# US spy satellite re-entry

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

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

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How long does the boost phase last? I mean, given reasonable amounts of time to respond, is interception during the boost phase feasible?

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

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Probably not, if the reaction clock starts with "lift off." But it takes some weeks (usually) for the ICMB to set up for launch and spy satellites only have a relatively few locations on Earth to "keep and eye on." What completely changed this was the Polaris sub's ICBMs (and those of other nations with similar capacity) - Why the US Navy tries to know where all are at all times, and often has an attack sub making "shaddow" on them if they can.

5. ### D HSome other guyValued Senior Member

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Only 3 to 5 minutes. Nonetheless, intercepting during the boost phase is one goal of a layered approach. Googling "boost phase missile defense" gives 38,200 hits, several of which discuss means for achieving this goal.

7. ### SaquistBannedBanned

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Some one mentioned the Ageis missle boat...
I ask this question...how do missle cruisers defend against missle attack? Chaff, Phalanx canon, missle to missle... Which is more reliable?

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

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"Defense in Depth" - not a choice of defending weapons. It also depends on the number and type of US ships. Typically the carrier is at the center of the battle group. If a hostile force is in the area, the carriers planes will be in "chain-saw" mode -I.e. each in turn (or pairs) flying out to near their range limit and after their dwell they return for fuel, perhaps a new pilot, and a new one arrives to take up the outter guard posts. They may be able to shoot down a cruise missle, especially subsonic ones. As soon as an attacking cruise missle breaks the any ship's radar horizon an SM will launch to fly out at it from the periferal ship (hopefully an Aegis ship) on the side the attack is coming from. In recent years, the big radar picture has been fully intergrated - not just one ship's radar data view. (This is called "cooperative engagement" - APL developed that too.)

Without this ablility a large attack could exhaust the load out of missles availible in that periferial ship. - With cooperative engagement system, some of the missles defending ships under attack may come even from a ships on the other side of the carrier and be "handed off" to ship best positioned to help them engage the target. Typically there will be 3 or 4 opportunities to knock down the incoming older (subsonic) cruise missles, such as Chinese silkworms* etc., but modern supersonic Sea-skimmers like the French Exocet are may not be detected until closer (radar horizon is closer for sea skimmer) and as going faster, may only get one engagement opportunity with the Standard Missiles. then shorter range, cheaper (and I think faster) missiles, like the Nato Sea Sparrow, will try to shoot the incoming "leaker" (leaked thru the outer defense) down. If that too fails then the CIWS (close in weapon system) takes over. The CIWS is basicall atomomous - its radar track its own out-going bullets and the incoming threat and "merges" them. I.e. thousands of bullets make a "flying wall of steel" for the cruise missle to try to fly thru. There are electronic jaming efforts, perhaps heat decoys, during this entire time as the incoming cruise missle needs its radar and or IR system to know where its target ship is. I do not think Chaff is ever used - the ships radar cross section is just too big to decoy with chaff, and its centrod is not high above the sea.

To evaluate the performance of thisw defense in depth one used Monte-Carlo analysis. I.e. the subsequent battle -every thing from which ship is guiding and which is engaging etc. changes completely with the results of the very first engagement (a kill or a leaker) Thus you fight the battle several hundred times in Monte-Carlo simulation and average the results to evaluate all your options for defense of the battle group. There are at least two subs under the carrier battle group to keep enemy subs away. Defense in depth would be impossible if cruse missles were to suddenlt pop up out of the sea a half mile from the ship. There are some slow cruise missle that do the reverse - I.e. if they can get close enough (not possible against a battle group but a sea skimmer might have slight chance against an isolated ship) they dive into the water and become a torpedo, and then no longer a radar object. Noise decoys and shallow depth charges are then used.

The USSR made a very good, VERY FAST, dangerous, enormous (size of some smaller submarines) "wake homing" torpedo. - Imho, IT WAS THE GREATEST THREAT TO THE CARRIER. I neither recall nor had real data, but think it could go faster than 60 mph under the water while closing on the stern wake of the carrier. Perhaps it could be fired from 25 miles behind the carrier, if it could get that close. The USSR made a few enormous subs that could launch one, (or two?) Fortunately, they made much more noise than US subs and could be taken out by a US sub, but if the launching sub was lying quiet on the bottom and got lucky - a Carrier crossed near by - it might have sunk a carrier. Other than that, there is no way to attack the carrier in its battle group at sea. (On a port call, that is another question - not related to cruise missiles.)
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*I believe Iran has quite a few of them, for more than 20 years, and in the narrow St. of Hormuz, they are something to worry about, especially if launched out of a cave in one of Iran's many off-shore islands. An oil tankeer would be a "sitting duck" for one and even a US warship is not entirely safe - MHO - it they got lucky.

