had ![]() Because it didn't need it. There were never plans to fly the Shuttle unmanned. Why pay money for a feature you won't use? Brian The shuttle should of been built to fly unmanned if for no other reason than the ability to have the first flight unmanned for saftety. Besides it would of been a more versatile vehicle. and wouldnt of cost nmuch more. Exactly correct. *NASA even screwed up and had to put tonnes of lead in the nose. *Imagine what a truly good US/Russian shuttle fleet could have accomplished. Perhaps someone should put some lead ballast in your nose to make you better balanced? Hint: *Lead ballast is used to move the CG of the vehicle back to where it belongs based on how it's loaded. *This is not because "NASA even screwed up" any more than water ballast on ships is because ship designers "screwed up". *It's SUPPOSED to work like that. -- "Ignorance is preferable to error, and he is less remote from the *truth who believes nothing than he who believes what is wrong." * * * * * * * * * * * * * * * *-- Thomas Jefferson You fib, but what's new. The ballast was necessary because they screwed up. This ballast was a fixed amount of dead/inert mass. "Space shuttles carry two tons of lead blocks to compensate for designerror" A variable ballast mass would use something fluid. http://translate.google.com/# Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet” |
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Fred J. McCall wrote:
I believe that examination of past videos showed little pulses of 'smoke' from the SRB joints on some of them. This I buy as possible since we know the joint sealed up (for awhile) on 51-L after that puff of black smoke that occurred at SRB ignition. Smoke and or soot coming out of the case joint would have been a huge huge red flag in any scenario that didn't suffer from 'go fever'. In fact Fred, I believe I recall this being mentioned by others on this newsgroup a long time ago. | wrote: What I recall was ignited flames along the side of the solid rocket boosters well above the bell nozzles as the shuttle was up and in full flight. This was well prior in the liftoff to space schedule prior to the Challenger disaster. I cannot accept this without proof. For the simple reason that there was no 'blow by' of the secondary O rings on any flight prior to 51-L. If it was flames you were seeing coming from the SRB's it wasn't coming from the case joints. It was early enough in time that 'Uncle Walter' was intoning his comments on the successful liftoff in one instances that I recall. Uncle Walter was a space buff but not a rocket expert. Dave |
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David Spain wrote:
Fred J. McCall wrote: I believe that examination of past videos showed little pulses of 'smoke' from the SRB joints on some of them. This I buy as possible since we know the joint sealed up (for awhile) on 51-L after that puff of black smoke that occurred at SRB ignition. Smoke and or soot coming out of the case joint would have been a huge huge red flag in any scenario that didn't suffer from 'go fever'. In fact Fred, I believe I recall this being mentioned by others on this newsgroup a long time ago. Actually after reviewing some of the documents I'm not so sure I buy this. Doesn't seem possible to be able to get 'puffs of smoke' without having evidence of blow by which to get out of the case joint would have to have been past the secondary O-ring. In other words both would have had to have failed to seal at least for a bit. From what I've read so far that didn't happen to the case joints prior to 51-L. There was significant blow by of the primary o-ring and noted cases of thermal erosion of both o-rings on previous flights but no where have I read of a noted case of secondary o-ring blow by prior to 51-L. Any reputable/authoritative contrary cite appreciated. Were these puffs of smoke at ignition with the 4 Hz cycle expected? Were they from the case joints or the nozzle joints? Dave |
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Going back to Faget's DC-3 ship;
LUNAR OPERATIONS Payload Bay 9.1 m long x 2.4 diameter payload pay, carrying 5.68 metric tons of payload. Propellant Density A 3.5 m long x 2.4 diameter propellant tank carries 5.68 metric tons of of liquid hydrogen and liquid oxygen with a 6:1 oxidizer:fuel ratio. (hydrogen rich). Speed Requirement To go from Low Earth Orbit (LEO) to Lunar Free Return (LFR) trajectory requires a speed of 10.85 km/sec. This means a 3.5 km/sec increase in speed. Arriving at the Moon, a ship must impart another 2.4 km/sec to the vehicle to land. Another 2.4 km/sec is needed to return to Earth along a minimum energy orbit. Payload of Lunar Injection Stage The exhaust velocity in vacuum of an RL-10 engine with high expansion ratio is 4.3 km/sec. So, we have Lunar Injection 1-1/exp(Vf/Ve) = 1- 1/exp(3.5/4.3) = 0.5569 = 55.69% propellant So, this means that 5.68 metric tons of propellant carried to orbit aboard a single