An idea: hitting an asteroid...with an asteroid

[55delta]

So from what I've been told, if any of the larger asteroids were found to be on a collision course, trying to blow them apart would just result into almost equally damaging smaller pieces and that they have too much mass and momentum to directly shove off-course.
So I had a crazy idea. Assuming that all nearby asteroids have comparable velocities, then why not, instead of speeding up an object to collide with a larger asteroid, find an asteroid smaller enough to be captured? Then, preserving what momentum the smaller asteroid has as much as possible (or even adding more velocity), re-direct it onto a 'side-on' collision with the larger asteroid in order to knock it a few degrees off its course?

 

I'm not going to pretend that 'playing pool' with asteroids would be easy. I expect that this would only alter a larger asteroid's course by a few degrees. The first of two analogies I'd use to compare this would be trying to knock an out of control tractor-trailer using a speeding coupe hitting directly on the side. The second analogy I'd use is knocking a speeding bullet off-target by shooting it with another bullet. That's not including the challenges of an asteroid re-direct mission. I expect that an collision intercept at those speeds is possible to calculate in, say, a year. But I've never done that before. These are the reasons why I called it a crazy idea.

 

Still, what do you all think about this? Impossible? Plausible? Workable? Already done in KSP?

[Spaceception]

8 minutes ago, 55delta said:

So from what I've been told, if any of the larger asteroids were found to be on a collision course, trying to blow them apart would just result into almost equally damaging smaller pieces and that they have too much mass and momentum to directly shove off-course.
So I had a crazy idea. Assuming that all nearby asteroids have comparable velocities, then why not, instead of speeding up an object to collide with a larger asteroid, find an asteroid smaller enough to be captured? Then, preserving what momentum the smaller asteroid has as much as possible (or even adding more velocity), re-direct it onto a 'side-on' collision with the larger asteroid in order to knock it a few degrees off its course?

 

I'm not going to pretend that 'playing pool' with asteroids would be easy. I expect that this would only alter a larger asteroid's course by a few degrees. The first of two analogies I'd use to compare this would be trying to knock an out of control tractor-trailer using a speeding coupe hitting directly on the side. The second analogy I'd use is knocking a speeding bullet off-target by shooting it with another bullet. That's not including the challenges of an asteroid re-direct mission. I expect that an collision intercept at those speeds is possible to calculate in, say, a year. But I've never done that before. These are the reasons why I called it a crazy idea.

 

Still, what do you all think about this? Impossible? Plausible? Workable? Already done in KSP?

I think It'd be easier to blow up a nuclear bomb next to it Project Orion style to push it off course.

But if the public (And UN) had a firm no no (Which we'd probably break regardless), I think it'd be a good idea, but only if the two Asteroids were made up of metal, otherwise, you'd f*** up the world by spreading the damage, with even more Asteroid.

Or if the Asteroid was really, really big and close, yeah... the Asteroid into Asteroid thing would probably be the best course of action.

Edited January 30, 2016 by Spaceception

[GeneralVeers]

The plan isn't worth banking on to save the planet, because there might not be a nearby asteroid in the right position/trajectory/orbit to pool-shot it into the Doomsday rock.

 

36 minutes ago, 55delta said:

So from what I've been told, if any of the larger asteroids were found to be on a collision course, trying to blow them apart would just result into almost equally damaging smaller pieces and that they have too much mass and momentum to directly shove off-course.

Yeah......there was a thread on that? But things kinda got nasty and flamey and stuff, and ended inconclusively. What we need to do is start firing things at asteroids that are NOT on an impact trajectory, and observing the results to see what actually works.

[AngelLestat]

I like the idea.. because It has dual use.
1-We can capture in the most convenient moment (out of danger) an asteroid (with a big % of water) in a highly elliptical orbit, we paint the asteroid with a high albedo layer to avoid melting and damage from light..  
Meanwhile we are out of danger, we use the asteroid as a refuel station, we install a nuclear reactor in its surface which energy help us to process the fuel and to get water (between other things).
We can also steal speed to its elliptical orbit (which will reduce its apo) to push our ships to higher orbits (not sure how it will be the best way) 

2-In case an asteroid menace earth, we use the nuclear reactor to provide propulsion using the water of the asteroid as propellent. 
Although I guess this will only would work for those menaces that are found in the same ecliptic.  

