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Why can't we send rovers to asteroids and grind up the material into fine powders then launch the propellent back to Earths orbit, and use it as a propellent fuel to go to other planets?
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Because you'd have to collect it in Earth's orbit, store it, and then supply some kind of power source to accelerate it again for thrust. At present ion-drive is simply lighter and cheaper than such a system. A better idea would be to shove a NEO into Earth orbit and mine it for fuel on site.
NB: Not an entirely practical nor a flawless idea, but still a better one I'm afraid.
ANTIcarrot.
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That too is a good idea just launch from the asteroid. Could we nuke it into place faster than a tug could get it here? A h2 bomb or two would get it here, or just use the fuel from the asteroid to get it here instead of hauling it there.
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The problem with nukes is that you lack very good control. a few nukes could get the asteroid moving in the general direction of Earth orbit but you'd need to have some sort of conventional propulsion system to maintain proper control of the thing.
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Once you get it here then just grind it up to a very fine powder then accelerate that powder for propulsion. It would work.
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It would be much more practicle to extract propellant from asteroid material on the asteroid, then send a tanker to a fuel depot in Earth orbit. C-type (carbonaceous chondrite) asteroids are supposed to have some water ice.
Ice + sunlight = LH2/LOX
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Sure, all you have to do is capture one with the right stuff in it or just use it as a propellent. Then blast off of it. Hardly any gravity holding you down.
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Very little gravity, yes, but still a significant delta-v and transfer time.
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RobertDyck,
In addition to the common, water rich carbanaceous chondrites, it's believed many NEAs are extinct comets (like asteroid 1979 VA formerly known as Comet Wilson-Harrington). It's thought extinct comets may have water ice beneath their protective insulating mantles.
On this page I have a drawing of small, unmanned craft designed to extract volatiles from from water rich asteroids:
http://clowder.net/hop/railroad/page11. … age11.html
The "Kuck Mosquitoe" is a design by David Kuck of Oracle, Arizona.
Mark Friedenbach,
While it's true the delta vee and transfer time for main belt asteroids are high, there are many near earth asteroids that have near earth perihelions on a regular basis. Often transfer times and delta vee needed to land on such asteroids are small.
Hop's [url=http://www.amazon.com/Conic-Sections-Celestial-Mechanics-Coloring/dp/1936037106]Orbital Mechanics Coloring Book[/url] - For kids from kindergarten to college.
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Perhaps we can move one of these asteroids into an orbit around the Earth????? A second moon????
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Errorist,
Asteroids worth mining likely will be quite massive. Therefore would be expensive to move into earth orbit. That is why I advocate mining with Kuck Mosquitoes (or using other mining techniques) and sending the mined product to near earth space. These less massive loads are more easily done and would cause much less anxiety than a full blown asteroid approaching our neighborhood.
Hop's [url=http://www.amazon.com/Conic-Sections-Celestial-Mechanics-Coloring/dp/1936037106]Orbital Mechanics Coloring Book[/url] - For kids from kindergarten to college.
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So send box car size loads of the material back to an orbit around Earth. Then ionize the material and use it as a propellant on a spaceship????
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But it takes energy to move that boxcar full... and then, it must be made of ice to get the hydrogen out of it, and that takes gobs of energy too.
There isn't any good reason to put an asteroid into orbit of Earth when we build a real RLV that can launch 100's of tons a year of hydrogen made on Earth.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Tugboat As Lifeboat
The title of the article is misleading but it is about NEO, There danger and the use of tugs to move or to redirect them from Earth bound danger.
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Properly done and there is no danger. Think if you could use one on Europa to get it closer to Jupiter and melt all that ice and turn it into a real Water World. The Tidal forces could melt all the ice.
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http://www.builderau.com.au/program/wor … 322,00.htm
An interesting article noting that a large number of alt-space pioneers made their fortunes with computers and software. It mentions Anousheh Ansari, Paul Allen, Jeff Bezos, Elon Musk and John Carmack.
On this webpage Jim Benson talks about his plans to mine asteroids for propellant:
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Benson enjoys the notoriety from his association with SpaceShipOne, but designing commercial rocket motors only temporarily pays the bills. He's setting his sights much farther into the outer reaches of space to find what he calls "white gold in space"--water.
The idea sounds at once outlandish and startlingly simple. Between Earth and Mars lies an asteroid belt that's much smaller than a similar belt separating Mars from Jupiter. Within the belt, Benson estimates, 20 percent of the particles are dormant comets in which a high percentage of the orbital rocks contain ice under their surface. Benson wants to send a small space miner that can land onto the surface of asteroids and drill a meter into the surface to extract the ice reserves.
What's the significance of ice? Benson believes it will become the rocket fuel for space travel to Mars. His idea is to harness solar power, concentrate its heat, and boil the mined comet ice, powering satellites and space ships with a steam engine. This would let spaceships refuel en route to more distant destinations without lugging up extra reserves.
"I want be the Standard Oil of space," Benson said. "White gold, not black gold. White gold."
Hop's [url=http://www.amazon.com/Conic-Sections-Celestial-Mechanics-Coloring/dp/1936037106]Orbital Mechanics Coloring Book[/url] - For kids from kindergarten to college.
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Why can't we send rovers to asteroids and grind up the material into fine powders then launch the propellent back to Earths orbit, and use it as a propellent fuel to go to other planets?
Do You mean something like this: http://www.neofuel.com/]http://www.neofuel.com/
This nuclear rockets use water from asteroids to propel very big space ships around.
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