Hi there, i'm trying to write a short sci fi story where they are trying to capture/catch an asteroid. i've been trying to come up with a plusable way of doing it but have hit a brick wall. does anybody have a good idea? Thanks Jim
The only way I can imagine doing it is to land small ion thrusters on the asteroid and use them to slowly alter its trajectory over many years until you brought into orbit around the earth or moon for mining (or whatever else you choose to do with it). Of course mining asteroids wouldn't exactly prove cost effective. Or perhaps have a sun powered laser in space that you fire at one side of asteroids to alter their trajectory for similar results.
Of course, applying force against an object would tend to cause damage..."firing" a laser would mean some sort of impact, which would cause localised stresses - how localised depends upon how focussed the beam is...VERY focussed is likely to have an effect very similar to a bullet causing localised stress to a human...reduce the focus and it would have a similar effect to a bullet hitting a human protected by a bullet-proof vest - localised bruising at least. You'd get a similar effect with the ion thrusters, except that you could probably increase the power gradually, whereas a laser beam would probably hit at maximum force, which would be dissipated as it penetrated. Whatever the means of applying the acceleration/deceleration, there would be stress forces upon what may be a very loosely coherent agglomeration of matter, and which may then disintegrate.
The intention of the laser is that it would heat up one part of the asteroid releasing a stream of gas which would create thrust; similar to the way proximity to the sun creates a comets tail. I wasn't talking about lasers in the nonsense pew-pew sense.
They could prove to be cost effective, but only in the veeeeeeeeerrrrrrryyy long run. Other infrastructural dynamics would have to already be in place (along with the reasons for those infrastructures) for the mining of the asteroid belt to be of any value. You definitely are correct in the idea of "Hey, let's go mine asteroids" as being an economic no-go in and of itself, with nothing else and no other reasons already in place. Your question requires more detail in order to help you. Why are you catching this asteroid? Is it in stable orbit in the asteroid belt or has its orbit been bumped so that it passes near the Earth at some point? Who is funding the catch? Do you care if it breaks? When you catch it, is it to remain in space or is the goal to land it on a planetary body? Lots of questions....
Wrap the asteroid in a huuuge balloon-like container. Fill the space between the balloon and the asteroid with two gases, that when mixed turn into a foam that hardens. Once it's hardened, and the asteroid is safe, attach a ship to the balloon, brake. Park the balloon somewhere, then inject a solvent into the foam that returns it to its gaseous forms, vacuum it up, and reuse. As for the balloon, I'm thinking an icosahedron with a sturdy frame made of carbon nanotubes, to which you can attach the ship. The walls could be made of a fabric, also made of carbon nanotubes. Maybe?
the idea I was going for was that they would select an asteroid, maneuver it into a mass driver and send it to a high orbit ship yard. the ship yard would then break it down and use it build a space station thus saving money on transporting materials from earth.
In which case my initial suggestions would work. You would attach Ion Thrusters and gradually manoeuvre the asteroid little by little into the same orbit as the orbiting ship yard where they could "dock". Or you would use a laser to heat up part of the asteroid which would result in ejected gases and impart thrust upon the asteroid into earth orbit. The advantage of this scheme is that the laser could sit in solar orbit and take power from the sun; and would not have finite fuel tanks. The danger would be that these asteroids would need to be at least partly metallic in nature (to build ships) in which case they would not burn-up in the atmosphere if the calculations were wrong or something unexpected happened. I think it would be a high risk to take and perhaps lunar orbit would be safer. Even then you would be bringing them into earth's gravity well with the risk they would hit earth. They would need to be very small asteroids.
I still see massive economic issues. Your high orbit shipyard is already a space station in and of itself. Who's footing the bill for that and how is the asteroid sourced space station going to offset the initial cost of the shipyard. Investors will be scarce as hen's teeth unless there's a payoff.
I like the idea. But I would mine it in place and ship the materials to the construction site that built the space station parts. Once you are out of the Earth's gravity, thrust is relatively cheap, but moving a very massive object may not be as practical as mining in place.
Have you looked into what Planetary Resources does for a living? Here's an article from their website: http://www.planetaryresources.com/2013/04/nasa-wants-to-bag-an-asteroid/ - Dave
Catch a falling star and put it in your pocket. Save it for a rainy day. I think you need to explain the reason to "catch" the asteroid, is there something special about it or is it simply for scientific curiosity? The size of the asteroid would make a difference on how to catch it possibly, speck of dust to Haley's Comet. And of course what do you mean by catch it anyway, bring it to Earth, put it in orbit around Earth or simply land on it as if catching a ride.
I've heard serious discussions of using light radiation pressure to deflect small asteroids. The idea is to, essentially, "paint" part of the asteroid white or some other reflective color and then use the force of the sunlight to change its orbit. The forces are small so doing this sort of thing takes time and it might be difficult to make radical orbital changes this way.
Well if this is a scifi story then the options are basically limitless. For example if I was going to catch an asteroid there's the good old tractor beam to start with. Or if you had a group of asteroid hunters they might have a ship and send out a bunch of drones that form a web between them out of some kind of field or beams and the asteroid is slowly decelerated in this "net".
