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02-19-2008, 05:01 PM
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#41
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Moderator Emeritus
Join Date: Dec 2002
Location: Oahu
Posts: 26,860
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Quote:
Originally Posted by REWahoo
Looks like they moved up the shot to Wednesday night. Itchy trigger finger?
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I did the time conversion wrong*, that NOTAM is for Wednesday around the time when the satellite is expected to be overhead (5:30 PM HST).
Rumor is the shot will be from PMRF (where the instrumentation is) rather than off Maui. But I'll try to look both ways.
I think at least one flag officer is afraid that the chain of command will change their mind before the ordnance is released...
In an instance of supreme irony, my spouse (a Navy Reserve emergency-planning officer) has been asked to get ready for a day or two of duty when the Army activates their DCO to watch the Navy splatter hydrazine all over the islands troposphere.
*Sheesh, I can't even frickin' convert from ZULU to HST anymore. Well, that settles it, I can't ever go back to work again.
__________________
*
Co-author (with my daughter) of “Raising Your Money-Savvy Family For Next Generation Financial Independence.”
Author of the book written on E-R.org: "The Military Guide to Financial Independence and Retirement."
I don't spend much time here— please send a PM.
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02-19-2008, 05:13 PM
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#42
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Give me a museum and I'll fill it. (Picasso) Give me a forum ...
Join Date: Jun 2002
Location: Texas: No Country for Old Men
Posts: 50,021
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Quote:
Originally Posted by Nords
...I can't ever go back to work again.
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About time you figured that out - we've know it for years....
__________________
Numbers is hard
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02-20-2008, 09:09 PM
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#43
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Give me a museum and I'll fill it. (Picasso) Give me a forum ...
Join Date: Jun 2002
Location: Texas: No Country for Old Men
Posts: 50,021
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__________________
Numbers is hard
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02-20-2008, 10:16 PM
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#44
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Moderator Emeritus
Join Date: Dec 2002
Location: Oahu
Posts: 26,860
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I'll have to wait for the video-- I didn't see a thing. The weather was overcast around here and the missile might've already been above the cloud cover by the time it was over my horizon.
Spouse was on two-hour standby but cooler heads prevailed and the Army didn't want to waste the money decided not to call in Reservists to man the emergency-response command center. Or maybe they realized that the hydrazine tank was going to land on Texas, not Oahu.
As for LAKE ERIE, I'll bet the paint is already dry on the satellite silhouette added to the missile launcher! Whew, and good for them. I can't imagine having to knock down a target with SECDEF, VCJCS, and STRATCOM wandering around looking over my shoulder and offering helpful suggestions. Wonder if the CO gets a DMSM or a LOM for his end-of-tour award...
__________________
*
Co-author (with my daughter) of “Raising Your Money-Savvy Family For Next Generation Financial Independence.”
Author of the book written on E-R.org: "The Military Guide to Financial Independence and Retirement."
I don't spend much time here— please send a PM.
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02-20-2008, 11:47 PM
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#45
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Moderator Emeritus
Join Date: Feb 2005
Location: San Diego
Posts: 5,267
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Really happy for the crew of LAKE ERIE, I'm sure somebody is going to get an early look out of this one.
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02-21-2008, 05:45 AM
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#46
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Thinks s/he gets paid by the post
Join Date: Aug 2002
Posts: 1,322
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I'm sure the spacetrackers will be busy for a while mopping up the mess -- tracking and cataloging any pieces of junk that won't decay right away. "Sorry guys, all leave is canceled until further notice." I had to do that many years ago after some space breakups. Good shot Navy, but how about shooting at sea targets now?
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02-21-2008, 07:14 AM
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#47
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Dryer sheet aficionado
Join Date: Jan 2008
Posts: 42
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Some observations.
1. This FIA satellite was in low enough orbit that atmospheric drag will eventually bring down all the pieces. Anything having a non-round profile will have high coefficients of drag. So the pieces will come down.
2. Having 1000lbs of hydrazine indicates this was a fairly high mass object that did a lot of maneuvering about it's own CG during daily passes (augmenting it's CMG capability for quick target changes) and also the huge amount of hydrazine would allow it to be delta-v'd as required. Repositioning nodally or re-boosted after drag induced orbit decay.
I think our reason for shooting it down was first and foremost to ensure destruction of the encryption chips (Crypto keys) and hardened computers with the command authentication algorithms. Inside a massive spacecraft these might have survived re-entry.
But the hydrazine ruse then provided a great cover story to test our, newly proven (as of Wed) anti-sat capability.
Well done to the Navy. Good show.
http://www.nytimes.com/2007/11/11/wa...nted=all#step1
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02-21-2008, 08:55 AM
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#48
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Thinks s/he gets paid by the post
Join Date: Aug 2002
Posts: 1,322
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Quote:
Originally Posted by TBPu
Some observations.
1. This FIA satellite was in low enough orbit that atmospheric drag will eventually bring down all the pieces. Anything having a non-round profile will have high coefficients of drag. So the pieces will come down.
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First, you may be completely correct, hopefully you are -- we'll know in a few days what, if anything, is left. Second, I agree, the Navy did a good job. As much as I hate to admit it, the Navy does a better job at a lot of these things than the Air Force. But, they don't have as much time to play golf.
Now, as far as the pieces coming down, yes they will eventually come down but here is the potential problem, based on having been a spacetracker for several years when on active duty. It's about delta-v. When the collission happened it would most likely have been head-on. Most pieces coming off the satellite would receive a negative delta-v, in the direction opposite the collission vector, as what happens when two billiard balls strike. That's good, because the pieces are slowed down and they reenter even faster.
