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Besides, with today's technology there's no reason why we should not be able to kill satellites or incoming missiles on a moment's notice.

If the liberals, or other countries, don't like it...to heck with them!
(sorry, I grew up in east Texas so please cut me some slack)

frankie_the_yankee wrote:

Keith B wrote:Yeah, they saw an explosion and are pretty sure they see a vapor cloud, so sounds like the hydrazine tank exploded. I still wonder how much of this was just an opportunity to try their SBM out vs. really concern about the tank not burining up.

(snip)
It's even more impressive that we hit a sattelite travelling at around 20,000 mph or so. This is much faster than an ICBM. So if we can hit a sattelite with this system, it follows that hitting a much slower ICBM is a piece of cake.

This is a common misconception in orbital motion; the myth that a faster-moving orbiting object has a higher angular velocity. The reality is that you speed up to slow down

Let me explain. There are two components to velocity in orbit that determine the shape of said orbit; the velocity on a tangent to the earth's surface, and the velocity in the direction of earth induced by gravity. Quite simply, you orbit the earth when you're falling towards it, but are moving so fast to the left or right that you keep missing.

Speeding up increases your tangent velocity. The resulting vector created by combining that velocity with that caused by gravity is shallower, closer to the tangent, than a slower tangent velocity. That moves you further away from the earth. You are now moving along an orbit of greater circumference than before, and even though you are moving faster, even at that speed it takes you longer to make a circuit around that orbit than a closer one. So, even though you are moving faster, to an observer on the earth you are moving more slowly across the sky than you would be if you were moving slower and thus closer to the earth.

For example; you can track the progress of the ISS across the sky (on a clear night) using a telescope with very little movement. Compare that to John Glenn's first flight, or for younger folks the progress of the space shuttle as it reenters; near-earth flight appears far faster.

Why is this significant? Because angular velocity determines the ability of a missile to track its target, and the time allowed to acquire the target. The more slowly a target changes angle, the less the missile has to change its angle in order to intercept. A missile can only maneuver so much, and is generally only smart enough to point itself at its target, not predict its path. If the angular change is too great the missile will pass behind its target, which is why fighter pilots are taught how to "outturn" missiles. Similarly, a relatively low-flying ICBM will be able to evade a missile shot at it from underneath, where the same missile on the same path would be able to turn tight enough to destroy a higher-flying satellite even though it may end up turning more to "chase" the satellite.

Liko81 wrote:

frankie_the_yankee wrote:

Keith B wrote:Yeah, they saw an explosion and are pretty sure they see a vapor cloud, so sounds like the hydrazine tank exploded. I still wonder how much of this was just an opportunity to try their SBM out vs. really concern about the tank not burining up.

(snip)
It's even more impressive that we hit a sattelite travelling at around 20,000 mph or so. This is much faster than an ICBM. So if we can hit a sattelite with this system, it follows that hitting a much slower ICBM is a piece of cake.

This is a common misconception in orbital motion; the myth that a faster-moving orbiting object has a higher angular velocity. The reality is that you speed up to slow down

Let me explain. There are two components to velocity in orbit that determine the shape of said orbit; the velocity on a tangent to the earth's surface, and the velocity in the direction of earth induced by gravity. Quite simply, you orbit the earth when you're falling towards it, but are moving so fast to the left or right that you keep missing.

Speeding up increases your tangent velocity. The resulting vector created by combining that velocity with that caused by gravity is shallower, closer to the tangent, than a slower tangent velocity. That moves you further away from the earth. You are now moving along an orbit of greater circumference than before, and even though you are moving faster, even at that speed it takes you longer to make a circuit around that orbit than a closer one. So, even though you are moving faster, to an observer on the earth you are moving more slowly across the sky than you would be if you were moving slower and thus closer to the earth.

For example; you can track the progress of the ISS across the sky (on a clear night) using a telescope with very little movement. Compare that to John Glenn's first flight, or for younger folks the progress of the space shuttle as it reenters; near-earth flight appears far faster.

Why is this significant? Because angular velocity determines the ability of a missile to track its target, and the time allowed to acquire the target. The more slowly a target changes angle, the less the missile has to change its angle in order to intercept. A missile can only maneuver so much, and is generally only smart enough to point itself at its target, not predict its path. If the angular change is too great the missile will pass behind its target, which is why fighter pilots are taught how to "outturn" missiles. Similarly, a relatively low-flying ICBM will be able to evade a missile shot at it from underneath, where the same missile on the same path would be able to turn tight enough to destroy a higher-flying satellite even though it may end up turning more to "chase" the satellite.

O.K.............


So can I get you to go with me next time I go dove hunting.

Pretty sure I am not leading them enough, I always get tangent and angular velocity mixed up.

Whoa, flintnapper. That explanation is waaaaaay too heavy before at least 2 more cups of coffee. Even then, I'll probably just have to stick with Grandpa's advice for quail and jack rabbits: "If you shoot where he IS, you hit where he WAS."

The ultimate sniper shot..............one shot, one kill

Garry N

Greybeard wrote:Whoa, flintnapper. That explanation is waaaaaay too heavy before at least 2 more cups of coffee. Even then, I'll probably just have to stick with Grandpa's advice for quail and jack rabbits: "If you shoot where he IS, you hit where he WAS."

Your Grandpa had a way of putting things succinctly. Just the way I like it!

tallmike wrote:

The Annoyed Man wrote:

KBCraig wrote:China and Russia are howling that this was an "illegal" test of our missile defense system.