[*Aqua*]

Are asteroids hard enough for pool billiard?

I think the 'defender asteroid' (the one you shoot from Earth) will only blow a piece of the 'attacker asteroid' away or maybe it'll shatter into numberous smaller pieces which are still on their collision course with Earth.

[fredinno]

1 hour ago, *Aqua* said:

Are asteroids hard enough for pool billiard?

I think the 'defender asteroid' (the one you shoot from Earth) will only blow a piece of the 'attacker asteroid' away or maybe it'll shatter into numberous smaller pieces which are still on their collision course with Earth.

Most asteroids are rubble piles, so yes, this will not end very well. Though we are making kinetic impact experiments for a new Mars mission.

15 hours ago, AngelLestat said:

I like the idea.. because It has dual use.
1-We can capture in the most convenient moment (out of danger) an asteroid (with a big % of water) in a highly elliptical orbit, we paint the asteroid with a high albedo layer to avoid melting and damage from light..  
Meanwhile we are out of danger, we use the asteroid as a refuel station, we install a nuclear reactor in its surface which energy help us to process the fuel and to get water (between other things).
We can also steal speed to its elliptical orbit (which will reduce its apo) to push our ships to higher orbits (not sure how it will be the best way) 

2-In case an asteroid menace earth, we use the nuclear reactor to provide propulsion using the water of the asteroid as propellent. 
Although I guess this will only would work for those menaces that are found in the same ecliptic.  

The amount of delta v needed to put that in orbit would likely shatter the asteroid completely.

[GeneralVeers]

6 hours ago, *Aqua* said:

Are asteroids hard enough for pool billiard?

I think the 'defender asteroid' (the one you shoot from Earth) will only blow a piece of the 'attacker asteroid' away or maybe it'll shatter into numberous smaller pieces which are still on their collision course with Earth.

Uhh.....what if the opposite happens, and the two rocks merge into a single bigger rock??

[Kerbart]

16 minutes ago, WedgeAntilles said:

Uhh.....what if the opposite happens, and the two rocks merge into a single bigger rock??

That sounds like an awesome plot twist for an action movie or tv series.

[fredinno]

1 hour ago, WedgeAntilles said:

Uhh.....what if the opposite happens, and the two rocks merge into a single bigger rock??

Apparently collisions of hard asteroids in the early solar system were about as likely to merge as they were to shatter. Rubble piles were even easier to merge. So that's another reason this is a bad idea. Asteroids are not billiard balls.

[55delta]

Hmm...it seems that everyone who has responded so far didn't seem to understand the entirely of the concept. I thought I'd made the how's and why's of the concept clear, but I guess I couldn't. Oh well, it seems that I just couldn't find the right words to explain what I meant. I don't think I can then.

Oh well, I never was good at making people understand. Well, that's it then. If the gulf of communication is too great, then there is no point in continuing discussing it. Never mind, folks.

[GeneralVeers]

2 hours ago, Kerbart said:

That sounds like an awesome plot twist for an action movie or tv series.

A better twist, especially if it's a movie with Adam Sandler in it: just for once I'd like to see an asteroid movie where everybody thinks the asteroid is gonna wipe out the human race, then the asteroid contacts the atmosphere and, because it's just a lump of dirt, it completely vaporizes, causes absolutely no damage anywhere, and leaves the entire human race going "uhhhhh......what the HELL just happened???" Because, I mean, seriously, every time a movie has a prophecy of disaster in it, the whole audience knows it's gonna come true.

Fredinno nailed it. We all have this tendency to think of asteroids as rocks. Instead of, say, dirt clods.

[Kerbart]

3 minutes ago, WedgeAntilles said:

A better twist, especially if it's a movie with Adam Sandler in it: just for once I'd like to see an asteroid movie where everybody thinks the asteroid is gonna wipe out the human race, then the asteroid contacts the atmosphere and, because it's just a lump of dirt, it completely vaporizes, causes absolutely no damage anywhere, and leaves the entire human race going "uhhhhh......what the HELL just happened???" Because, I mean, seriously, every time a movie has a prophecy of disaster in it, the whole audience knows it's gonna come true

If it's another movie with Adam Sandler in it, civilization is served better by being wiped out by said asteroid...

