North Korea Rocket Launch: Long-Range Missile Fired

[gioua]

http://www.huffingtonpost.com/2012/12/11/north-korea-rocket-launch-2012_n_2280964.html


last reports were they were taking down the launch platform since they scrubbed the launch... then this happens...

 

[ChesusRice]

....So What?

 

[cannabineer]

 

[fb360]

Fuckn right.

"SEOUL/TOKYO, Dec 12 (Reuters) - Isolated and impoverished North Korea launched its second long- range rocket of 2012 on Wednesday and may have finally succeeded in putting a satellite into space, the stated aim of what critics say is a disguised ballistic missile test."

Where's Harrekin when you need him? Told you so buddy.

 

[Harrekin]

Fuckn right.

"SEOUL/TOKYO, Dec 12 (Reuters) - Isolated and impoverished North Korea launched its second long- range rocket of 2012 on Wednesday and may have finally succeeded in putting a satellite into space, the stated aim of what critics say is a disguised ballistic missile test."

Where's Harrekin when you need him? Told you so buddy.

It still doesn't contain a warhead

And I was the one saying ICBM capability is reached by being able to put a satellite in orbit.

They're still quite the leap from being able to deliver and detonate a viable warhead on target tho.

 

[fb360]

It still doesn't contain a warhead

And I was the one saying ICBM capability is reached by being able to put a satellite in orbit.

They're still quite the leap from being able to deliver and detonate a viable warhead on target tho.

My entire argument of thread 1 was that in order to send a missile intercontinental, all you need to do is send it to space, let the Earth rotate into position, and send the missile back down to Earth; You dont send it through the atmosphere. But yes, you did agree with me on that point.

Now that they have succeeded in sending something to space, all they need in the ability to manufacture a warhead, and a targeting system which will reliably guide the missile to the target.

Moving on from that thread though, it will be interesting to see NK's next move

edit;
"They're still quite the leap from being able to deliver and detonate a viable warhead on target tho."
With regards to this statement. They don't need to be close to that technology themselves, just need to communicate with Russia, and badabing badaboom, we have some crazy mofo Koreans with weapons of mass destruction

 

[Harrekin]

My entire argument of thread 1 was that in order to send a missile intercontinental, all you need to do is send it to space, let the Earth rotate into position, and send the missile back down to Earth; You dont send it through the atmosphere. But yes, you did agree with me on that point.

Now that they have succeeded in sending something to space, all they need in the ability to manufacture a warhead, and a targeting system which will reliably guide the missile to the target.

Moving on from that thread though, it will be interesting to see NK's next move

edit;
"They're still quite the leap from being able to deliver and detonate a viable warhead on target tho."
With regards to this statement. They don't need to be close to that technology themselves, just need to communicate with Russia, and badabing badaboom, we have some crazy mofo Koreans with weapons of mass destruction

Unless N.Korea has some kind of Lantean Shield Technology protecting their country, I still don't see them being able to use their nukes due to M.A.D.

 

[cannabineer]

My entire argument of thread 1 was that in order to send a missile intercontinental, all you need to do is send it to space, let the Earth rotate into position, and send the missile back down to Earth; You dont send it through the atmosphere. But yes, you did agree with me on that point.

Now that they have succeeded in sending something to space, all they need in the ability to manufacture a warhead, and a targeting system which will reliably guide the missile to the target.

Moving on from that thread though, it will be interesting to see NK's next move

The bolded would be inefficient. In the extreme case, it would take 24 hours and almost escape velocity to bomb Tokyo from the DPRK using that technique.
A sideways lob is always more efficient, and can be done at suborbital velocities, whereas the straight lob up would require distinctly superorbital speeds. And no matter what, you have to punch through atmosphere both coming and going. The first ballistic missile, the A-4 (weaponized as V-2) spent some seconds effectively above the atmosphere on a military trajectory. cn

 

[fb360]

Unless N.Korea has some kind of Lantean Shield Technology protecting their country, I still don't see them being able to use their nukes due to M.A.D.

Oh yeah, they will be wiped from the face of the Earth for sure. That is independent from them even having the technology.

Sad part is, if they choose to go that route, there would be massive innocent civilian death in SK as well as all the neighbors due to radiation.

The bolded would be inefficient. In the extreme case, it would take 24 hours and almost escape velocity to bomb Tokyo from the DPRK using that technique.
A sideways lob is always more efficient, and can be done at suborbital velocities, whereas the straight lob up would require distinctly superorbital speeds. And no matter what, you have to punch through atmosphere both coming and going. The first ballistic missile, the A-4 (weaponized as V-2) spent some seconds effectively above the atmosphere on a military trajectory. cn

In terms of hitting a target exactly opposite of you on Earth, the most efficient way is to send a missile out of the atmosphere so there is no drag, and then position it, and send it back accordingly.