Never mind that, just a few short months ago, the Chinese destroyed one of their own missiles - exactly the same way - in an orbital plane inhabited by the satellites of many nations, and resulting in a cloud of orbiting fragments that put the rest of those satellites at risk for the next umpty-ump years. And they did it for no other reason than to test their systems.

Buncha hypocrites, that China.

Im sure they are saying the same thing about us. We cried foul when they shot theirs only to shoot our own so soon after.

There are significant differences between theirs and ours. We shot down a spacecraft full of hydrozene rocket fuel that was in a degrading orbit and would have reentered on its own within a few days, potentially posing a great danger to wherever it came down. It was estimated that the fuel tank might survive reentry.

China blew their satellite up in an orbital plane densely occupied by the spacecraft of several other nations, thereby littering that orbital plane with debris that poses the danger of damaging any other spacecraft it connects with. The spacecraft they blew up was in a stable orbit, and their test recklessly endangered the spacecraft of other nations. Their act was irresponsible, whereas ours was an attempt to mitigate a potential danger. There is a world of difference between the two.

Besides, the technology we used has already been successfully tested. Maybe this gave us an opportunity to do it again, but it was not a test that was crucial to the proof of concept, whereas mitigating the potential danger of simply allowing the craft to reenter was a legitimate concern.

That's just my 2¢.

Liko81 wrote: This is a common misconception in orbital motion; the myth that a faster-moving orbiting object has a higher angular velocity. The reality is that you speed up to slow down

No misconception. The angular velocity between the shooter and the target is mostly dependent on the relationship between the vector representing the target's motion and the position of the shooter. Broadly put, if the vector is oriented so as to be across the line of the shot, the angular velocity, hence the required "lead" to hit it, is much greater than if the vector is headed along the line of the shot (and towards the launcher of course.

An object can be travelling at a very high speed, but if it is headed straight for you, its angular velocity along your line of sight will be small.

My main point was that an object travelling at a higher speed is inherently harder to hit, other things being equal, than an object travelling at a lower speed is. This is because it occuppies any given volume of space for a shorter time, which means that your "bullet" has a smaller window of time in which to intercept it at any one spot.

Sattelites travel faster than ICBMs, and sattelites travel faster at the points of their orbits where they are closest to Earth than when they are farther away. This intercept was planned for a point where the spy sattelite was near its low point to maximize the chances that the resulting pieces encounter the upper reaches of the atmosphere and fall out of orbit as much and as quickly as possible. So it stands to reason that it was going somewhere around 17,000 - 20,000 mph when we intercepted it.

The missile was probably going around 4,000 or 5,000 mph itself. So the combined velocity was some where in the low 20Kmph range. And it stands to reason that the intercept ships were positioned along the orbital path to keep the angular velocity between the path of the sattelite and that of the intercept missile as low as possible.

For all of that, it was an impressive one shot stop. An ICBM is quite a bit slower than a sattelite, somewhere in the 12,000 mph range if memory serves. Also, its path is more vertical, more like a mortar shot than the more circular path of the typical sattelite. So near the target area, the angular velocity of an ICBM with respect to the intercept launcher can in many cases be much less than for a sattelite. (Though this can vary of course depending on how far the intended target is from the intercept site.)

The reason why Russia, China, and some other potential rival nations are objecting is because we can do it, from a sea-based platform, and they can't. We have demonstrated the capability to put ships in blue water anywhere in the world to protect any piece of real estate that we choose to, without asking or needing anyone's permission.

Anyone planning on going into the nuclear blackmail business can't be too happy with that.

Seems to me it would be a good time to be cranking out some more missile destroyers, attack subs to protect them, and other associated hardware as needed.

After all, if the federal government is going to be creating jobs, are we better off creating jobs for shipfitters, engineers, etc. or for a bunch of people to be walking through the fields with bags slung over their shoulders harvesting switchgrass?

The biggest problem is not taking China as a serious threat.
And, here comes Russia back as a serious threat as well.

Both of these nations have alot of cash now and they are
spending quite a bit of it to improve thier military and
increase thier capability.

Our politicians are ignorant idiots for not building up
our military so we can maintain peace thru strength.

A missile going through the atmosphere has a lot more guidance issues that one in the vacuum of space. The missiles are solid rockets that can't be throttled like a liquid or jet engine so guidance is also more complicated and less forgiving.

WildBill wrote:A missile going through the atmosphere has a lot more guidance issues that one in the vacuum of space. The missiles are solid rockets that can't be throttled like a liquid or jet engine so guidance is also more complicated and less forgiving.

That's true in boost phase. But while under boost, they have a huge IR plume that makes them easy to track as long as your interceptor can keep up with them. That's actually the portion of their flight when they are most vulnerable to some type of directed energy weapon like an airborne laser.

For most of their flight they are far above most of the atmosphere and are coasting. That's when they are best tracked with something like the SPY radar that the Aegis system has or whatever is the current upgrade of the PAVE/PAWS land based system.

Only at terminal phase are they back down in the atmosphere. And that's only for a few seconds at most. The only way to pick them off then is with a "point defense" system which could be another laser or something like an upgraded Patriot or THAAD system.

Manuverability is no problem for either one of these methods. The laser strikes at the speed of light so can keep up with any manuver. The Patriot or THAAD has manuver capability of its own.

WildBill wrote:A missile going through the atmosphere has a lot more guidance issues that one in the vacuum of space. The missiles are solid rockets that can't be throttled like a liquid or jet engine so guidance is also more complicated and less forgiving.

To clarify for Frankie, I am talking about the boost and guidance of the "interceptor missile", not the target, which is basically in free fall.