[GeneralVeers]

Uhhh......yeah, I think it's pretty clear Adam Sandler doesn't have the best interests of the human race at heart, dear GOD some of his material is just SO bad......

[magnemoe]

6 hours ago, WedgeAntilles said:

A better twist, especially if it's a movie with Adam Sandler in it: just for once I'd like to see an asteroid movie where everybody thinks the asteroid is gonna wipe out the human race, then the asteroid contacts the atmosphere and, because it's just a lump of dirt, it completely vaporizes, causes absolutely no damage anywhere, and leaves the entire human race going "uhhhhh......what the HELL just happened???" Because, I mean, seriously, every time a movie has a prophecy of disaster in it, the whole audience knows it's gonna come true.

Fredinno nailed it. We all have this tendency to think of asteroids as rocks. Instead of, say, dirt clods.

For an small asteroid this is very plausible. more so if its so loose it start coming apart by tides, now make it hit close to the edge of earth so i has to pass trough lot of atmosphere. 

An large one is another matter even an high airburst would be dangerous. Even larger and the atmosphere can be ignored. 

[magnemoe]

8 hours ago, 55delta said:

Hmm...it seems that everyone who has responded so far didn't seem to understand the entirely of the concept. I thought I'd made the how's and why's of the concept clear, but I guess I couldn't. Oh well, it seems that I just couldn't find the right words to explain what I meant. I don't think I can then.

Oh well, I never was good at making people understand. Well, that's it then. If the gulf of communication is too great, then there is no point in continuing discussing it. Never mind, folks.

Problem is that this would require more dV it will also require that you move the small asteroid very accurate. 
Try it in KSP

[Karriz]

While this could work, wouldn't it be more efficient to just redirect the asteroid that's in collision course with Earth? You're going to use quite a bit of energy regardless.

There could of course be some situation where some other asteroid is in a easier orbit to reach, and is nearly in a collision course with the other asteroid, so only a small nudge is needed, but I'd expect that to be rare.

EDIT:

In your scenario you mention a bunch of asteroids having roughly the same orbit, and one of them is going to collide with Earth. Then a smaller one would be redirected towards the bigger one. But the amount of energy that you need to add to the smaller asteroid is the exact same you'd need to add to the bigger asteroid in order to avoid a collision with Earth, if I'm thinking this right.

Edited January 31, 2016 by Karriz

[55delta]

4 hours ago, magnemoe said:

Problem is that this would require more dV it will also require that you move the small asteroid very accurate. 
Try it in KSP

Yes, it would require a lot of dv. Also, I mentioned in the OP that it would be difficult. But is it impossible to work out?  Although now that I think about it, does KSP have the time-step to calculate the collision of two objects moving at such orbital speeds, not relative to each other? Maybe it can't be done in KSP after all. 

3 hours ago, Karriz said:

In your scenario you mention a bunch of asteroids having roughly the same orbit, and one of them is going to collide with Earth. Then a smaller one would be redirected towards the bigger one. But the amount of energy that you need to add to the smaller asteroid is the exact same you'd need to add to the bigger asteroid in order to avoid a collision with Earth, if I'm thinking this right.

Who mentioned that? If anything, I was thinking of a collision of two asteroids on courses perpendicular to each other, to ensure the most direct transfer of momentum.

Also, I want to note that whether the asteroids shatter each other, merge, or one was a rubble pile is more of a secondary consideration. This sort of plan (assume that it would need to be done ten years in advance of impact if you assume an Earth defense situation) really only requires that it does one thing right.

Edit:

I guess I should clarify one thing from the OP. I don't assume that you'd want to implement this concept one year from impact, or that it would take a year to implement the plan. Actually, I work it out to about 15 to 20 years. And as I mentioned, this plan likely requires that the asteroids collide 10 years away from an impact on a planet. No, what I mention was that I would expect it to take a year to work out the calculations of the trajectories and where the point of impact would have to be in order to ensure a direct hit. That is, an entire year (assuming supercomputer time) just to work out the math. I haven't even considered what sort of craft would have to do the re-directing yet.

