Redirect asteroid by mining it for reaction mass?

[zolotiyeruki]

This is one of those "please tell me what I'm missing, and how I'm horribly wrong and/or stupid for even coming up with this" questions

Could you take a NERVA plus some mining equipment, and use an asteroid's mass for reaction mass?  NERVAs are usually expected to run off hydrogen for efficiency, but you'd need to heft a whole lot of hydrogen to redirect a very large asteroid.  What if instead, you fed the nuclear reactor ground-up asteroid as a propellant?  Off the top of my head, I can think of a few issues, like "how to feed a solid into an engine", and making sure you don't melt the engine itself when vaporizing the asteroid dust.  But those seem like solvable issues.

Or, as an alternative, could you use some other sort of mass driver (catapult of some sort?) to hurl chunks of the asteroid away, gradually changing its path with each launch? 

[Canopus]

The idea to move an asteroid using a mass driver and dust as reaction mass is pretty old, probably as old as the mass driver itself. 

[StrandedonEarth]

Yes, old idea, but not a bad one. Probably something akin to a rail gun launching buckets of tailings. The downside would be that it would turn into dangerous space debris. Might make for awesomely predictable meteor storms though

[Nuke]

probibly better off mining for ices and use some kind of arcjet.

[Ultimate Steve]

8 minutes ago, StrandedonEarth said:

Yes, old idea, but not a bad one. Probably something akin to a rail gun launching buckets of tailings. The downside would be that it would turn into dangerous space debris. Might make for awesomely predictable meteor storms though

Wait...

What if a company had a whole bunch of satellites (16 or so) at different inclinations and orbits, which would shoot out lumps of something designed to burn up on reentry so it would produce a very bright flash in spectacular fashion. It might not be possible to make these small enough to have more than a few per satellite, but the company could sell its service as "rent-a-shooting-star."

[Xd the great]

Asteroids have different compositions, meaning some have more hydrogen than others. Separating hydrogen into a gas (i.e. electrolysis) requires a lot of energy, so i guess you can obtain energy from solar panels. You will also have to bring along a lot of nuclear fuel.

Your idea of using the asteroid as a fuel instead of electrolyting it may work, but it will be hard. The heat and other stuff. Or you can just use nuclear energy to vaporise the asteroid and use the exhaust as thrust.

Or just blow it up, like the movie Armageddon. But it has to be done a few years before impact with earth. the explosion will cause the asteroid to vapourize, basically a mass drive.

Or just paint the asteroid. The sunlight should be strong enough to deflect the asteroid. I suggest doing this for your great-great-great-great-great-grandchildren. It takes quite a long time.

[Shpaget]

You still need to solve the problem of mining itself. Low gravity makes digging tricky.

[kerbiloid]

Redirecting an asteroid, you have to spend energy almost totally on redirecting rock wastes.

[Xd the great]

5 hours ago, Shpaget said:

You still need to solve the problem of mining itself. Low gravity makes digging tricky.

The first asteroid panding was done with a fish spear gun thingy. So landing and staying there should not be hard.

Also, we can use lasers to cut rocks, i guess.

[Nuke]

14 hours ago, Xd the great said:

The first asteroid panding was done with a fish spear gun thingy. So landing and staying there should not be hard.

Also, we can use lasers to cut rocks, i guess.

as far as that goes we could produce thrust by ablating the surface with high power lasers, even remote lasers, perhaps used in conjunction with a mirror sat to get the beam in the best possible location.

[Xd the great]

11 minutes ago, Nuke said:

as far as that goes we could produce thrust by ablating the surface with high power lasers, even remote lasers, perhaps used in conjunction with a mirror sat to get the beam in the best possible location.

This works, but the energy requirement will be high.

[NSEP]

On 6/23/2018 at 4:08 AM, Ultimate Steve said:

Wait...

What if a company had a whole bunch of satellites (16 or so) at different inclinations and orbits, which would shoot out lumps of something designed to burn up on reentry so it would produce a very bright flash in spectacular fashion. It might not be possible to make these small enough to have more than a few per satellite, but the company could sell its service as "rent-a-shooting-star."

