Cancer Posted November 10, 2005 Report Share Posted November 10, 2005 APOD link One of the authors of the cited work is a friend of mine ... and a gamer. Quote Link to comment Share on other sites More sharing options...
austenandrews Posted November 10, 2005 Report Share Posted November 10, 2005 Re: Gravitational Tractors Cool. I wonder if it wouldn't be worthwhile to straps rockets onto a few asteroids & collect them at strategic points around the earth, for just such a use. Quote Link to comment Share on other sites More sharing options...
Nyrath Posted November 11, 2005 Report Share Posted November 11, 2005 Re: Gravitational Tractors I wonder if it wouldn't be worthwhile to straps rockets onto a few asteroids & collect them at strategic points around the earth' date=' for just such a use.[/quote'] And the other nations of the world would just trust us not to drop a small asteroid on any nation that annoyed us? I don't think they'd agree. See THE MOON IS A HARSH MISTRESS by Robert Heinlein for details. Quote Link to comment Share on other sites More sharing options...
Curufea Posted November 11, 2005 Report Share Posted November 11, 2005 Re: Gravitational Tractors I'm pretty sure space, like international waters between continents, needs to be diplomatically negotiated over - as it belongs to no one nation. Quote Link to comment Share on other sites More sharing options...
austenandrews Posted November 11, 2005 Report Share Posted November 11, 2005 Re: Gravitational Tractors And the other nations of the world would just trust us not to drop a small asteroid on any nation that annoyed us? I don't think they'd agree. It's not like we can't whomp them out of existence already. Besides these asteroids would be very far away, in terms of ordnance. See THE MOON IS A HARSH MISTRESS by Robert Heinlein for details. Er, I just finished Starship Troopers - I need to cleanse my brain of Heinlein for a bit... Quote Link to comment Share on other sites More sharing options...
Curufea Posted November 11, 2005 Report Share Posted November 11, 2005 Re: Gravitational Tractors It's not like we can't whomp them out of existence already. Besides these asteroids would be very far away, in terms of ordnance. Nice thinkin' there Tex, here's your six shooters, bottle o' moonshine and a horse to ride into town on. Meanwhile - back in the current, non-colonial 21st century - has anyone got anything sensible to add? Quote Link to comment Share on other sites More sharing options...
austenandrews Posted November 11, 2005 Report Share Posted November 11, 2005 Re: Gravitational Tractors Hang on there, New World Man. Are you saying we'll be bound by treaty never, ever to manipulate asteroids? That's going to last about as long as never, ever having nuclear power in space. Quote Link to comment Share on other sites More sharing options...
Nyrath Posted November 11, 2005 Report Share Posted November 11, 2005 Re: Gravitational Tractors Hang on there' date=' New World Man. Are you saying we'll be bound by treaty never, ever to manipulate asteroids? That's going to last about as long as never, ever having nuclear power in space.[/quote'] With the stakes so high, one can see all the nations with spaceflight taking steps to ensure the status quo. All asteroids that could easily be nudged into a collision with Earth would have a retinue of warships from all spacefaring nations, pointing their guns at each other and any other ship approaching said asteroid. http://www.projectrho.com/rocket/rocket3c2.html#massdriver Quote Link to comment Share on other sites More sharing options...
austenandrews Posted November 11, 2005 Report Share Posted November 11, 2005 Re: Gravitational Tractors The thing is, this "gravitational tractor" scheme necessarily involves a certain mass with a certain amount of maneuverability. If you're going to have one of these things around to deflect incoming space rocks, mightn't it be easier to strap engines to a suitable-sized asteroid? As opposed to launching tons of metal into space for the same purpose. In the end, the asteroid tractor shouldn't be any more or less dangerous than the artificial tractor. Not to mention that such deflectors would have to be deployed quite a distance from the earth to be effective. All of this, of course, assumes a higher level of space technology than we currently have, as well as the political will to use it. We can talk about mass drivers and the evils thereof, but let's not derail every thread that involves space objects larger than a 747. Quote Link to comment Share on other sites More sharing options...
Dale A. Ward Posted November 11, 2005 Report Share Posted November 11, 2005 Re: Gravitational Tractors Er' date=' I just finished [i']Starship Troopers[/i] - I need to cleanse my brain of Heinlein for a bit... BLASPHEMER!! Quote Link to comment Share on other sites More sharing options...
austenandrews Posted November 11, 2005 Report Share Posted November 11, 2005 Re: Gravitational Tractors It was well-written, but I'm not big on military procedural whatnot. And his philosophy was, er, amusing. I figured it was ripe for satire and rented the movie shortly thereafter. Turns out I was right, it was lame satire. Quote Link to comment Share on other sites More sharing options...