flight is capable of carrying an added 4.51 metric tons. This is enough to carry an 'open cockpit' lunar lander designed for the Gemini Program which massed 3.3 metric tons 'wet'. http://www.astronautix.com/craft/gemnilor.htm Lunar landing and take off would require a 4.8 km/sec delta vee, so require 1-1/exp(4.8/4.3)=0.6725 = 67.25% propellant With a total mass budget of 4.51 metric tons this leaves 1.72 metric tons of usable payload after subtracting 2.79 metric tons of propellant. Hydrogen and oxygen boil-off would be used to produce electricity and water during the flight. It is also used to produce oxygen. Carbon dioxide and odors re absorbed by reacting with hydrogen to produce methane and more water. Methane and excess water is evaporated to cool the spacecraft. 160 kg of propellant, along with another 140 kg of consumables, largely freeze dried foods reconstituted with hot water made from the fuel cells on board, are required for a 20 day flight for 3 people. The flight time includes 4 days flight out from Earth, 4 days flight back from the Moon, and 10 day stay on the moon, with 2 day margin. http://www.scribd.com/doc/40623446/Disk-Moonship-2 An unmanned version of this lunar module is loaded with only 2.52 metric tons of propellant, and 2.00 metric tons of usable load that is left on the moon permanently. 1.93 metric tons of propellant are burned to land the vehicle. The 2.00 metric tons are deposited. The remaining 0.59 metric tons of propellant are burned to lift the empty lunar lander back to Earth. So, two of these fully reusable spaceships are launched. One to place a lunar injection stage on orbit. One to place the lunar lander/ return stage on orbit. A crew of 3 enter the lunar lander/return stage and separates from the orbiter. The lunar lander/return stage docks with the lunar injection stage, and both depart for the moon, while the two orbiters return to Earth. After translunar injection, the two stages separate. The lunar injection stage loops around the back side of the moon, and returns to Earth. The Lunar Injection re-enters the Earth's atmosphere, and glides to a landing at an airport. There it is equipped with a strap on jet engine with jet fuel supply, and flown back to the launch center. The lunar lander carries out a direct descent to the lunar surface 4 days after departing Earth orbit. The crew of 3 spend 10 days on the moon. They then depart back to Earth - returning to Earth in 4 days - 18 days after launch. The lunar lander re-enters the Earth's atmosphere and glides to a landing at an airport. There it is equipped with a strap on jet engine with jet fuel supply, and flown back to the launch center. All parts are recovered and reused. An unmanned freighter flight carries 2.00 metric tons to the lunar surface one-way with automatic return of the vehicle. http://www.astronautix.com/project/horizon.htm http://www.scribd.com/doc/19766955/Lunar-Base-Concepts Extending the stay of astronauts to 60 days from 20 - consumes 0.90 metric ton of this payload. Another 1.10 metric ton is used for inflatable habitat and associated hardware. http://grin.hq.nasa.gov/IMAGES/MEDIU...2003-00106.jpg http://en.wikipedia.org/wiki/Inflatable_space_habitat The long-duration space suit life support hardware plugs into the grounded inflatable space station - to provide long term life support using the consumables on board the station. http://en.wikipedia.org/wiki/Space_activity_suit This entire system - a fleet of six launchers, and three trans-lunar injection stages, along with two manned landers and one unmanned freighter lander, along with a dozen payloads for the moon - provide continuous presence for nine people with a crew change of 3 every month for a total of $12 billion, and another $8 billion every 10 years to maintain operations there. The fleet of six launcher ships 18 flights to the moon per year along with 34 commercial flights per year. At $10 million per ton, each flight charges $56 million - and earns $50 million per flight, earning $1,700 million per year. After cost of lunar operations, an added $900 million per year is earned - providing 7.5% return on the $12 billion investment. 84 people per year visit the moon in this scenario. 28 are professional crew. 28 are scientists chosen from around the world. 28 are tourists who pay $20 million each. This earns an added $560 million per yer in sales, which cover the insurance and other costs associated with maintaining a higher service standard for all. The $900 million per year supports an additional $20 billion in debt. This is enough to build a larger launcher and larger payloads. http://www.scribd.com/doc/30943696/ETDHLRLV http://www.scribd.com/doc/31261680/Etdhlrlv-Addendum http://www.scribd.com/doc/35439593/S...-Satellite-GEO Which allow the operation to earn more money creating a global wireless hotspot along with a global wireless power network. Which lead to more advanced systems. |
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