To send something to space, all you have to do is hit the speed of escape. Furthermore, when I say "straight up", I don't mean literally straight up. The warhead would leave the atmosphere much like a NASA rocket would, and then use lift and gravity to bring it back to Earth and its target. Again, that's the most efficient way in terms of energy, not practicality. (In this example the warhead will only reach terminal velocity on the way back)

Obviously, that would give your enemies too much notice time as you mention, as well as other negating factors.
Lastly, anything through an atmosphere is MUCH LESS efficient than through a vacuum, anyone who tells you otherwise doesn't understand even the most basic of physics.

 

[Harrekin]

Oh yeah, they will be wiped from the face of the Earth for sure. That is independent from them even having the technology.

Sad part is, if they choose to go that route, there would be massive innocent civilian death in SK as well as all the neighbors due to radiation.

Tactical Warheads were invented for exactly such circumstances

 

[fb360]

Tactical Warheads were invented for exactly such circumstances

Yeah, you're right. I was theorizing about some Nuke on Nuke action

 

[cannabineer]

In terms of hitting a target exactly opposite of you on Earth, the most efficient way is to send a missile out of the atmosphere so there is no drag, and then position it, and send it back accordingly.

To send something to space, all you have to do is hit the speed of escape. Furthermore, when I say "straight up", I don't mean literally straight up. The warhead would leave the atmosphere much like a NASA rocket would, and then use lift and gravity to bring it back to Earth and its target. Again, that's the most efficient way in terms of energy, not practicality. (In this example the warhead will only reach terminal velocity on the way back)

Obviously, that would give your enemies too much notice time as you mention, as well as other negating factors.
Lastly, anything through an atmosphere is MUCH LESS efficient than through a vacuum, anyone who tells you otherwise doesn't understand even the most basic of physics.

The bothersome portion of the atmosphere is quite thin. So while the first few miles are usually done vertically, the missiles tilt into their trajectory remarkably soon. The physics of missile ballistics were well-understood even before test articles became available, starting with the A-4 and rapidly escalating to true orbital/intercontinental-capable vehicles. Even on an antipodal lob, the lowest-energy trajectory has an apogee of only a few thousand km. Here's a cool graph showing how range goes up very quickly as terminal velocity approaches orbital (which I remember at about 8 km/s). cn

 

[fb360]

The Troposhere is 14 km or 8.699 miles thick.
The Tropopause is 4 km or 2.485 miles thick.
The Stratosphere, including the ozone layer, is 32 km or 19.88 miles thick.
The Mesosphere is 40 km or 24.85 miles thick.
The Ionosphere (Aurora) is 310 km or 192.6 miles thick.
The total thickness of earth's atmosphere is 400 km or 248.514 miles thick.

If you notice in your second graph, the left is in km. The missile is outside of the atmosphere for 800sec, of a 1100sec flight. You exactly described what I wrote. A missile that leaves the atmosphere for a large portion of its flight to maximize energy efficiency. Thanks for supporting my claim.

edit:
Now, lets take my statement (the extreme) and run with it here.

Lets use all of our energy getting the missile out of the atmosphere. Let us wait while the Earth rotates so we don't need to expend energy to fly horizontally. Let us use gravity, not energy to bring us back to the target with a guidance system using our lift. Consequently, the only energy we used is the energy to get into space, and the energy to stay in position (very little) until we use just a little more to start our descent back to Earth.

That is literally, the most efficient way to use a missile...

You are agreeing with me, but you don't think so.. I agree that the way they actually do it is to maintain a trajectory instead of letting the Earth rotate into position. I was merely stating the most energy efficient example

 

[cannabineer]

The Troposhere is 14 km or 8.699 miles thick.
The Tropopause is 4 km or 2.485 miles thick.
The Stratosphere, including the ozone layer, is 32 km or 19.88 miles thick.
The Mesosphere is 40 km or 24.85 miles thick.
The Ionosphere (Aurora) is 310 km or 192.6 miles thick.
The total thickness of earth's atmosphere is 400 km or 248.514 miles thick.

If you notice in your second graph, the left is in km. The missile is outside of the atmosphere for 800sec, of a 1100sec flight. You exactly described what I wrote. A missile that leaves the atmosphere for a large portion of its flight to maximize energy efficiency. Thanks for supporting my claim.

edit:
Now, lets take my statement (the extreme) and run with it here.

Lets use all of our energy getting the missile out of the atmosphere. Let us wait while the Earth rotates so we don't need to expend energy to fly horizontally. Let us use gravity, not energy to bring us back to the target with a guidance system using our lift. Consequently, the only energy we used is the energy to get into space, and the energy to stay in position (very little) until we use just a little more to start our descent back to Earth.

That is literally, the most efficient way to use a missile...

You are agreeing with me, but you don't think so.. I agree that the way they actually do it is to maintain a trajectory instead of letting the Earth rotate into position. I was merely stating the most energy efficient example

I think you think I was arguing with you.

