# US spy satellite re-entry

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

1. ### kmguruStaff Member

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Even if the technology is old, how it is used should be kept secret...that is where you gain or lose your advantages. Remember the terrorists hitting the WTC. It is the strategy that surprised everyone except a few no name people.

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3. ### draqonBannedBanned

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the no name people in Pentagon.

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5. ### D HSome other guyValued Senior Member

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I took umbrage to the headline because a lot of people do not understand the concept of orbits. When we shoot a plane down it falls directly because of the explosion. The plane lost its ability to propel itself through the atmosphere and lost the mechanisms that keep it from falling. Satellites don't work that way.

I did answer your main question (why are they doing this??) after my brief lapse into semantics.

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7. ### draqonBannedBanned

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DH hello....in time everything in orbit of Earth will fall. In 100 years or so that debris will fall to Earth.

In fact thats the reason ISS goes through Apogee and Perigee...the boosters keep it accelerating up and gravity down

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Last edited: Feb 14, 2008
8. ### Echo3RomeoOne man wolfpackRegistered Senior Member

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Good show regardless.

9. ### D HSome other guyValued Senior Member

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Satellites in geosynchronous orbit will not fall to the Earth, period. For satellites in the exosphere, the time frame is in the millions of years or longer.

The problem I have with the phrase "shoot it down" is that many people have the misconception that satellites have to have some sort of powered flight to stay in their orbits. Popular fiction like Star Trek doesn't help, where the Enterprise's orbit decays rapidly as soon as the ship loses its engines.

10. ### draqonBannedBanned

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And why would it be in geosynchronous orbit? the speed will not be matching the needed one...since the thing has been destroyed some of the particles will be slower and some faster than the original satellite velocity. And the velocity direction of these particles would be different, so no geosynchronous orbit for either of them.

11. ### draqonBannedBanned

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DH answer me this...is ISS in geosynchronous orbit?

12. ### D HSome other guyValued Senior Member

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Dragon: you said "EVERYTHING" in orbit will fall. The ISS is but one of many orbiting bodies.

13. ### blobranaRegistered Senior Member

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i would generally agree.
Depending on the missile explosion, i expect many pieces will be shot into dangerous orbits.
It only takes a bolt to totally destroy a commercial satellite.

indeed, but i have a rough idea.
The reason that the military secrets aspect is, i feel, overrated is because spy satellites are deorbited every year. And people know exactly where they have been deorbited - A sonar seabed search would reveal all the parts.
The military were quite happy about it crashing uncontrollably before - until they remembered and realised the fuel tanks were full and would survive re-entry.

indeed.
The military seems to thinks that the danger from extra space junk is out weighted by the danger from the Hydrazine reaching the ground. As i mentioned before the titanium hydrazine fuel tanks are basically full, and would likely survive the re-entry.

14. ### cosmictravelerBe kind to yourself always.Valued Senior Member

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Couldn't the space shuttle grab onto it and put it inside of its cargo hold? I know there's ample room for it there. :shrug:

15. ### AsguardKiss my dark sideValued Senior Member

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that reminds me of that movie, space cowboys

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16. ### blobranaRegistered Senior Member

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Hum,
i wouldn't want to be in the Atlantis shuttle if the military decide to stupidly explode the satellite before the shuttle lands.

17. ### D HSome other guyValued Senior Member

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They didn't remember that. The military's initial reaction was "Yawn. It will burn up on reentry." Apparently it was NASA who told the military of the heightened risk resulting from orbiting unpowered for a year. From http://www.msnbc.msn.com/id/23172469/:
NASA Administrator Michael Griffin sketched out a different scenario, however, during Thursday's news conference with Gen. James Cartwright, the vice chairman of the Joint Chiefs of Staff. Griffin said NASA experts calculated that the hydrazine was frozen solid due to the satellite’s yearlong drift through the cold of space. The tank, with its half-ton ice core of hydrazine, would thus become one of the most perfect re-entry vehicles ever to fall back to Earth.

Griffin explained that the contents of the tank could turn to slush during the fall, but would very likely survive and leak toxic gas over the crash site. Another expert told msnbc.com privately that the solid ice would provide structural support against the 20 to 25 G’s of deceleration experienced by the satellite during re-entry.

18. ### blobranaRegistered Senior Member

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Hum,
since the interception missile is a kinetic weapon, i wonder how resilient that frozen fuel tank is....

19. ### blobranaRegistered Senior Member

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Hum,
it could be speculated that behind the scenes the Russians, Chinese or various other nations have been very vocal about the satellite; and that as a result of which, orbital information was leaked by the US department of defence (DoD).
And , it would also explain why the missile interception plan was made public. It could be seen as a political snub. As a bonus for the DoD, the interception missile system can be tested; but as kmguru said “Even if the technology is old, how it is used should be kept secret.”: We will now see how advanced the interception missile system really is.

Either way, i suspect the other nations, nor the DoD, aren't happy.

20. ### cosmictravelerBe kind to yourself always.Valued Senior Member

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When the Chinese blew up their satellite they never told anyone. That satellite was in a high orbit when it was destroyed leaving millions of pieces of debris in high orbit that could hit other satellites very easily. Those pieces of debris won't return to earth for over 20 years so everyone will be in danger now where that satellite was destroyed! Why wasn't anything ever said about that disaster???:shrug:

21. ### draqonBannedBanned

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1) helllo...its a spy satellite

2) it looks like someone learned of this spy US satellite and the info got to the public

22. ### blobranaRegistered Senior Member

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There was a huge outcry about the Chinese anti-satellite test .

Feng Yun 1 was orbiting more than 500 miles in space, and when the Feng Yun exploded, thousands of shards shot off in every direction. Today, the debris field extends from 125 miles above the surface of Earth to 2,500 miles. It has been calculated that it will take a century for all the pieces to fall out of orbit.
This proposed US missile test will probably create just as much debris but most of it will only last one or two orbits. The ISS hopefully orbits just outside of the resulting debris cloud.

There is good reason to believe that the orbital information was leaked on purpose by the US department of defence. The information only appeared after the Russians complained about the US secrecy about the orbital data. At the time there were rumours that it carried radioactive batteries (the satellite was observed to have no solar arrays. However, It was learned from the DoD that the satellite failed before it could deploy them.)

But generally, the details and capabilities of the satellite are educated guesswork.

23. ### PeteIt's not rocket surgeryRegistered Senior Member

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Apparently they're going to try for a direct hit on the fuel tank.
I wonder how visually impressive the strike will be from the ground?