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#21
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Hypersonics Overhype
John wrote:
Can someone please tell me how something that's broadcasting that much IR can be called 'stealthy'? Okay...so it may tend to get a bit warm at those speeds :-) .... I assume the "stealth" is supposed to be in regards to radar rather than IR; but it would be interesting to determine how much of the IR would get to the ground if the emitter's at an altitude of 150,000 feet or more, as the atmosphere may soak a lot up. The big advantage of something moving (and maneuvering) at around Mach 5 and those altitudes is that it's going to be very difficult to hit with a ground launched missile unless you have a fair degree of warning of its approach, so that the missile can reach its target's future position when the target also arrives at it. That's easier to do with radar than IR, and the fact that the hypersonic missile can maneuver greatly complicates the intercept problem for the forces trying to intercept it.... you may launch at a predicted position where you assume it's going to be, then it turns... and suddenly your interceptor missile finds that it's heading toward the wrong piece of sky, and that it has too much inertia and too little fuel and time to change its course to achieve a successful intercept. At these speeds even slight turns mean miles away in a matter of a few seconds. If scramjet missiles become widespread, they are going to be a major incentive to develop directed energy weapons to deal with them- as that's one of the few things that could slew around fast enough to target a maneuvering one...otherwise you are going to need things like super Sprint ABM's just to get to them in time. And it seems very likely that they are going to be in a _lot_ of country's inventories around 20 years down the line...even India is working on one. Pat |
#22
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Hypersonics Overhype
"Bill Bonde ( Not the man who knows everything, just the man who knows
the important things )" wrote: The ABC thinks it was a success: http://www.abc.net.au/science/slab/hyshot/default.htm #begin quote did the test go? Well; that's nothing but an account of the test launch, not a summary of the science. Don't confuse the two. D. -- Touch-twice life. Eat. Drink. Laugh. |
#23
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Hypersonics Overhype
Pat Flannery wrote:
At these speeds even slight turns mean miles away in a matter of a few seconds. Keep in mind that this applies to the cruise missile as well as the interceptor, the closer the cruise missile comes to it's target, the less it can maneuver. Take a notional hypersonic cruise missile taking a path from Soviet Russia to Offut AFB. While it's still over the Canadian Shield, it can maneuver practically freely. However, as it approaches the US border, the 'wedge' it can be in and still strike it's target narrows pretty rapidly, since even a minimum radius turn can throw it miles off target. At some point the incoming missile can no longer turn, but must remain more or less on a direct course. What this means is that your defense problem changes from a long range intercept well down range into something close to (but not quite) a point defense intercept. Difficult, but not perhaps requiring directed energy weapons. D. -- Touch-twice life. Eat. Drink. Laugh. |
#24
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Hypersonics Overhype
In article ,
Derek Lyons wrote: Take a notional hypersonic cruise missile taking a path from Soviet Russia to Offut AFB. While it's still over the Canadian Shield, it can maneuver practically freely. However, as it approaches the US border, the 'wedge' it can be in and still strike it's target narrows pretty rapidly, since even a minimum radius turn can throw it miles off target. At some point the incoming missile can no longer turn, but must remain more or less on a direct course. This problem can still be compensated for though, with two primary strategies. 1. The missile can be preprogrammed to make course variations throughout that would make it appear to be aimed at something that it is not. Thus, it can be statically pre-programmed to make last-second course adjustments very close to its target that will throw off the defenders' predictions of where it's headed. The missile is still somewhat vulnerable however since, as you point out, there will still be a point-of-no-evasion some distance from its target. 2. The missile can be preprogrammed with a number of primary and secondary targets and, assuming it is somehow kept updated on enemy countermeasures being deployed against it, can keep varying its course to evade them so long as at least one of its eligible targets is within the 'wedge'. The missile can then evade counter-measures up to the very last second since while it might miss its target by doing so, it will simply allocate a new one. The problem then becomes one of fuel consumption; how long can it keep up the game before running dry. Cheers Bent D -- Bent Dalager - - http://www.pvv.org/~bcd powered by emacs |
