Bringing sub-kilometer asteroid to Earth surface for science and/or minerals

[tenkendojo]

On the subject of potential peaceful applications of nuclear explosives for space exploration (other than as spacecraft propulsion), would it possible to use several precisely delivered nuclear explosive charges to "safely (in a highly elastic sense)" bring a sub-kilometer asteroid to Earth surface, for scientific and/or commercial mineral extraction purposes?

While there are plenty of discussions about using nuclear explosives for near Earth object (NEO) impact avoidance, not much is said about using similar methods to intentionally bring asteroids on collision course with Earth for scientific or commercial purposes.

The process would be similar to the approach outlined in the NASA 2006 Near-Earth Object Survey and Deflection Study  (https://www.hq.nasa.gov/office/pao/FOIA/NEO_Analysis_Doc.pdf), except now using SLS to carry either 6-8 variable yield nuclear explosives (up to 1.2 megatons each based on the B83 warhead). The selectable yield of nuclear charges would allow for relatively precise trajectory corrections. 

The target would be a sub-kilometer M-type or metal-rich S, E or O type asteroid, hopefully already on a "convenient" close approach orbit relative to Earh. A few examples I could think of are:
1997 RT: ~300m diameter rare O-type asteroid, thought to be rich in platinum
4660 Nereus: 510 m × 330 m × 241 m, E-type asteroid
(7474) 1992 TC:
(10302) 1989 ML: ~600m diameter, iron nickel & cobalt rich composition
(436724) 2011 UW158: ~300m diameter S-type fast rotator
(48603) 1995 BC2: ~840m diameter
65803 Didymos (1996 GT): ~600m diameter

The bigger challenge is whether we could bring such an asteroid to earth without causing a major global catastrophe. One potential solution is to launch several "batches" of nuclear explosives: the first "batch" would bring the asteroid to a near collision trajectory with Earth. Once the asteroid is closer, a second batch of nuclear explosives would be launched to fine-tune the asteroid's into a deep aerobreaking trajectory into Earth's polar regions (either Antarctica or on the frozen tundra of Alaska/Canada/Greenland etc.) Would that be an viable option?

[Phil Stooke]

Carl Sagan warned about deflecting asteroids because the technology, developed for peaceful uses, might fall into the hands of a mad dictator.  Remind you of anyone? 

But also, an asteroid impact into Greenland ice would not be a gentle 'plop'.  It would create a massive shock wave and throw billions of tons of ice, asteroid debris and anything dredged up from under the ice into the atmosphere.  The people of Alaska, Canada Greenland might object.  Not to mention anyone else anywhere on Earth.

If you want to bring an asteroid within reach for study, the oldish plan to put it in lunar orbit for astronauts to visit would make much more sense, but that was studied and dropped some years ago.

[Coastal Ron]

On the subject of potential peaceful applications of nuclear explosives for space exploration (other than as spacecraft propulsion), would it possible to use several precisely delivered nuclear explosive charges to "safely (in a highly elastic sense)" bring a sub-kilometer asteroid to Earth surface, for scientific and/or commercial mineral extraction purposes?

While there are plenty of discussions about using nuclear explosives for near Earth object (NEO) impact avoidance, not much is said about using similar methods to intentionally bring asteroids on collision course with Earth for scientific or commercial purposes.

If we're not talking about using nuclear weapons for destruction, disabling, or deterrence, of an asteroid, then essentially you're talking about using some form of nuclear pulse propulsion - which is an old idea.

In which case the reason why we don't use such propulsion techniques is because we'd be putting NUCLEAR BOMBS IN SPACE.

No matter how many nice uses of nuclear power there are for space, the same concerns boil down to not trusting everyone to keep the nuclear material safe enough that some "rogue element" won't weaponize them and turn them against the humans on planet Earth.

And this is not purely a political issue, this is one of those "letting the genie out of the bottle" issues humanity faces as we get good at developing technology (biological weapons are a concern too), where we don't know how to keep planet Earth safe from lots of loose nuclear weapons.

So my recommendation would be to focus on solar electric propulsion (SEP), but keep the asteroid FAR FROM Earth, since dropping an asteroid on Earth has been known to do bad things too... 

[mikelepage]

The problem is that nukes are such a blunt instrument: they don't really give you the level of control that you would want in order for there to be no chance of catastrophe. Add to this that most asteroids are rubble piles, and the fact that you'd have to slow them down in cis-lunar space to put them in orbit (probably just above the atmosphere if you want to use the Oberth effect), and there's just no way I see that happening.

Better I think to use large magsails or solar sails based on asteroids to maneuver them so they have regular transits through near-Earth space. To do that, 1) you'd want to select asteroids with orbital periods close to some common fraction that of Earth's. By that I mean ratios close to 3:5, or 2:7, etc and then massage those orbits so they pass near (say) L2 at the same time every x years. 2) You'd also want to select asteroids with relatively slow spin rates, so you can point those mag/solar sails precisely once you build massive reaction wheels (i.e. spinning habitats) within the asteroid. Alternatively, instead of maintaining a constant rendezvous with Earth only, you can use that constant but gentle acceleration to perturb those asteroids into cycler-like orbits between Earth and (insert target here).