Nyrath Posted November 12, 2005 Report Share Posted November 12, 2005 Re: Gravitational Tractors It was well-written' date=' but I'm not big on military procedural whatnot. And his philosophy was, er, amusing.[/quote'] Now you have to run out and find a copy of Joe Haldeman's THE FOREVER WAR. Starship Troopers is somewhat right-wing and is very pre-Vietnam. The Forever War is somewhat left-wing and is very post-Vietnam. Reading the two back-to-back is an experience. Assuming your head doesn't explode. If you want something in the middle try John Steakley's ARMOR. Quote Link to comment Share on other sites More sharing options...
austenandrews Posted November 12, 2005 Report Share Posted November 12, 2005 Re: Gravitational Tractors I read The Forever War a few years back. I can see what you mean. I'll have to see if my copy is still around somewhere. Quote Link to comment Share on other sites More sharing options...
Sociotard Posted November 12, 2005 Report Share Posted November 12, 2005 Re: Gravitational Tractors The thing is, this "gravitational tractor" scheme necessarily involves a certain mass with a certain amount of maneuverability. If you're going to have one of these things around to deflect incoming space rocks, mightn't it be easier to strap engines to a suitable-sized asteroid? As opposed to launching tons of metal into space for the same purpose. In the end, the asteroid tractor shouldn't be any more or less dangerous than the artificial tractor. Not to mention that such deflectors would have to be deployed quite a distance from the earth to be effective. All of this, of course, assumes a higher level of space technology than we currently have, as well as the political will to use it. We can talk about mass drivers and the evils thereof, but let's not derail every thread that involves space objects larger than a 747. I think part of the problem with just attaching ion drives to the rock are 1) We'd have to spend a lot of time and money analyzing the internal structure of the asteroid. If memory serves, asteroids are covered with dust, like the moon. In order to attach anything to it, you'd have to dig down to bedrock, and 2) that's assuming the bedrock iteself is one cohesive mass, instead of a few smaller asteroids bound to each other by gravity alone. The beauty of the gravitational pull idea is that it will pull on every particle of the asteroid with the same amount of force (well, proportional to 1/r^2, but depending on how far away they are, that might not be too much of an issue.) As for using this particular toy as a mass driver . . . no. The method they're proposing would take decades of fine tuned nudging. Technically, you could use this to attack, but why on earth would you? Thered be no way to know who you'd want dead in 80 years, unless you're in a very ugly centuries old war. Even then, you'd run the risk of accidentally hitting yourself. Quote Link to comment Share on other sites More sharing options...
ThothAmon Posted November 12, 2005 Report Share Posted November 12, 2005 Re: Gravitational Tractors On a related note, I can think of one way that 'asteroids as weapons' might have some bearing. When the Martian colonies finally decide to do their updated Boston Tea Party they'll find it useful (and easy) to send hunks of the Asteroid Belt towards Earth as incentives towards 'negotiation'. And yes, Starship Troopers is supposed to be satire. OTOH Moon Is A Harsh Mistress pretty much covers everything you'd need to know about near-Earth realpolitik and the practical use of gravity wells Earth already has gravitational tractors - they are called Jupiter and the Moon. The latter has saved old Earth many times (vis impact craters) and Jupiter does a good job at catching debris further out from the centre of the system. Without these celestial bodies methinks we'd have been in an extinction event a while back. Shoemaker-Levy 9 was a fine example of 'what if'. The call for a grav tractor idea should come when you give consideration to objects that may be entering the system on a path that's off the plane of the eclyptic. Main issue with grav tractors are available mass. It's wasteful to send up usable metal and it would take a while to repurpose material from the Asteroid Belt. I'd suggest using spent nuclear fuel as the raw mass, shuttled into orbit by a reliable (non-NASA) means. Kills two birds with one stone - gets rid of harmful waste and helps you build that high mass NEO sweeper. As ever, YMMV. Quote Link to comment Share on other sites More sharing options...
Matt Frisbee Posted November 12, 2005 Report Share Posted November 12, 2005 Re: Gravitational Tractors It's a pretty picture, but given the human race's history with discovering deep space bodies of the mentioned size (200m diameter) we usually find them far too late to do anything that elaborate. Unless the governments of the world get serious about finding Earth-Orbit-Crossing Asteroids, an artist's rendition is about all any sort of asteroid deflection you'll see for the next several decades. As for me, I'm catching the next UFO bound for Miramanee's Planet with that cool obelisk asteroid deflector... Matt "Been-living-in-a-fantasy-universe-longer-than-many-people-have-been-alive" Frisbee Quote Link to comment Share on other sites More sharing options...
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