Last edited by a moderator: Feb 22, 2008
9. ### Echo3RomeoOne man wolfpackRegistered Senior Member

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That was a great summary. Well done.

As minor clarifications, I would just add that the CIWS (Phalanx cannon) is going away soon. New ships are getting the Rolling Airframe Missile. Also, most ships do carry SRBOC chaff rockets that are manually fired from the bridge at the same time as a change in course is ordered, the goal being to turn the ship into the "shadow" the chaff creates in the radar beam of the incoming missile, causing the missile to mistake the stationary chaff cloud for the ship that is hauling ass away from the back side of it.

During my time spent with the fleet I learned that CIWS - also known as the abandon ship alarm - is an acronym for "Captain, It Won't Shoot!" Although after watching one of them turn a target into shrapnel and then commence shredding the tow cable up toward its (manned) towing aircraft...I've never been one to doubt its lethality.

Last edited: Feb 22, 2008
10. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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That might be useful for relatively small ship threaten by very stupid missle. By its very nature, radar is able to discriminate distance and the chaff cloud would not make an "opaque shaddow" - I.e. the "hauling ass" ship's large RCS would be seen thru the chaff, but if missile is sufficiently dumb and trigers on the chaff, then it would work. Personnally, if I had a CIWS, I would not want any chaff in the air as if the huge RCS of the ship is in shaddow, surely the tiny nose on RCS of the attacking missle is hidden.

PS on Captain, It won't Shoot = CIWS.
That is a good one, I had not heard before. For the early CIWS versions, unfortunately sometimes true. - Those extremely rapid fire, multiple-barrel guns did jam.

Last edited by a moderator: Feb 22, 2008
11. ### iceauraValued Senior Member

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That and people who have lived through a half dozen generations of these programs, all of them boondoggles hyped to the public with lies, all of them accompanied by widespread undermining of scientific and media integrity, none of them to date demonstrated functional in real life.

Some of them just plain ludicrous. But funded - tens of billions of funded.

If you don't like the influence of W&Co on scientific research and its reporting, consider that Reagan more or less started that kind of defunding of uncooperative scientists, punishing of media outlets that reported unfavored versions of events, etc, and it was for his "Star Wars" nonsense. W&Co are Reagan Redux - often with the same people, even.

12. ### Echo3RomeoOne man wolfpackRegistered Senior Member

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The early ones with electric gun drives had to deal with a slower spinup lag from reduced torque. The Block I and later mounts all use pneumatic gun drives, which run off the ship's LP air supply, and are much more reliable. The current cannons also fire electrically primed ammunition, but I'm fairly sure the earlier Vulcans did too.

Unless you count the PAC-2/PAC-3 Patriots as ABMs (which they are) and regard their 8:8 combat success rate against Iraqi TBMs in the early days of OIF as "real life" (which it is)...

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

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Well... I'm sure that this isn't the appropriate place to discuss the politics of the situation, but from where I'm sitting, Reagan and Bush & Co.'' were both great for me.

Bush has tried to increase the funding to high energy physics (my field) every year since he has been in office, and it was the Reagan administration that made the superconducting supercollider a priority. Either way, most high energy physicists I know all have reached the same conclusion---that it was the democrats who screwed us. You can believe me or not---either way, every high energy physicist that I have talked to all think along the same lines. And most of them are card carrying Democrats. One very senior nuclear theorist put it this way: Republicans are bad for science, Democrats are worse.'' Like it or not, take it or leave it---this is how physicsts that I have talked to think.

And, whether it will ever be a reality or not (probably not) Bush has given a huge increase to high energy physics for FY 2009.

Finally, to put us back on track, I fail to see how funding weapons research is not in the interest of science. Not only does it create beneficial spinoff technologies, it also creates jobs for scientists---in other words, it props up the market, making it more appealing for an intelligent young person to choose a career in science.

14. ### iceauraValued Senior Member

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I believe you about funding for high energy physics and certain weapons research.

But science in general ? Consider the effects of putting such a high percentage of research monies behind "classified" walls. Consider the effects of the loss of integrity under Reagan - the fact that so many researchers took money knowing the overall project was BS, but it would keep their research sort of going, if they could make it fit. Even misrepresenting their stuff.

