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JohnRgt

Self-funded asteroid mapping project

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I'm not sure I understand how you're using "towed", ruveyn. I may have missed something, but it seems the idea is to spin a satellite of some sort around an incoming body, using gravity to change the body's direction. Of course if its the right asteroid we can mine it, either reducing it to nothing or altering its path so we never have to deal with it again . . . (I'm sure I just typed out a Green nightmare, but what can you do.)

http://www.popularmechanics.com/science/space/news/how-to-mine-an-asteroid-11644811

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I'm not sure I understand how you're using "towed", ruveyn. I may have missed something, but it seems the idea is to spin a satellite of some sort around an incoming body, using gravity to change the body's direction. Of course if its the right asteroid we can mine it, either reducing it to nothing or altering its path so we never have to deal with it again . . . (I'm sure I just typed out a Green nightmare, but what can you do.)

http://www.popularmechanics.com/science/space/news/how-to-mine-an-asteroid-11644811

The t.v. bit I saw has an ion powered vessel of small mass sail beside the asteroid to be diverted. If the vessel can "herd" the asteroid over say a period of 15 to 20 years in a particular direction then the asteroid will miss its mark (us). At least that was the theory. From a purely gravitational point of view it makes sense. The small vessel exerts a force on the asteroid. It does not have to be a big force but it has to be exerted over an extended period of time which implies an extended distance over with the force is exerted F x distance is energy and that is how you put a lot of energy (aka. work) on the asteroid to pull it into a better trajectory.

ruveyn

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Towing asteroids. That is way cool and so very rational. Hollywood well never make a move about how a small vessel towed an asteroid and saved the earth.

ruveyn

I'm not sure I understand how you're using "towed", ruveyn. I may have missed something, but it seems the idea is to spin a satellite of some sort around an incoming body, using gravity to change the body's direction. Of course if its the right asteroid we can mine it, either reducing it to nothing or altering its path so we never have to deal with it again . . . (I'm sure I just typed out a Green nightmare, but what can you do.)

http://www.popularmechanics.com/science/space/news/how-to-mine-an-asteroid-11644811

My understanding is that one pulls up alongside the rock, and uses enough power to keep from 'sticking' to it. As you slowly pull away, you drag the rock with you.

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Jules Verne had an interesting idea about what we could get from a meteor in The Hunt for the Meteor: precious metals.

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Jules Verne had an interesting idea about what we could get from a meteor in The Hunt for the Meteor: precious metals.

If we had decent propulsion systems for space vehicles, mining the Asteroids could eventually be done. Unfortunately our space vehicles are propelled by rockets producing hot gases by way of oxidation reactions. This technology is no more advanced -- in principle -- than the solid rockets invented by the Chinese during the Tang Dynasty. The best we can do with this kind of propulsion is burn then coast (i.e. move in free fall in some gravitational field). That means trips to Mars, even at close conjunction will take 9 months in free fall (sometimes called zero-g). That is plenty long enough for the crew'sw bones to become brittle, their muscles atrophy and their bodies bombarded with cosmic rays. A long distance trip outside of our magnetosphere with current and even likely technology is a suicide mission.

What we need is propulsion system than can emit reactants over a very long period of time, (or use light pressure from the sun as a propulsion) and thus achieve speed 2 to 3 orders of magnitude greater than we can achieve now. This would make a trip to the Asteroids a matter of weeks rather than the best part of a year. Also we need designs that produce pseudo-gravity by means of centrifugal force and vessels that are well insulated against cosmic rays. Until that happens we are NOT going to become a real space faring culture. With current technology long trips to beyond the orbit of Mars is more difficult than paddling the width of the Pacific Ocean in a dugout log canoe.

ruveyn

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I'm not sure I understand how you're using "towed", ruveyn...

... From a purely gravitational point of view it makes sense. The small vessel exerts a force on the asteroid. It does not have to be a big force but it has to be exerted over an extended period of time which implies an extended distance over with the force is exerted F x distance is energy and that is how you put a lot of energy (aka. work) on the asteroid to pull it into a better trajectory...

Orbiting masses are 'towed' by what you acknowledge is a gravitational force rather than falling into a gravitational mathematical ditch? :-)

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I'm not sure I understand how you're using "towed", ruveyn...

... From a purely gravitational point of view it makes sense. The small vessel exerts a force on the asteroid. It does not have to be a big force but it has to be exerted over an extended period of time which implies an extended distance over with the force is exerted F x distance is energy and that is how you put a lot of energy (aka. work) on the asteroid to pull it into a better trajectory...

Orbiting masses are 'towed' by what you acknowledge is a gravitational force rather than falling into a gravitational mathematical ditch? :-)

In this instance using the Newtonion locution is easier. The General Theory of Relativity will also explain a "tow" but the mathematics are horrendous.

Sometimes it make more sense to regard gravitation as a force somewhat akin to electro-magnetic forces.

ruveyn

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