# US spy satellite re-entry

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

1. ### Echo3RomeoOne man wolfpackRegistered Senior Member

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The biggest difference, from what I've read, was rewriting the guidance software to discriminate the satellite against the backdrop of space. The SM-3 uses a monochromatic IR seeker to track TBM RVs, which are heated by friction and ablation against the upper reaches of the atmosphere. The satellite was much closer to ambient temperature at the time of intercept.

As far as success rates go, AEGIS BMD does pretty well. Second to Patriot, it is the most mature BMD system in our arsenal. It hasn't suffered the same systems integration issues that Ground-Based Intercept has (the land-based interceptors in California and Alaska). I think the Navy is up to a dozen intercepts now during testing. The most recent ones have involved Japanese warships providing telemetry to the launch ship, and the most recent test had a JMSDF ship firing the SM-3 from its VLS launcher.

3. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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Lets hope so; however, the Chinese have a reconance craft in orbit about the moon, so if they were crazy, they could take out Washington DC. (They might think a "decapitation strike" might work as firing our ABMs does require code release.)

Last edited by a moderator: Feb 21, 2008

5. ### BenTheManDr. of Physics, Prof. of LoveValued Senior Member

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So why does everybody say that BMD is such a waste of money? Aside from the fact that no one would be stupid enough to launch an ICBM at America anytime soon and that the money is probably better spent elsewhere, it seems at least technologically possible, especially based on this result.

7. ### BenTheManDr. of Physics, Prof. of LoveValued Senior Member

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This is what I figured---it couldn't be too much greater than escape velocity.

8. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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I said that about the Teller inspired version in space Reagan wanted, (X-ray laser etc.) but what APL has designed (but not built) makes a lot of sense to me.

9. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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Sure it could. - It just depends on the direction and how long you thrust. You don't need to even follow an elipse as I suggested, but think that may be useful plan. -I.e. if you did not hit the earth/ target, the next apogee would be much higher still but you would need to avoid escape by thrusting back along the elipse towards Earth. - Don't use the energy you pumped into the bird to coast up a gravitational hill.

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10. ### Echo3RomeoOne man wolfpackRegistered Senior Member

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Personally, I think Reagan's SDI biased a lot of people against the concept of BMD in general because of how ambitious it was. The stuff being worked on nowadays isn't based on fantastic theoretical ideas, like constellations of X-ray laser satellites and orbiting particle beam weapons, but practical and deployable technologies, like the system used against this satellite, THAAD, Patriot, MTHEL/Skyguard, the Airborne Laser, etc.

11. ### kmguruStaff Member

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I think there were several reasons for a mad campaign to discredit Regan's SDI program. The peace actvists went nuts over it like they did in anti-nuclear rallies during early seventies. There was a russian guy who became a front for such opposition. At the time MTHEL was in development stage and everyone pooh-poohed it. There is also politics and competition within the military contractors. I was told, one general borrowed a ULF communication idea and gave it to the competitor....

When Biology scientists say, SDI does not work - they usually do not understand the technology. I have not seen any smart Electrical/Control Engineer that was against it then. The problem with particle weapon was the charge and discharge control - that has been solved long ago.

12. ### AsguardKiss my dark sideValued Senior Member

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Firstly satilets tend NOT to have counter mesures which ICBM DO have and all of you seem to be ignoring that fact.

Secondly to billy, of course i was serious, why is it so hard for countries to co-operate, I didnt realise the US had the tech to do the job, they did so good on them. I KNEW china did because it blew a sat out of the sky so they could have done it if they needed to. Futher more if countries can co operate to build the ISS then they could have co operated to bring a sat down. Risking lives because your to gutless to ask for help is an idiotic proersition

13. ### Echo3RomeoOne man wolfpackRegistered Senior Member

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Which ICBMs have countermeasures and what sort of countermeasures are they?

14. ### D HSome other guyValued Senior Member

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ICBMs do not currently carry countermeasures. If some country did develop a viable ABM program, adding countermeasures such as fake warheads and other decoys would be a snap. That is why the ultimate goal of any ABM program is to hit the target missile during the boost phase.

15. ### AsguardKiss my dark sideValued Senior Member

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I dont know, im just going off the news reports that the US millatry has made on the Missile defence shild. That the missiles cant distinguash between the "real" missile and the counter mesures

My training isnt in millatry weaponry its in the medical field

16. ### BenTheManDr. of Physics, Prof. of LoveValued Senior Member

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So what's the problem with shooting more missiles towards the warheads?

I get the feeling that people who don't believe that BDM can work are also people who would rather spend the money on other things.

17. ### Echo3RomeoOne man wolfpackRegistered Senior Member

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The simplest answer to the decoy question is that all the upper-tier BMD systems (GBI, AEGIS, THAAD) use dual mode guidance during the terminal phase of intercept. The interceptor carries an onboard IR telescope, while the ground-based radar has a short wavelength and a super high resolution. Between the two, radar decoys like chaff fail to spoof the IR sensor, while at the same time the radar sees through mylar balloons (the oft-mentioned IR decoys). Add a battle management suite that can conflate and process all that information lightning fast, as well as multiple interceptors allocated to each individual target, and the kill probability climbs up pretty high.

18. ### AsguardKiss my dark sideValued Senior Member

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People im not going to debate what contermesures there are on an ICBM or wether its a good idea or not. I was just pointing out to the poster who said "if we can hit a sat why cant we hit a missle" that there are differences between a sat that goes around in basically a straight line and you can predict where it is and wont shoot things back at your missile to a ICBM that CAN theoretically do all those things

19. ### BenTheManDr. of Physics, Prof. of LoveValued Senior Member

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But ballistic'' means that you CAN predict where it's going to go. I have two classes full of undergraduate engineers who can solve the equations.

20. ### D HSome other guyValued Senior Member

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Like the satellite that was just hit, an ICBM goes "basically in a straight line". The "B" in ICBM means "ballistic". They do not maneuver. They do not shoot back. Countermeasures are passive devices that can only confuse a rather stupid attacker (e.g. an ASAT weapon). If an attacker can see through the subterfuge of the countermeasures, game over.

21. ### kmguruStaff Member

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I thought an Aegis class missile was used to kill the satellite and not an ICBM!

22. ### draqonBannedBanned

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modified SM-3

23. ### D HSome other guyValued Senior Member

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No body ever said an ICBM was used. We were talking about hitting ICBMs in lieu of wayward satellites.