Scientific American ran a multi-issue analysis of Star Wars, from the technical requiirements and possibilities standpoint, and was almost put out of business by a Republican coordinated advertiser boycott by defense-contracting firms.

And the effects even worse outside of weapons and nuke-related stuff.

An acquaintance of mine during the Reagan years wrote a program for a local hospital adjusting the diagnosis criteria for the doctors - essentially finding the most expensive diagnosis that fit the symptoms, to enter on the charts, to help prevent the Reagan revamping of governmental remuneration from bankrupting them without cutting back on treatment. Of course all the medical data affected by diagnosis are now screwed up, but the penalty for honesty was too great.

You can celebrate the money in your field, but there's a price for dealing with the devil like that.
I found 11/11, counting the US and British aircraft taken out.

If that kind of effectiveness extends to more modern missiles and more sophisticated use, then we have our first strike protector - an ABM system that, in its limited sphere, works ! The first one.

Last edited: Feb 23, 2008
15. ### BenTheManDr. of Physics, Prof. of LoveValued Senior Member

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Speaking from the point of view of Academia, this seems to be more or less how it works. The grant that funds me comes from the Dept. of Energy. What string theory has to do with the DOE I have yet to figure out

16. ### Echo3RomeoOne man wolfpackRegistered Senior Member

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That should be 10/10 then (one Tornado, one F/A-18). Patriot does do pretty well against pilots too inept to fly in their corridor and squawk the right IFF authenticator.

17. ### iceauraValued Senior Member

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Ahh, that human factor.

(I found 9/9 on the scud hits.)

So in theater, but getting fed one at a time from an old, poorly maintained stock used under great pressure, essentially without counter pressure, this version killed three men and saved maybe 60 ? (extrapolating from scud attacks of the past not intercepted).

That's only a bit worse than the ratio during combat against the enemy, in that theater (OK,the 20% friendly kill fraction was not so good, but the numbers are low and uncertain). And scuds were actually shot down, no question, this time. So the systems seem to be improving by that measure at least.
a situation to mind when evaluating administration claims to be funding solar, etc, through DOE grants.

18. ### Echo3RomeoOne man wolfpackRegistered Senior Member

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The Army's official figure is 9/9 against ballistic missile threats, however one of these was a FROG-7 and really doesn't have a flight envelope resembling a TBM so it was omitted. Saddam didn't have any Scuds left in serviceable condition. The TBMs engaged were short-ranged Ababil 100s and al-Samoud 2s.

The ADA units were under a lot of pressure, even if it wasn't from the other side. Phase I of OIF involved a few hundred sorties of friendly aircraft per day, and the airspace deconfliction planning beforehand was utterly torturous. Frankly I'm amazed at how few fratricide incidents we actually suffered.

19. ### Buffalo RoamRegistered Senior Member

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Dan Daily 2 for 2

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

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Actually, I WISH I got as much money as those guys. They fund PRACTICAL physics (at least at the university where I work) quite substantially.

21. ### iceauraValued Senior Member

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Hence the lower case, in my acronym free (prefer) posts.

So are you then claiming that a 20% failure rate, while dealing with outmoded short range battle rockets delivered one at a time from deteriorated and combat-pressured setups without deception etc,

constitutes a successful real world test of an ABM system such as we have been discussing here ?

22. ### Echo3RomeoOne man wolfpackRegistered Senior Member

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March/April 2003 was the first (and only) time any purpose-built ABM system has been deployed to a combat theater and fired its weapons. By all authoritative accounts, its performance was a resounding success. Patriot is only designed to engage short-ranged threats. For upper-tier stuff with longer ranges (and thus higher apogees) there are systems like THAAD and AEGIS BMD. The fratricide incidents don't affect the failure rate of the system. The missiles destroyed their targets. The problem was that they shouldn't have been fired to begin with. So yes it is sufficient to say that we have already seen an ABM system perform operationally.

ADA = air defense artillery, community of a thousand acronyms. I'll try to expand them in the future.

23. ### phlogisticianBannedBanned

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Ish, I guess, but ICBM speeds are relative ground speeds, but orbital velocities aren't, so I guess there's about 1000mph rotation of the Earth to get factored in somewhere, .. and my physics is too rusty!

That's certainly the case for traditional ICBM's, and I guess the targets of US ABM missiles. Manouvering all takes place during the boost phase, before apogee, after that, it should all be predictable. The newer Russian TOPOL missiles are very steerable throughout the flight though, rendering ABM pretty useless. I guess the 'rogue states' argument will be used to justify ABM still however, but I think diplomacy has more chance of success, and more longevity.