# US spy satellite re-entry

Discussion in 'Astronomy, Exobiology, & Cosmology' started by blobrana, Jan 26, 2008.

1. ### scotlandRegistered Member

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2
Possible launch location of spy sattilite in question..

astronomy.magnify.net/item/YFQLYHKL0GTCF5LV
astronomy.magnify.net/item/HNGVFG0CFMC7KWLP

3. ### blobranaRegistered Senior Member

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False Information Deleted (FID)

Last edited: Jan 31, 2008

5. ### blobranaRegistered Senior Member

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Whoops
forget what i said

i plugged in the wrong data.... Yes the satellite was passing at 8:23 UT.

congratulations you spotted the satellite.

The two streamers? don't know it could be fuel

7. ### blobranaRegistered Senior Member

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@scotland
Here is a predicted satellite position at 6:50 UT, Feb 1st, 2008.

Expand (55kb, 630 x 390)

Magnitude 4.8 v
Orbit 273 x 271 km,
inc 58.5 deg.

(There is another chance to spot it at around 8:15 UT.)

8. ### iceauraValued Senior Member

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30,994
Blobrana:

stupid question I can't answer for myself: In those pictures, what are the other two tracks - the ones that don't meet - representing?

9. ### blobranaRegistered Senior Member

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Hi,
the other two tracks are just the same satellite track that is wrapped around the world.

The satellite orbits in about 89 minutes; but for clarity the map just shows part of the ground track. The notches are spaced about a minute apart.

10. ### OrleanderOH JOY!!!!Valued Senior Member

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Anyone watch Dead Like Me? The satellite doesn't have a toilet on it does it?

11. ### blobranaRegistered Senior Member

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Hum,
Probably not;
Although the satellite is large every part of it would be reviewed before launch to cut down on weight.
As the satellite is fully automated, the essentials such as toilets would be removed.

12. ### OrleanderOH JOY!!!!Valued Senior Member

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good, then I'm not worried

13. ### LaikaSpace BitchRegistered Senior Member

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Out of curiosity, how big is a small armoured bus compared to, say, a small unarmoured bus?

14. ### blobranaRegistered Senior Member

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Hum,
the same size;
but it will be important as it starts to break up and burn up.

(You remember what happened to the unarmoured asteroid that was heading straight for Springfield?)

15. ### OrleanderOH JOY!!!!Valued Senior Member

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so now they are gonna use missles and shoot it down??? Why??

US Plans To Shoot Down Falling Military Spy Satellite

http://www.ktvu.com/news/15175640/detail.html

WASHINGTON -- The Pentagon is planning to shoot down a broken spy satellite expected to hit the Earth in early March, The Associated Press has learned.

U.S. officials said Thursday that the option preferred by the Bush administration will be to fire a missile from a U.S. Navy cruiser, and shoot down the satellite before it enters Earth's atmosphere.

The officials spoke on condition of anonymity because the options will not be publicly discussed until a later Pentagon briefing.

The disabled satellite is expected to hit the Earth the first week of March. Officials said the Navy would likely shoot it down before then, using a special missile modified for the task.

Other details about the missile and the targeting were not immediately available. But the decision involves several U.S. agencies, including the National Security Agency, the Department of Homeland Defense and the State Department.....

16. ### Avatarsmoking revolverValued Senior Member

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19,083
Probably it's either dangerous to whomever that satellite is going to fall on the head, or there's some state secrets they don't want to fall (ha!) in the wrong hands.
Either way it seems that not all of it is going to burn up.

17. ### D HSome other guyValued Senior Member

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The headline is a bit misleading in the sense that the military is not going to "shoot it down". They are simply going to shoot it. It will fall down all by itself.

So why do this? They don't want the satellite to hit the ground. A largely intact sattelite might well do some damage if it lands in the wrong place. It could also do a lot of damage to the military if the pieces land in the wrong hands (i.e., people who can decipher the military secrets embodied in the satellite).

Blowing the satellite up will do two things. First, it will blow it up (duh). The explosion itself may render unreadable the avionics and sensors that the military wants to keep out of enemy hands. Second, the fragments will burn up in the upper atmosphere. Big things (be it asteroids or satellites) have a much, much better chance of making it all the way to the ground than do little things. Aerodynamic friction is proportional to surface area and inversely proportional to mass.

18. ### blobranaRegistered Senior Member

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Blowing it up will create a lot of spacejunk; some of which will be shot up into higher orbits.
As i remarked earlier, most of the parts that will survive the re-entry will not be affected by the explosion. The scatter field will just be made larger.
As for sensitive military secrets; i feel that aspect is overrated.

There real danger, it seems, is from the hydrazine onboard.
The explosion will scatter the toxic propellant into the very upper atmosphere.

Another perhaps political viewpoint, is that it will test the navy missile system...

19. ### Echo3RomeoOne man wolfpackRegistered Senior Member

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The "space junk" aspect is irrelevant here. The satellite is in a rapidly decaying orbit and is already experiencing drag from the upper atmosphere. Component debris will fall in and burn up just like the bird would, only the fragments will have more surface area than the intact satellite, so they'll burn up faster. The chances of anything making it to earth will be greatly reduced, depending on how it breaks apart on intercept.

Military secrets overrated? I'm going to take a wild guess that you've never held a security clearance.

I'm not sure why the propellant should be a concern. There's not much of it, and there's a lot of room up there. What difference does it make?

20. ### D HSome other guyValued Senior Member

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Not too much higher. The vehicle is moving at 17,600 miles per hour. A few chunks might get an a boost of a few hundred mph. This will only change apogee; the perigee will remain unchanged. In other words, parts of the orbit will remain deep in the exoatmosphere. Those chunks will have a high surface area-to-mass ratio, so they won't survive as space junk for long.
Debris from a reentering satellite does not always make it to the surface. A lot of it just burns up in the atmosphere. When satellite debris does hit the Earth, it is usually because the satellite didn't break up until it had plunged through a large part of the atmosphere. If the breakup occurs in the dense part of the atmosphere, the resulting debris will quickly slow down without overheating. If the breakup occurs high in the atmosphere there is a much smaller chance of debris reaching the Earth. The greatest heating occurs in the upper atmosphere where the atmosphere is still very thin and the vehicle (or its parts) still have near orbital velocity. This satellite will break up even higher than that, before entry interface.
You don't know what capabilities this satellite has onboard. Hint: They're secret, probably TS. Learning by means of reverse engineering is fast, cheap, and effective. Destroying the satellite eliminates that learning tool.

Where it will burn up.

A lot of the hydrazine will burn with the explosion. Hydrazine is a monopropellant (and a bipropellant as well; one of very few in this category). It does not take much energy to set hydrazine off. Contact with platinum will do it, and so will a boost of energy from an explosion.

Bingo. This is a chance to use their fancy ASAT toys on a live target moving at 17,600 mph.

Last edited: Feb 14, 2008
21. ### OrleanderOH JOY!!!!Valued Senior Member

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LMFAO!! You have got to be kidding me. :roflmao:

Ah, hair splitters. <sigh>

22. ### kmguruStaff Member

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IMHO, USA is itching to test their own version of the new fangled sattelite killers.

1. Missile
2. High energy Laser
3. High energy particle gun

Could be Northrup or one of the contractors want to sell something and this is a good way to test it before Uncle Sam will plunk down several Billion Dollars for the new system.

23. ### draqonBannedBanned

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35,006
yes, this satellite will be destroyed by the USA missile...just like China destroyed one of their falling satellites not long ago