Some pieces will receive delta-v at other angles, though, and the problem would be with pieces that received positive delta-v. That can happen because you are striking a big object with a small object. At closing speed of 10 or more km/sec, parts of the big satellite would be ahead of the collision point when propelled forward by parts of the collision, whether physical particles or outgas explosions from the vaporized hydrazine.
Parts that get positive delta-v act as if they have been injected into a minimum energy (Hohmann) elliptical transfer orbit. Their previous position becomes a new perigee, and they go into an elliptical orbit with apogee at a higher altitude depending on the amount of delta v they received. I did some back of the envelope calculations, and figured a delta v of 3 km/sec, about 30% of the collision velocities, would be enough to transfer a piece into a 2000km apogee elliptical orbit. That piece would still come down to the lower orbit at perigee, where it would encounter the higher drags that you mentioned but, based on orbital models, they would have a lifetime of a year or more (orbital debris models are highly inaccurate, especially for elliptical orbits). And what makes it more of a problem is that an elliptical orbit of that nature intersects the LEO orbits of many other satellites, including the space station. Still, there's a lot of space out there, so the chances of a collision are small but nonzero.
Bottom line, I'm not disagreeing with what you said, in fact, you are probably correct. Just pointing out the uncertainties, and the fact that orbital debris is very hard to predict or track. The smaller the piece, the more unstable the orbit, and oftentimes we don't even know a piece of debris is there.
Now, having had to refresh some brain cells from long ago, I do not guarantee the above is completely correct. In fact, hope I got it wrong so I don't get recalled.
P.S. You may have a point with the cryptos, hadn't thought about that.
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02-21-2008, 09:24 AM
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#49
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Give me a museum and I'll fill it. (Picasso) Give me a forum ...
Join Date: Jul 2003
Location: Kansas City
Posts: 7,968
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Yes!
heh heh heh -
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02-21-2008, 09:36 AM
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#50
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Give me a museum and I'll fill it. (Picasso) Give me a forum ...
Join Date: Jun 2006
Posts: 12,880
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My questions:
1. I figured that the smaller pieces (football and smaller) would burn up as they reentered, but from your post, Soon, it sound like that's not true. What burns and what just gets hot?
2. Anyone know why the satellite failed in the first place? I've read power supply failure.
3. Was fixing it as part of a shuttle mission an option?
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02-21-2008, 10:32 AM
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#51
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Thinks s/he gets paid by the post
Join Date: Dec 2007
Posts: 4,764
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Hey China is asking we share the data...
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02-21-2008, 10:49 AM
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#52
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Thinks s/he gets paid by the post
Join Date: Aug 2002
Posts: 1,322
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Quote:
Originally Posted by TromboneAl
My questions:
1. I figured that the smaller pieces (football and smaller) would burn up as they reentered, but from your post, Soon, it sound like that's not true. What burns and what just gets hot?
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No, Al, that's not what I meant. You are right, all pieces will eventually reenter, and when they reenter they all get heated to several thousand degrees from atomospheric drag. Most pieces burn up completely during the 10-15 minutes of reentry at these temperatures. But if a piece is large enough, at least a part of it may survive to the ground. This has to do with its coefficient of drag, the material, its shape and orientation, etc.
What I was referring to is that some pieces may get "blown up" into a higher altitude, with less atmospheric drag. They will also eventually reenter and burn up, but it may take a year or more, instead of the hours or days it takes for those at lower altitude to reenter.
Fixing the satellite in a space shuttle mission was never an option for many reasons. Different orbits, no docking apparatus, etc.
As far as 2, if I knew, and if I told you I would then have to kill you
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02-21-2008, 12:08 PM
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#53
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Thinks s/he gets paid by the post
Join Date: Mar 2005
Posts: 2,603
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__________________
FIRE'd since 2005
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02-21-2008, 01:16 PM
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#54
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Moderator Emeritus
Join Date: Dec 2002
Location: Oahu
Posts: 26,860
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Quote:
Originally Posted by SoonToRetire
Good shot Navy, but how about shooting at sea targets now?
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Sorry, the submarine force had to sit this one out.
Quote:
Originally Posted by tryan
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Sure, why not? We invited PRC leadership to ride the U.S. carriers during a three-CVN exercise off Guam last year, and made sure that they got plenty of exposure to long-term high-tempo flight ops as well as night traps.
In other words we did our best to scare the crap out of them. Hopefully the missile video has been carefully edited (if that was even necessary) to produce the same effect. They'd hire George Lucas to do the editing & special effects if they thought it would help.
When spouse was guiding foreign VIPs during her COBRA GOLD Reserve duty, the PRC "officers" were always trying to surreptitiously snap cell-phone photos of command centers and computer displays. She duly reported that up the chain of command and the response was "Great, thanks,give 'em the best shots you can find, and tell them plenty of scary sea stories!" She didn't have to pay for a frosty beverage for the rest of the trip.
Somewhere a group of PRC intel analysts are trying to figure out why she and her submarine spouse are responsible for so many amazing achievements...
__________________
*
Co-author (with my daughter) of “Raising Your Money-Savvy Family For Next Generation Financial Independence.”
Author of the book written on E-R.org: "The Military Guide to Financial Independence and Retirement."
I don't spend much time here— please send a PM.
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