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Would it then also work to fly a small rocket engine to the asteroid, attach to the asteroid, and turn on the engine to divert the asteroid? It sounds a bit mo

Would it then also work to fly a small rocket engine to the asteroid, attach to the asteroid, and turn on the engine to divert the asteroid? It sounds a bit more precise to execute than the nuclear detonation, but it also sounds like you would have much better control over it this way than with nuclear detonation?

vlovich123 3y ago
Probably much harder to pull off + generate that thrust + carry enough fuel to generate that thrust for rocks > some small mass? Just guessing
TheCapeGreek 3y ago
I'd imagine it sounds simpler but is actually much harder. - Huge amounts of thrust required = likely multiple rocket engines - That means huge amounts of mass and equipment - Then the huge amounts of fuel required for all of those Meanwhile with the nuke you can get away with much lower mass and "just" have to worry about making the bombs and detonating them at the right distance. We invented nukes before we went to the moon, after all.
- Aardwolf 3y ago
  I don't know, if maybe not that much thrust is required in some scenarios, perhaps a tiny alteration of course can already be enough to avoid hitting Earth Of course as you say, if the nukes do it even cheaper, makes sense. Perhaps a bit risky to be launching them though! (sensible risk for a sure-hit asteroid, not for deflecting low-probability ones)
- biomcgary 3y ago
  Or, combine the ideas Project Orion style (https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...)
IlliOnato 3y ago
This is definitely one of the possible approaches, which is being studied too. As other commenters mentioned, this would be much harder technically and much more expensive than "nuking", but in some particular scenarios (I think when an asteroid is very loose and easy to break into large parts) this approach has some advantages. Of all the approaches I've read about the coolest in my mind is to paint a large part of the asteroid surface with high-albedo paint, thus using Yarkovsky effect to alter the orbit. This however requires a lot of paint!
- adolph 3y ago
  Could a similar effect be had by painting half asteroid surface with a lower-than-surface-albedo material like vanta-black? Not certain which would be harder....
  - IlliOnato 3y ago
    I guess if an asteroid is has high albedo already, a dark paint would be better for this purpose then dark. What you want is to make sure that some parts reflect much more light than other parts. However, I don't think you need vanta-black for this. You hit diminishing returns on a thing like this; so something like common soot would do just fine. Most asteroids are rather dark, though.
swader999 3y ago
It depends, many asteroids are quite porous, maybe it would burrow into or through it.
hermitcrab 3y ago
An asteroid could weigh millions of tons. For even a tiny deflection I think you would need quite a few tons of propellant. It would be quite a challenge getting that onto the surface of the asteroid.
sfink 3y ago
The asteroid is coming at the Earth fast. To have enough of an effect, you have to do your thing while it's quite a ways away. That means you have to go pretty fast to get out to it before it gets too close to you. You can blow up a bomb while the ship has a large difference in velocity with the asteroid. You cannot attach a rocket engine when you're traveling 1000m/s past what you're trying to attach it to. So if you take Earth to be your stationary velocity, you need to slow down, stop, and accelerate backwards to catch up to the asteroid's velocity. Acceleration/deceleration requires fuel, or specifically mass. More mass at the same acceleration requires even more fuel. So either you send up a bomb to hit the asteroid with a glancing blow, or you launch a very complicated bit of machinery atop a very very large ship, have it do its delta-V stuff, delicately land on the surface, not so delicately drill in and and anchor to an unpredictable surface, and then start burning the even more fuel that you carried along (at a cost of yet more fuel). All while hoping desperately that no bit of sand or gravel gets into something and sticks it in place while setting things up. I'm liking the bomb approach. I imagine you'd even make use of the speed of impact rather than paying for it. You're essentially installing a rocket engine on the asteroid this way anyway, using its mass as propulsion mass, and you can even send up multiple redundant attempts because you've supposedly calculated the trajectory so precisely that it's enough to add some force in pretty much any direction. (Or the rest of the swarm could disarm themselves when they detect the first successful hit.)

vlovich123 3y ago

Probably much harder to pull off + generate that thrust + carry enough fuel to generate that thrust for rocks > some small mass? Just guessing

TheCapeGreek 3y ago

I'd imagine it sounds simpler but is actually much harder. - Huge amounts of thrust required = likely multiple rocket engines - That means huge amounts of mass and equipment - Then the huge amounts of fuel required for all of those Meanwhile with the nuke you can get away with much lower mass and "just" have to worry about making the bombs and detonating them at the right distance. We invented nukes before we went to the moon, after all.

Aardwolf 3y ago
I don't know, if maybe not that much thrust is required in some scenarios, perhaps a tiny alteration of course can already be enough to avoid hitting Earth Of course as you say, if the nukes do it even cheaper, makes sense. Perhaps a bit risky to be launching them though! (sensible risk for a sure-hit asteroid, not for deflecting low-probability ones)
biomcgary 3y ago
Or, combine the ideas Project Orion style (https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...)

IlliOnato 3y ago

This is definitely one of the possible approaches, which is being studied too. As other commenters mentioned, this would be much harder technically and much more expensive than "nuking", but in some particular scenarios (I think when an asteroid is very loose and easy to break into large parts) this approach has some advantages. Of all the approaches I've read about the coolest in my mind is to paint a large part of the asteroid surface with high-albedo paint, thus using Yarkovsky effect to alter the orbit. This however requires a lot of paint!

adolph 3y ago
Could a similar effect be had by painting half asteroid surface with a lower-than-surface-albedo material like vanta-black? Not certain which would be harder....
- IlliOnato 3y ago
  I guess if an asteroid is has high albedo already, a dark paint would be better for this purpose then dark. What you want is to make sure that some parts reflect much more light than other parts. However, I don't think you need vanta-black for this. You hit diminishing returns on a thing like this; so something like common soot would do just fine. Most asteroids are rather dark, though.

swader999 3y ago

It depends, many asteroids are quite porous, maybe it would burrow into or through it.

hermitcrab 3y ago

An asteroid could weigh millions of tons. For even a tiny deflection I think you would need quite a few tons of propellant. It would be quite a challenge getting that onto the surface of the asteroid.

sfink 3y ago

The asteroid is coming at the Earth fast. To have enough of an effect, you have to do your thing while it's quite a ways away. That means you have to go pretty fast to get out to it before it gets too close to you. You can blow up a bomb while the ship has a large difference in velocity with the asteroid. You cannot attach a rocket engine when you're traveling 1000m/s past what you're trying to attach it to. So if you take Earth to be your stationary velocity, you need to slow down, stop, and accelerate backwards to catch up to the asteroid's velocity. Acceleration/deceleration requires fuel, or specifically mass. More mass at the same acceleration requires even more fuel. So either you send up a bomb to hit the asteroid with a glancing blow, or you launch a very complicated bit of machinery atop a very very large ship, have it do its delta-V stuff, delicately land on the surface, not so delicately drill in and and anchor to an unpredictable surface, and then start burning the even more fuel that you carried along (at a cost of yet more fuel). All while hoping desperately that no bit of sand or gravel gets into something and sticks it in place while setting things up. I'm liking the bomb approach. I imagine you'd even make use of the speed of impact rather than paying for it. You're essentially installing a rocket engine on the asteroid this way anyway, using its mass as propulsion mass, and you can even send up multiple redundant attempts because you've supposedly calculated the trajectory so precisely that it's enough to add some force in pretty much any direction. (Or the rest of the swarm could disarm themselves when they detect the first successful hit.)