[Alex_O]

I don't know how to do calculations of the three-body problem, but here's a creative solution, please criticize. Any asteroid can fall on the Sun, and it's free. Let's drop a massive bouncer on an asteroid. He jumps elastically in the gravitational field of the asteroid, but against the orbital motion of the asteroid. And every fall, the impact of the bouncer into the asteroid greatly slows down the asteroid and it falls into the Sun.
There is a simple magic here, where the force of gravity of the sun slows down the bouncer during an elastic rebound. This creates an asymmetry in the exchange of impulses of the bouncer and the asteroid in favor of the attraction of the Sun. And the asteroid falls on the Sun and approaches the Earth.

There is also useful magic in the curvature of the solar gravity well in the space continuum. This should be taken into account, the asteroid is actually flying down the slope of a large pit, compared to a motorcycle in a circus. If an asteroid under the blows of its bouncer will fall deeper into the gravitational pit of the Sun, then it will be useful for logistics.

As for logistics at the finish, the elephant can be eaten in parts. Useful concentrate can be fired towards the Earth, the Moon, etc., in the form of small cartridges. It will be safe, you just need to install a processing plant on the asteroid.  And if the client is put into orbit as a space plant, then logistics becomes even less.

[edzieba]

Any asteroid can fall on the Sun, and it's free.

No, de-orbiting to impact the sun takes an enormous amount of delta-V. The rest of the post is even less correct.

[deltaV]

I don't know how to do calculations of the three-body problem, but here's a creative solution, please criticize. Any asteroid can fall on the Sun, and it's free. Let's drop a massive bouncer on an asteroid. He jumps elastically in the gravitational field of the asteroid, but against the orbital motion of the asteroid. And every fall, the impact of the bouncer into the asteroid greatly slows down the asteroid and it falls into the Sun.
There is a simple magic here, where the force of gravity of the sun slows down the bouncer during an elastic rebound. This creates an asymmetry in the exchange of impulses of the bouncer and the asteroid in favor of the attraction of the Sun. And the asteroid falls on the Sun and approaches the Earth.

Your idea is a bit vague but seems to violate the conservation of angular momentum of the bouncer/asteroid/sun system.

[Alex_O]

Any asteroid can fall on the Sun, and it's free.

No, de-orbiting to impact the sun takes an enormous amount of delta-V. The rest of the post is even less correct.

No, let's count to three, shall we?
1. We have powerful explosives, I mentally cut off a large piece from the asteroid (I made the Jumper) and detonated the bomb.
2. This Jumper flew up, and the asteroid received the "first" decelerating impulse and begins to fall into the Sun. Slowly!
3. The asteroid has gravity and a massive the Jumper falls on the asteroid and gives the asteroid a new ( the second) decelerating impulse.
4. Then the elastic forces do useful work and push the jumper up, and the asteroid again receives (this is the "third") decelerating impulse.
It's almost like magic.

[darkenfast]

Alex_O:

1. The asteroid is in an orbit around the Sun. Let's assume that it is a circular orbit, to make this easy. The only way to bring it closer to the Sun is to reduce it's velocity in that orbit. Do that however you want, but understand that a huge amount of energy is required to make a significant change to the orbital velocity of the huge mass of that asteroid.

2. Now the asteroid is in a new orbit, an elliptical orbit. The high point of that orbit is at the same distance from the Sun. On the other side of the Sun is the low point of the new orbit.

That's all there is. No magic.

Your "jumper" idea does nothing. Even if your "jumper" mass is on the opposite side of the asteroid to the Sun, it can't get a magical gain in force, because it is under the same influence from the Sun as the asteroid throughout the process, not just on the way down. There is no gain.

[Alex_O]

I don't know how to do calculations of the three-body problem, but here's a creative solution, please criticize. Any asteroid can fall on the Sun, and it's free. Let's drop a massive bouncer on an asteroid. He jumps elastically in the gravitational field of the asteroid, but against the orbital motion of the asteroid. And every fall, the impact of the bouncer into the asteroid greatly slows down the asteroid and it falls into the Sun.
There is a simple magic here, where the force of gravity of the sun slows down the bouncer during an elastic rebound. This creates an asymmetry in the exchange of impulses of the bouncer and the asteroid in favor of the attraction of the Sun. And the asteroid falls on the Sun and approaches the Earth.

Your idea is a bit vague but seems to violate the conservation of angular momentum of the bouncer/asteroid/sun system.

don't know how it will be right, but it seems like an astronaut brought a supply of explosive energy to the asteroid and is making an attempt to make a system with energy recovery. It's easy to increase the efficiency of an asteroid transportation machine using a useful resource of the system - the forces of gravity.

Thinking that gravity is like an external force that acts on the asteroid from the side of the universe, which is locally strongly curved by the gravitational field of the Sun.