Edited January 31, 2016 by 55delta

[*Aqua*]

15 minutes ago, 55delta said:

That is, an entire year (assuming supercomputer time) just to work out the math.

You don't need that much processing power, maybe a few days to come up with several trajectories and evaluate them. You'll need much, much more time to accurately measure the asteroid's orbit.

[Karriz]

52 minutes ago, 55delta said:

 

Who mentioned that? If anything, I was thinking of a collision of two asteroids on courses perpendicular to each other, to ensure the most direct transfer of momentum.

Okay, in that case it'd work, if all that's needed for an impact is a small nudge, but such a scenario would be somewhat rare.

You said " Assuming that all nearby asteroids have comparable velocities" in the op, by which I thought you meant similar orbits.

Edited January 31, 2016 by Karriz

[55delta]

Oh, that's where the mis-understanding (or at least one of them) was. Warning: wall of text ahead.

 

Just to point out. I'm not asking if this is the easiest method...because it isn't. The easiest method I ever heard of for diverting a killer asteroid I ever heard of (mentioned by Scott Manley, I don't know who proposed it) was to send a satellite into the orbit of the asteroid and use the very minor gravity of the satellite to divert it. Second easiest might be something like Spaceception's suggestion, which I'm going to interpret as attach a Project Orion drive to the side of killer asteroid and keep detonating nukes beside it until the asteroid is diverted. The third easiest I can personally think of is to send an expedition to both mine out and slowly divert the asteroid by some method of propulsion.
Right now, I'm wanting to know if it be possible, or plausible.

 

Now, just to re-itinerate, the idea is divert a killer asteroid (we automatically assume a Earth defense scenario every time killer asteroids are mentioned) by finding an asteroid small enough that it could be maneuvered by a spacecraft, then, while trying to preserve as much momentum of that asteroid as possible, still alter the trajectory so as the two asteroid collide on perpendicular trajectories to alter the trajectory of the killer asteroid (or its resulting debris) by a few degrees radial-out from what the killer asteroid would have impacted. This would need to be as direct an impact as possible, so that as much momentum as possible is transferred between the two asteroids.

 

As for hitting a rubble pile killer asteroid, I would be aiming to divert (at a guess) 90% of its mass from the target and scattering the rest in as wide a space as possible. Admittingly, unless the target of the killer asteroid is a planet with atmosphere, this method of attempting to scatter the killer asteroid wouldn't be effective. Then it would be better to try to divert it with a satellite anyway.

 

Now, I wouldn't launch anything 'from Earth' directly at a killer asteroid, not even if I had another asteroid handy, because the killer asteroid would have too much momentum. If the killer asteroid is big enough and fast enough, collisions from parallel trajectories (even direct head-on) would not be enough to cancel out all that momentum. You could only divert, not stop, a killer asteroid. Even then, you need a considerable distance between a killer asteroid and its target for the few degrees you could divert it to make a difference. That's why I say that plan like this needs to occur 10 year's travel from impact. Since I haven't crafted an actual scenario, this is a guess.

 

So, why an asteroid? The idea depends on an object of comparable (although not equal) momentum to the killer asteroid. Remember, the most important part would be momentum, which needs both mass and speed. This plan assumes that capturing and manipulating an asteroid could be done with a craft smaller than itself. Otherwise it would be easier to just put the capturing craft on that perpendicular trajectory.  I figured that you either have to bring that momentum (either as larger craft, or speeder craft) from your starting point, or you need to find that momentum out in space. This idea assumes that a even a smaller asteroid would have enough momentum, by virtue of both mass and relative speed, to divert a larger asteroid, even if it couldn't stop it. By the same token, you would not want to mine or hollow out any asteroid you wanted to impact a
killer asteroid. Affecting its mass would affect its momentum, which is what you'd want it to retain.

