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Soyuz TMA-11 Comes Home, More or Less...



 
 
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  #11  
Old April 20th 08, 08:10 AM posted to sci.space.history
Dale Carlson
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Default 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  
Old April 20th 08, 08:37 AM posted to sci.space.history
Dale Carlson
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Default 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  
Old April 20th 08, 08:14 PM posted to sci.space.history
[email protected]
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Default 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 ?
  #14  
Old April 20th 08, 10:10 PM posted to sci.space.history
Fevric J Glandules[_2_]
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Default 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.
  #15  
Old April 21st 08, 12:24 AM posted to sci.space.history
[email protected]
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Default 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  
Old April 21st 08, 04:56 AM posted to sci.space.history
Pat Flannery
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Default 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
  #17  
Old April 21st 08, 05:14 AM posted to sci.space.history
Pat Flannery
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Default 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
  #18  
Old April 21st 08, 08:07 AM posted to sci.space.history
Pat Flannery
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Default 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
  #19  
Old April 21st 08, 08:54 PM posted to sci.space.history
Alfred S. Dert[_2_]
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Default 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  
Old April 21st 08, 09:55 PM posted to sci.space.history
Bash
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Default 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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