# Rods of God

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If he can't apply the rules of angular momentum, acceleration due to gravity, Newtonian motion etc to an object in orbit, what makes you think he can apply them to a bucket on a rope?

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Cap'n Refsmmat said in post #65 :

Any satelite except ones in geostationary orbit (the correct term being geosynchrous orbit) are moving faster than the earth, unless they are in a high inclination orbit.

actually geostationary is just a special case of geosynchronous. geostationary stays in exactly the same place all the time, geosynchronous has a period of 24h, and may wobble up and down, or do anything else that orbital mechanics allows. so long as it gets back to where it started every 24h, it is geosynchronous. note that I am not including harmonics here i.e. a 12h orbit.

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Sayonara?said in post #71 :

If he can't apply the rules of angular momentum, acceleration due to gravity, Newtonian motion etc to an object in orbit, what makes you think he can apply them to a bucket on a rope?

a neverending supply of hope.

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Radical ++++++ said in post #70 :

so how are you going to get the rod to hit the earth at 17,300 mph, give or take a bit.

imagine a little thought experiment. you have a bucket full of water, and you are spinning it round on a rope, and the bucket is travelling with a velocity of say, 5m/s. your mission, should you choose to accept it, is to hit yourself in the head with this bucket at a velocity of at least 5m/s.

Sayonara³ said in post #71 :

If he can't apply the rules of angular momentum, acceleration due to gravity, Newtonian motion etc to an object in orbit, what makes you think he can apply them to a bucket on a rope?

Hey!

Radical ++++++ said in post #72 :

actually geostationary is just a special case of geosynchronous. geostationary stays in exactly the same place all the time, geosynchronous has a period of 24h, and may wobble up and down, or do anything else that orbital mechanics allows. so long as it gets back to where it started every 24h, it is geosynchronous. note that I am not including harmonics here i.e. a 12h orbit.

No, no, no. Geostationary only stays in the same place relative to the earth. Not in space. Geosynchrous is the same. At least that is what the book I read said. It seems you disagree with my book.

<edit> To make it hit the earth at 17300 mph I would have little wings that convert horizontal velocity to vertical velocity.

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Cap'n Refsmmat said in post #74 :

what?

No, no, no. Geostationary only stays in the same place relative to the earth. Not in space. Geosynchrous is the same. At least that is what the book I read said. It seems you disagree with my book.

I know it is only relative to the earth. I thought that would be blazingly obvious, or it would not be called an orbit.

geosynchronous just means synchronised, such that it has an orbit of one sidereal day. it can still move up and down a bit.

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I mean, hold your hand holding the bucket out so the bucket swings and hits your head.

I guess my book wasn't very specific.

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Cap'n Refsmmat said in post #74 :

Hey!

lol

Cap'n Refsmmat said in post #76 :

I mean, hold your hand holding the bucket out so the bucket swings and hits your head.

I guess my book wasn't very specific.

I think this is Rad's point.

Moving your hand along the rope (pulling it in, in effect), is the same as giving the orbital object extra momentum in the direction of Earth. Wasn't his original question something about "where do you get that energy from"?

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You mean the energy to pull it to the planet? A small rocket or spring ejects it from the satelite. When it hits the atmosphere it then points down to the target, turning horizontal motion into vertical.

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I've heard of the idea of using enriched uranium rods launched from space as bunker busters. Here is how it works:

A satelite carrying the guided rods ejects one downwards out of orbit. Because orbital velocity is 17300 mph, the rod has great speed and penetrating power. When the rod hits the atmosphere it points downwards, transferring the horizontal velocity to vertical at 17300. It is now pointing at the target going straight down. When it hits the target at great speed it shoots through the ground to a predetermined depth. It then explodes and destroys the bunker.

Do you think this is possible?

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If you have the rod on an arm and release your payload, it will continue beside you. If you release it over a spot and have retro rockets attached to slow it to about 1,000 mph in the direction of the Earths spin, it should drop nearly straight down with no excess heat. It will drop intact.

If you have it going counter Earths rotation and aim it into the atmosphere and change its orbit to hit the surface, it will come in at 17,000 mph+ and the acceleration added to change its course. It will generate a great deal of heat as it drops.

Just aman

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Modern rockets don't go counter to earth's rotation, because all that extra speed you get from the earth's spin. THey use that speed so they don't need more fuel.

Whut?

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with the earth rotating over a 1000 mph at the equator, it gives you a nice bit of extra velocity. That's why they don't go the opposite direction. You have to counter that speed.

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You've already discussed this at great length with physicists in another thread, where you were told in explicit detail why it would not work, and why it would be stupidly expensive to make it work.

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If this was a spin-off from another thread, what thread is it... I'll split it up if the topic changed because this is an interesting idea.

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Reopened for Cap'n Refsmmat on the understanding that it does not simply repeat reasoning that was refuted in the other thread...

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Thank you much. I was hoping more than people not subscribed/interested in that thread would post their thoughts here.

fafalone said in post #7 :

If this was a spin-off from another thread, what thread is it... I'll split it up if the topic changed because this is an interesting idea.

Interesting? Thank you! I got it from the book 21st Century Soldier and I believe authors of a book and the military who helped creating it would know what they were talking about.

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Threads split and merged as appropriate.

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Now it looks a little messed up... Oh well. Any comments/arguments/constructive critisism?

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• 4 weeks later...

Ide like to know WHO and WHY keeps changing the thread titles?, as I never wrote to such a thread with title as this.

its most annoying and pointless also!

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The original discussion of this topic was in another engineering thread. Then Ref started this new thread on the same subject, and I split the post from the other thread across. No thread titles changed.

This all happened a while ago.

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perhaps I was asleep

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Iirc Ref and I were the only ones online at the time.

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