#25
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Hypersonics Overhype
Derek Lyons wrote:
Pat Flannery wrote: At these speeds even slight turns mean miles away in a matter of a few seconds. Keep in mind that this applies to the cruise missile as well as the interceptor, the closer the cruise missile comes to it's target, the less it can maneuver. The trick is to have it's target be at the end of a last violent maneuver; and hope the enemy doesn't suspect what exactly the target is until it's too late. Take a notional hypersonic cruise missile taking a path from Soviet Russia to Offut AFB. While it's still over the Canadian Shield, it can maneuver practically freely. However, as it approaches the US border, the 'wedge' it can be in and still strike it's target narrows pretty rapidly, since even a minimum radius turn can throw it miles off target. At some point the incoming missile can no longer turn, but must remain more or less on a direct course. What this means is that your defense problem changes from a long range intercept well down range into something close to (but not quite) a point defense intercept. Difficult, but not perhaps requiring directed energy weapons. It's still going to be a very challenging intercept, especially if the incoming missile uses stealth; another thing that has been looked into is have the incoming missile release submunitions as it approaches it's target, making the task of the defenders more difficult as multiple submunitions must then be dealt with before they arrive. If that technique is used, then the parent missile can zig and zag all over the place as long as it passes at some point close enough to its target or targets in its trajectory that the maneuver capabilities of its submunitions allow the objective to be reached. In either case you have to disperse your ACM (Anti Cruise Missile) interceptor missiles to more potential target sites so that they can have the time to reach any incoming missile or sub-warhead as it approaches. And if you put rocket engines on the submunitions, they may arrive at speeds substantially higher than their parent missile. Pat |
#26
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Hypersonics Overhype
Bent C Dalager wrote:
2. The missile can be preprogrammed with a number of primary and secondary targets and, assuming it is somehow kept updated on enemy countermeasures being deployed against it, can keep varying its course to evade them so long as at least one of its eligible targets is within the 'wedge'. The missile can then evade counter-measures up to the very last second since while it might miss its target by doing so, it will simply allocate a new one. The problem then becomes one of fuel consumption; how long can it keep up the game before running dry. Yeah, if can't hit the ICBM complex at Laputa, it can always head for Barshaw instead. (I'm getting of this image of of a hypersonic missile inbound toward a heavily defended area running into interceptor after interceptor, and going further and further down it's list of strategic targets to attack...finally it sets itself on its last target option... and as he sits in the outhouse of his dacha, the Russian Assistant Undersecretary for Turnip Pest Control Measures gets the greatest and last surprise of his Red Turnip Beetle hating life.) Pat |
#27
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Hypersonics Overhype
In article ,
Derek Lyons wrote: At these speeds even slight turns mean miles away in a matter of a few seconds. Keep in mind that this applies to the cruise missile as well as the interceptor, the closer the cruise missile comes to it's target, the less it can maneuver. Yes and no and kind of. It depends on whether you measure "close" in distance or in time. Given equal availability of aerodynamic lift -- a large assumption, admittedly -- the cross-range the missile can achieve in a given *time* is about the same whether it's doing Mach 0.8 or Mach 8. -- MOST launched 30 June; science observations running | Henry Spencer since Oct; first surprises seen; papers pending. | |
#28
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Hypersonics Overhype
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#30
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Hypersonics Overhype
Derek Lyons wrote:
"Bill Bonde ( Not the man who knows everything, just the man who knows the important things )" wrote: The ABC thinks it was a success: http://www.abc.net.au/science/slab/hyshot/default.htm #begin quote did the test go? Well; that's nothing but an account of the test launch, not a summary of the science. Don't confuse the two. I thought they were claiming that it accelerated the craft in SCRAM mode. Maybe I misread it. |
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