No worries; I can accommodate.

Let's get the missile out of the atmosphere (by 40km altitude, so still in the stratosphere, we've cleared all but a thousandth of it. The key isn't just thickness but pressure, which is a good read of remaining atmospheric interference.) and then hover. That will require a constant thrust of about 9 m/s² for whatever duration. If the duration is 10 minutes, that's 5.4 km/s impulse peed away on the hover.
It's more efficient to throw the weight over and not just up.

I could also be getting hung on terminology. Lift is generally understood to be aerodynamic, whereas missiles produce thrust. I think/hope I followed your intent though. cn

 

[fb360]

I think you think I was arguing with you.

No worries; I can accommodate.

Let's get the missile out of the atmosphere (by 40km altitude, so still in the stratosphere, we've cleared all but a thousandth of it. The key isn't just thickness but pressure, which is a good read of remaining atmospheric interference.) and then hover. That will require a constant thrust of about 9 m/s² for whatever duration. If the duration is 10 minutes, that's 5.4 km/s impulse peed away on the hover.
It's more efficient to throw the weight over and not just up.

I could also be getting hung on terminology. Lift is generally understood to be aerodynamic, whereas missiles produce thrust. I think/hope I followed your intent though. cn

lol. Wait. So you're telling me it is more efficient to throw something at an angle instead of straight up...

Do the math... Physics works in both x and y. Gravity is always acting 9.8m/s2 down.

If you throw straight up with a force of 100N, you get 100N upwards.
If you throw anything Theta short of 90degrees up, you get 100N*sin(theta), which will always be less than 100N...

If you don't believe me, why do space shuttles take a nearly vertical ascent? They try to maximize efficiency..

I'm not talking about a realistic missile path. I'm talking about getting out of the atmosphere where there is no drag, then you can use a little energy to get to the height of the geosynchronous satellites, or a height that would allow for very little expenditure of fuel. Remember we are in space now, there is no air. A little to go back down when ready, and no thrust once on a path that will lead to going back into the atmosphere when needed. As mentioned, coming back you can use gravity to get to terminal velocity and some lift from the fins for guidance. Our context was a nuclear warhead, so my example was one that would go off on impact (very primitive).

 

[fdd2blk]

[video=youtube;SFlosNODqhE]http://www.youtube.com/watch?v=SFlosNODqhE[/video]

 

[cannabineer]

lol. Wait. So you're telling me it is more efficient to throw something at an angle instead of straight up...

Do the math... Physics works in both x and y. Gravity is always acting 9.8m/s2 down.

If you throw straight up with a force of 100N, you get 100N upwards.
If you throw anything Theta short of 90degrees up, you get 100N*sin(theta), which will always be less than 100N...

If you don't believe me, why do space shuttles take a nearly vertical ascent? They try to maximize efficiency..

I'm not talking about a realistic missile path. I'm talking about getting out of the atmosphere where there is no drag, then you can use a little energy to get to the height of the geosynchronous satellites, or a height that would allow for very little expenditure of fuel. Remember we are in space now, there is no air. A little to go back down when ready, and no thrust once on a path that will lead to going back into the atmosphere when needed. As mentioned, coming back you can use gravity to get to terminal velocity and some lift from the fins for guidance. Our context was a nuclear warhead, so my example was one that would go off on impact (very primitive).

The Shuttle was off vertical after the first mile. Air density decays in an almost exponential manner, which is why the most efficient ("synergistic" in missileer's vernacular) trajectory to orbit or suborbit looks a lot like a rectangular hyperbola. It's really a problem of integral calculus.

As for the force of gravity, it's sensitive to altitude. Even at a low exoatmospheric altitude of 250 km we're already at the 9m/s² mark. cn

 

[drolove]

here we go! time to order my gas masks, just in time for the end of the world!

 

[fb360]

The Shuttle was off vertical after the first mile. Air density decays in an almost exponential manner, which is why the most efficient ("synergistic" in missileer's vernacular) trajectory to orbit or suborbit looks a lot like a rectangular hyperbola. It's really a problem of integral calculus.

As for the force of gravity, it's sensitive to altitude. Even at a low exoatmospheric altitude of 250 km we're already at the 9m/s² mark. cn

I fully understand that gravity is still working. To reiterate, my example was hypothetical. It isn't what actually happens.

Furthermore, for your first part, the reason is because the thickness is less if you cut after most drag releases as you stated. One last time, my example was a simple example. I didn't whip out aerodynamics and calculus

 

[cannabineer]

I fully understand that gravity is still working. To reiterate, my example was hypothetical. It isn't what actually happens.

Furthermore, for your first part, the reason is because the thickness is less if you cut after most drag releases as you stated. One last time, my example was a simple example. I didn't whip out aerodynamics and calculus

Sorry; I do. When I was a youngster, the rocket as a technology fascinated me. cn