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Soyuz TMA-11 Comes Home, More or Less...
On Sun, 20 Apr 2008 01:23:21 -0500, Pat Flannery
wrote: In calm wind conditions, the chute could come down directly over the capsule, and be ignited by a fire started by the landing rockets. Chute jettison is manual, and normally occurs a few seconds after landing. If the crew was stunned by the force of impact or the high G's of reentry, they may have delayed the jettison of the chute. (I've got a photo of a landed Soyuz that got dragged quite a ways through the snow before the crew could manage to jettison the chute.) But that's odd...if they did land in a bog, the landing motors shouldn't have started a fire. Generally, a hard landing means the landing motors didn't fire, so no burning chute in that situation either. In its belated coverage, the NY Times includes a photo. http://www.nytimes.com/2008/04/20/world/europe/20space.html Appears to be not a bog, but rather a grassy steppe. The capsule doesn't appear to be particularly embedded in the ground. Burned grass is evident to the left (nose end) of the capsule in the photo. Whatever caused the 20 minute delay, that would explain why the landing has been described as an "overshoot", as I assume the steeper trajectory of a ballistic course would result in the opposite. Reporting the obvious, Dale |
#12
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Soyuz TMA-11 Comes Home, More or Less...
To follow up on my own post- at the time the photo in the NY Times
was taken, there appeared to be a pretty strong wind from right to left (in the photo), as evidenced by the blowing tails of the white coats a couple of guys are wearing. The capsule is also tipped in that direction, probably by the parachute. And if the landing rockets set the grass on fire, it would have spread in that direction, away from the capsule, as shown in the photo, and into the settling 'chute. Thus, no need for a burning parachute on descent. The heatshield is gone, so the landing rockets likely fired. Seems like a simple enough explanation to me... Dr. Quincy, M.E. |
#13
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Soyuz TMA-11 Comes Home, More or Less...
On Apr 20, 7:07*am, Pat Flannery wrote:
wrote: Tonight NBC news had some locals who had seen it come down and one said "the parachute was on fire". *Discounting any possible confusion with "thump down"this is a whole other story. * Could ballastic reentry have done this (if true)? *Sort of reminds me of Komarov's reentry...................Doc Soyuz 5 suffered parachute heat damage when it started reentering pointy-end first after the service module failed to separate. In Komarov's case the parachutes barely got out of the storage containers due to a foul-up during construction. If the chute was damaged or was smoldering during landing, that would suggest either a problem with the pyrotechnic deployment system or something very abnormal during reentry that exposed the forward body of the spacecraft to reentry heating. damaging the hatches over the main and reserve chutes, such as tumbling or wobbling of some sort. During a ballistic reentry the capsule is put into a slow roll for stability and even heating of the heat shield and exterior. If it wasn't put into that roll, it might start wobbling on the way down. Interesting facet of the story is that for some reason the landing was about 20 minutes later than expected:http://www.wtte28.com/template/inews...tional/20d664c... That suggests a late or not completely successful retro burn, as the ballistic reentry would get you down faster than the normal one. What's really odd is a retro burn 20 minutes late would put you _way_ off course, in fact it might put you down somewhere in the Pacific Ocean. If there is a problem with the retro engine (they have deleted the twin nozzle back-up engine on the TM and TMA IIRC) SOP says to do a series of orbits till in the intended reentry area again, not to fire the retro late, as landing in rough territory can be fatal.... you might end up rolling down a mountain like Soyuz 18-1, or hanging in a tree with hungry wolves around the spacecraft, like Voskhod 2 (one notes that those wolves get a little larger, closer, and more hungry every time Leonov tells that story. Soon, I expect them to be described as werewolves.) ;-) Another possibility would be a complete failure of the retro engine and a reentry burn done via the RCS engines for braking. That would be hard to do in a way that would put you down in a predicted spot. I think a lot of interesting things about this mission's end will come out in the next few days. Pat Just wondered,if this was the most ofcourse "landing" since Scott Carpenter,got rather busy in 1962 ? |
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Soyuz TMA-11 Comes Home, More or Less...
On Sun, 20 Apr 2008 00:47:37 -0500, Pat Flannery wrote:
The Russians consider a survivable high-G reentry much preferable to a abnormal one that results in the destruction of the capsule. I'm with the Russians on this one. -- One way ticket from Mornington Crescent to Tannhauser Gate please. |
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Soyuz TMA-11 Comes Home, More or Less...
On Apr 20, 2:10 pm, Fevric J Glandules wrote:
On Sun, 20 Apr 2008 00:47:37 -0500, Pat Flannery wrote: The Russians consider a survivable high-G reentry much preferable to a abnormal one that results in the destruction of the capsule. I'm with the Russians on this one. -- One way ticket from Mornington Crescent to Tannhauser Gate please. Me too, but it must be a punishing ride for a crew that has spent months in zero gee to endure ten gees.... crammed with your ankles into your rear end in those cramped seat liners. |
#16
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Soyuz TMA-11 Comes Home, More or Less...