 

Yes, you could suggest using an impactor on the killer asteroid using the same perpendicular trajectory. Just remember that unless the impactor craft had comparable mass, it would need much greater speed to compensate. So the idea of the asteroid is to try an exploit something that already has comparable momentum while being in space. That said, I couldn't begin to guess if you could get greater momentum with an asteroid than an impactor craft.

 

As for where, assume an Earth defense scenario, you'd find an asteroid to use. Well, thanks to Scott Manley, I can think of a few suggestions.

 

Once again, this would be a difficult method of diverting a killer asteroid. First, you need to confirm the existence and exact trajectory of that killer asteroid. Then you need to find a asteroid you could divert, capturing and anchor to the asteroid so that you could divert it (without slowing it in the process), calculating the trajectories of the captured asteroid and then calculating how you want the trajectory altered exactly in order to make that exact crossing of perpandicular trajectories at the right time to make a direct impact. That's not including N-body physics matters, or any shifting if you want to disconnect your capturing spacecraft before impact.
I may have mentioned something about shooting a bullet with a bullet. Very tough, but is it impossible? Could we do it, if we had to? Would it be effective if we could do it?

Edited January 31, 2016 by 55delta

[fredinno]

2 hours ago, 55delta said:

Oh, that's where the mis-understanding (or at least one of them) was. Warning: wall of text ahead.

 

Just to point out. I'm not asking if this is the easiest method...because it isn't. The easiest method I ever heard of for diverting a killer asteroid I ever heard of (mentioned by Scott Manley, I don't know who proposed it) was to send a satellite into the orbit of the asteroid and use the very minor gravity of the satellite to divert it. Second easiest might be something like Spaceception's suggestion, which I'm going to interpret as attach a Project Orion drive to the side of killer asteroid and keep detonating nukes beside it until the asteroid is diverted. The third easiest I can personally think of is to send an expedition to both mine out and slowly divert the asteroid by some method of propulsion.
Right now, I'm wanting to know if it be possible, or plausible.

 

Now, just to re-itinerate, the idea is divert a killer asteroid (we automatically assume a Earth defense scenario every time killer asteroids are mentioned) by finding an asteroid small enough that it could be maneuvered by a spacecraft, then, while trying to preserve as much momentum of that asteroid as possible, still alter the trajectory so as the two asteroid collide on perpendicular trajectories to alter the trajectory of the killer asteroid (or its resulting debris) by a few degrees radial-out from what the killer asteroid would have impacted. This would need to be as direct an impact as possible, so that as much momentum as possible is transferred between the two asteroids.

 

As for hitting a rubble pile killer asteroid, I would be aiming to divert (at a guess) 90% of its mass from the target and scattering the rest in as wide a space as possible. Admittingly, unless the target of the killer asteroid is a planet with atmosphere, this method of attempting to scatter the killer asteroid wouldn't be effective. Then it would be better to try to divert it with a satellite anyway.

 

Now, I wouldn't launch anything 'from Earth' directly at a killer asteroid, not even if I had another asteroid handy, because the killer asteroid would have too much momentum. If the killer asteroid is big enough and fast enough, collisions from parallel trajectories (even direct head-on) would not be enough to cancel out all that momentum. You could only divert, not stop, a killer asteroid. Even then, you need a considerable distance between a killer asteroid and its target for the few degrees you could divert it to make a difference. That's why I say that plan like this needs to occur 10 year's travel from impact. Since I haven't crafted an actual scenario, this is a guess.

 

So, why an asteroid? The idea depends on an object of comparable (although not equal) momentum to the killer asteroid. Remember, the most important part would be momentum, which needs both mass and speed. This plan assumes that capturing and manipulating an asteroid could be done with a craft smaller than itself. Otherwise it would be easier to just put the capturing craft on that perpendicular trajectory.  I figured that you either have to bring that momentum (either as larger craft, or speeder craft) from your starting point, or you need to find that momentum out in space. This idea assumes that a even a smaller asteroid would have enough momentum, by virtue of both mass and relative speed, to divert a larger asteroid, even if it couldn't stop it. By the same token, you would not want to mine or hollow out any asteroid you wanted to impact a
killer asteroid. Affecting its mass would affect its momentum, which is what you'd want it to retain.