This?

https://www.bbc.com/news/av/technology-37928806/shooting-stars-from-space-for-2020-olympics

[kerbiloid]

Spoiler

If redirect an asteroid to the Earth and blow it up before it enters the atmosphere, it would be a whole "Hello inyalowda from beltalowda" firework.

 

[StrandedonEarth]

16 hours ago, Xd the great said:

This works, but the energy requirement will be high.

Probably not a lot more than other methods.

Actually, that's probably a safer option than flinging rubble around the system. A bucket's worth of gravel, or even sand, would wreak havoc on a spacecraft or base. But focusing high-power lasers into a thrust chamber to vaporize the tailings into gas or plasma would be most effective and safer for anything in the distant exhaust stream. A plasma stream could be electromagnetically accelerated for even more thrust.

[kerbiloid]

Disperse the rock into thin dust with ultrasound resonance, ionize it with UV or X-Ray, then accelerate with electromagneticity.

Also. that's how to mine it.

(Cause the ultrasound resonance with microwave heating at resonance frequency).

Edited June 24, 2018 by kerbiloid

[Xd the great]

crazy ideas, but I love it.

[magnemoe]

18 hours ago, NSEP said:

This?

https://www.bbc.com/news/av/technology-37928806/shooting-stars-from-space-for-2020-olympics

Cool idea, however don't see how they get 1000 pellets into an 1u cubesat, worse you need to point retrograde and have an launch mechanism bringing them up to 200 km/h. Yes an air gun has no problems with this but then you need an air tank and an large magazine and they are hard to but probably easier with round bullets. 

[kerbiloid]

4 hours ago, Xd the great said:

crazy ideas

Why ideas? Almost all of them have been studied or already used.

Ultrasonic dispersers, colloid rocket engines (in their powder or suspension version), ionizing radiation, microwave heating.
The only thing not examined afaik is ultrasonic vibration modulated by microwave heating, but I believe in humanity.

Edited June 25, 2018 by kerbiloid

[Xd the great]

well asteroids are huge, small ones are hard to detect, so diverting one to save humanity is hard.

Unless we liberate it. 

[Nuke]

5 hours ago, Xd the great said:

crazy ideas, but I love it.

theres also po' mans orion drive. use nuclear shape charges (pulse units) to ablate surface material turning it into a big thruster. if this is spread out over enough area it should produce a uniform force over the entire surface that will keep rubble piles from coming apart.

Edited June 25, 2018 by Nuke

[Xd the great]

2 hours ago, Nuke said:

theres also po' mans orion drive. use nuclear shape charges (pulse units) to ablate surface material turning it into a big thruster. if this is spread out over enough area it should produce a uniform force over the entire surface that will keep rubble piles from coming apart.

Ah yes, the liberating method.

[magnemoe]

7 hours ago, Nuke said:

theres also po' mans orion drive. use nuclear shape charges (pulse units) to ablate surface material turning it into a big thruster. if this is spread out over enough area it should produce a uniform force over the entire surface that will keep rubble piles from coming apart.

Most suited for emergency redirect of an asteroid on collision course, first we are not sure an rubble pile will come apart. 
Secondly nukes is pretty hard to get release for. 

On the upside you don't need to match trajectory with it nor an large ship. An simple interplanetary probe would work well enough.

[Nuke]

3 hours ago, magnemoe said:

Most suited for emergency redirect of an asteroid on collision course, first we are not sure an rubble pile will come apart. 
Secondly nukes is pretty hard to get release for. 

On the upside you don't need to match trajectory with it nor an large ship. An simple interplanetary probe would work well enough.

just a flyby is all thats needed, detonate facing asteroid, ???, profit!

[kerbiloid]

And every time when somebody tries to aerobrake a redirected useful asteroid, either dynos extinct, or deer get fried.

Edited June 26, 2018 by kerbiloid

[Xd the great]

On 6/26/2018 at 2:59 AM, magnemoe said:

Most suited for emergency redirect of an asteroid on collision course, first we are not sure an rubble pile will come apart. 
Secondly nukes is pretty hard to get release for. 

On the upside you don't need to match trajectory with it nor an large ship. An simple interplanetary probe would work well enough.

Well, if the asteroid breaks apart, its surface area increases, so more of the asteroid should be burnt away.

But you now have 2 or more smmaller nukes incoming, rather than 1...