Dale Carlson wrote: Whatever caused the 20 minute delay, that would explain why the landing has been described as an "overshoot", as I assume the steeper trajectory of a ballistic course would result in the opposite. That can't be right; a twenty minute delay means the capsule was floating around for twenty minutes under its descent under its parachute, and to get that to happen it would need to get sucked up in some sort of giant thermal updraft like would be caused by a thunderstorm. I dug out all my stuff on Soyuz reentry details last night and the amount of deviation from the normal landing target is right on the nose for a ballistic reentry (450 km), but that's a undershoot, not a overshoot. To get a overshoot of that magnitude, the capsule would have had to do some sort of a aerodynamic skip-type maneuver during reentry, if it had a nominal retro burn. A 20 minute delay in retrofire means you are going to come down around 1/4 of the Earth's circumference away from where you were supposed to have landed. A short or late retro burn could make you overshoot the landing site, but coming down with a 450 km overshoot with a ballistic reentry means you need a normal reentry landing point that is 900 km off from where it was intended to be. That would explain why the crew "chose" a ballistic reentry though... it would allow them to come down far short of where a normal lifting reentry would have put them. That still isn't 20 minutes difference though. Pat |
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Soyuz TMA-11 Comes Home, More or Less...
Dale Carlson wrote: Thus, no need for a burning parachute on descent. The heatshield is gone, so the landing rockets likely fired. Soyuz TMA has both a primary and secondary set of landing rockets on its base; I've always wondered what would happen if the first set firing reflected its exhaust off of the ground, and ignited the second set. In the photo there appears to be a large burn mark to the left of the picture, so I assume that's where it originally touched down. That doesn't agree with the side the top of the capsule is facing if the parachute dragged it around due to the direction of the wind shown in the photo, or its final position. When I was writing that earlier posting, I realized you could be in a world of hurt if the returning Soyuz capsule ever did descend into a thunderstorm due to something doing off-kilter during reentry. If the updrafts did pull the capsule upwards into the storm, its parachute could become so covered with ice that its weight would cause the capsule to fall out of the sky like a rock. This may be one reason there is a automatic primary chute jettison/back-up chute deploy built into the spacecraft if the onboard systems indicate too rapid of a descent rate. Pat |
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Soyuz TMA-11 Comes Home, More or Less...
wrote: Just wondered,if this was the most ofcourse "landing" since Scott Carpenter,got rather busy in 1962 ? That's got to be the record-holder outside of "Wrong-Way Corrigan": http://en.wikipedia.org/wiki/Douglas_Corrigan .....Irish-American hero. Aye, lad; that's the very spirit of the Blessed Mother Isle! I baptize my tongue with a drop of the fine old poteen, so as to better and more eloquently sing your praises! :-D Stories still vary as to whether the Soyuz came down in the USSR, or slightly over the border into China. The paraphrased communications from the Soyuz to mission control were supposed to be something also: "We are going out of control!" "We indicate your ascent profile is normal." "We are going end-over-end!" "Are you sure?" "**** you!" :-D They did set the all-time record for deceleration and survived manned reentry..._21.3_ G's: http://en.wikipedia.org/wiki/Soyuz_18a The Soyuz may have a history of doing odd and dangerous things, but by God, is that one tough little SOB. It's going to do its damnedest to get you down alive, even it you end up rolling down a mountainside like in this case, or getting most of your front teeth knocked out, like on Soyuz 5: http://en.wikipedia.org/wiki/Soyuz_5 Boy, I wish the Shuttle was that robust. "Columbia belly-lands on Texas cattle ranch; 'May need major repairs' NASA states. Crew 'shaken and bruised'." Pat |
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Soyuz TMA-11 Comes Home, More or Less...
Pat Flannery schrieb:
The Soyuz may have a history of doing odd and dangerous things, but by God, is that one tough little SOB. It's going to do its damnedest to get you down alive, even it you end up rolling down a mountainside like in this case, or getting most of your front teeth knocked out, like on Soyuz 5: http://en.wikipedia.org/wiki/Soyuz_5 Or acting as submarine: http://en.wikipedia.org/wiki/Soyuz_23 |
#20
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Soyuz TMA-11 Comes Home, More or Less...
I liked the comment by the official blaming the crew- saying that they
overshot because they had selected a ballistic reentry without telling mission control. What a bunch of irresponsible thrillseekers Dale If they'd really wanted to thrill seek they should have jumped out and parachuted in as soon as the capsule had slowed beneath sonic speed. Cowabunga dude! ;-) |
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