 

Yes, you could suggest using an impactor on the killer asteroid using the same perpendicular trajectory. Just remember that unless the impactor craft had comparable mass, it would need much greater speed to compensate. So the idea of the asteroid is to try an exploit something that already has comparable momentum while being in space. That said, I couldn't begin to guess if you could get greater momentum with an asteroid than an impactor craft.

 

As for where, assume an Earth defense scenario, you'd find an asteroid to use. Well, thanks to Scott Manley, I can think of a few suggestions.

 

Once again, this would be a difficult method of diverting a killer asteroid. First, you need to confirm the existence and exact trajectory of that killer asteroid. Then you need to find a asteroid you could divert, capturing and anchor to the asteroid so that you could divert it (without slowing it in the process), calculating the trajectories of the captured asteroid and then calculating how you want the trajectory altered exactly in order to make that exact crossing of perpandicular trajectories at the right time to make a direct impact. That's not including N-body physics matters, or any shifting if you want to disconnect your capturing spacecraft before impact.
I may have mentioned something about shooting a bullet with a bullet. Very tough, but is it impossible? Could we do it, if we had to? Would it be effective if we could do it?

Anything that involves the asteroid shattering is bad- it would just result in the energy being released in the atmosphere instead of the ground.

[AngelLestat]

On 30/1/2016 at 5:01 PM, fredinno said:

The amount of delta v needed to put that in orbit would likely shatter the asteroid completely.

??   Any spacecraft trying to change the orbit of an asteroid will be at very low accelerations, and the "capture" is done using the same gravity of earth to kill the asteroid velocity "gravitation assist" (which does not produce shatter either). The tide force in this case is very small.

On 31/1/2016 at 10:35 PM, GeneralVeers said:

Uhh.....what if the opposite happens, and the two rocks merge into a single bigger rock??

It does not matter because you got what you wanted, divert a tiny bit its trajectory.
Besides, your asteroid of choice to be used as kinetic bomb will be much smaller than the one you want to divert, but it will be much more cost/effective than any thing launched from earth, even nuclear weapons.

23 hours ago, 55delta said:

Hmm...it seems that everyone who has responded so far didn't seem to understand the entirely of the concept.

When you said capture.. I imagine earth capture..  But your way would be very hard, first you need to reach your "tool" asteroid which requires a lot of deltav and time (which each day you wait increase the amount of force needed to being diverted) and you still need the LUCK of having an asteroid that fullfil those orbits needs in that moment of need.

In my way.. you always have an asteroid orbiting earth that works as fuel source, so in case you needed for something else, you can shoot it right away to hit your objective.

That saves a lot of time by many reasons.

Edited February 1, 2016 by AngelLestat

[GeneralVeers]

7 minutes ago, AngelLestat said:

It does not matter because you got what you wanted, divert a tiny bit its trajectory.

Actually, what I want is to divert its trajectory by "enough". Whether or not "a tiny bit" equates to "enough" depends entirely on how far in advance we spot the incoming bogey. That recent impact in Russia (which apparently went undetected until it went KABOOM) proves we're not very good at that last bit.

 

7 minutes ago, AngelLestat said:

Besides, your asteroid of choice to be used as kinetic bomb will be much smaller than the one you want to divert, but it will be much more cost/effective than any thing launched from earth, even nuclear weapons.

We won't know that until we fire some nukes (and other types of weapons) at test asteroids and actually see what happens. Until tested in the real world, every idea in this thread is a theoretical one. We really need to avoid making the mistake they keep making in the movies, where the Anti-Asteroid-Gizmo "hasn't been tested". Because this is not the movies, and when things aren't tested, they usually don't work.

[Newt]

On January 31, 2016 at 1:35 AM, GeneralVeers said:

Uhh.....what if the opposite happens, and the two rocks merge into a single bigger rock??

Then the velocity of the final object will be different then either of the original ones, meaning that probably there will not be a collision with the Earth. Ideally, this is what would happen, not a messy break up.

Edited February 1, 2016 by Newt
added clarification

[RizzoTheRat]

It worked in Red Dwarf