I still remember the calculations in celestial mechanics - "Behind the satellite - swim breaststroke!". [/size]
(Read here http://tm.spbstu.ru/images/0/09/Bubliy.pdf)[/size]

1. Introduction. Attraction of a body of finite dimensions
Usually there is no need to remember that a satellite flying in orbit around the Earth is a body, not a material point. When calculating orbits about this,
usually don't remember. But the fact remains: the force of gravity of the Earth acting on a body differs from the force acting on a material point of the same mass as the body, located at the same distance from the center of the Earth as the center of mass of the body. Amazing conclusions can follow from this obvious, but easily forgotten fact!

2 Pulsating Spaceship
Our reasoning boils down to three points:
1) The gravitational force acting on a body of finite dimensions,
different from the force acting on a material point of the same mass,
concentrated at the center of mass of the body.
2) By changing the size and shape of the body, you can change the value
the gravitational force acting on it.
3) These changes in the size and shape of the body can be controlled in such a way that the resulting variations in the force of gravity over time will lead to a significant difference in the trajectory of the body from the original.
The first of these statements is obvious. The second is a consequence of the first. The third assertion will be proved below.

As a result of the described process, the energy spent on “turning on” and “off” the dumbbell is pumped into the energy of movement.
apparatus in orbit, which allows you to disperse the apparatus up to the departure from the Earth's gravitational field. The orbit of the apparatus represents in this case an unwinding spiral with a number of turns equal to the number of dumbbell pulsations. A spacecraft whose orbit changes due to variations in the gravitational force acting on the craft is called a gravitational plane.

The internal forces expended on “turning on” and “off” the dumbbell give a noticeable external effect because (and only because) an external force field exists and interacts. This requires a certain resonant tuning between the external and internal
forces.

[Alex_O]

Alex_O:

1. The asteroid is in an orbit around the Sun. Let's assume that it is a circular orbit, to make this easy. The only way to bring it closer to the Sun is to reduce it's velocity in that orbit. Do that however you want, but understand that a huge amount of energy is required to make a significant change to the orbital velocity of the huge mass of that asteroid.

2. Now the asteroid is in a new orbit, an elliptical orbit. The high point of that orbit is at the same distance from the Sun. On the other side of the Sun is the low point of the new orbit.

That's all there is. No magic.

Your "jumper" idea does nothing. Even if your "jumper" mass is on the opposite side of the asteroid to the Sun, it can't get a magical gain in force, because it is under the same influence from the Sun as the asteroid throughout the process, not just on the way down. There is no gain.

I thought that the jumper gives the first jump along the vector against the rotation of the astroid around the Sun. It takes off to a height of 10 km (slowly) (due to the energy of the explosion of a large nuclear bomb) and falls back due to the gravity of the asteroid. And returns the energy of the explosion back to the asteroid for reuse (energy recovery).
The magic is that the asteroid flies along the slope of a large gravitational pit (funnel), which is created by the gravity of the Sun. And after the first jump, the asteroid deorbits and falls deep into the gravitational hole.
(the hippo fell into the swamp).

Yes, the jumper tries to drag the asteroid behind him (accelerate) by the force of his gravity, at the moment of his flight over the asteroid. But this will be work not only against the force of gravity (inertia) of the asteroid, but also against the powerful force of attraction of the asteroid by the Sun. And it seems that a very useful asymmetry arises here, which will eventually drop the asteroid on the Sun.

Yes, these are small forces, but if the jumper is very elastic, then the jumper will be able to make (conditionally) a million (billion) jumps due to the call of just one nuclear bomb, and we see that the useful result (logistics) already depends on the frequency!!! This is a very beautiful idea - when everything depends on the frequency.

[ppnl]

Alex_O:

1. The asteroid is in an orbit around the Sun. Let's assume that it is a circular orbit, to make this easy. The only way to bring it closer to the Sun is to reduce it's velocity in that orbit. Do that however you want, but understand that a huge amount of energy is required to make a significant change to the orbital velocity of the huge mass of that asteroid.

2. Now the asteroid is in a new orbit, an elliptical orbit. The high point of that orbit is at the same distance from the Sun. On the other side of the Sun is the low point of the new orbit.

That's all there is. No magic.

Your "jumper" idea does nothing. Even if your "jumper" mass is on the opposite side of the asteroid to the Sun, it can't get a magical gain in force, because it is under the same influence from the Sun as the asteroid throughout the process, not just on the way down. There is no gain.

I thought that the jumper gives the first jump along the vector against the rotation of the astroid around the Sun. It takes off to a height of 10 km (slowly) (due to the energy of the explosion of a large nuclear bomb) and falls back due to the gravity of the asteroid. And returns the energy of the explosion back to the asteroid for reuse (energy recovery).
The magic is that the asteroid flies along the slope of a large gravitational pit (funnel), which is created by the gravity of the Sun. And after the first jump, the asteroid deorbits and falls deep into the gravitational hole.
(the hippo fell into the swamp).

Yes, the jumper tries to drag the asteroid behind him (accelerate) by the force of his gravity, at the moment of his flight over the asteroid. But this will be work not only against the force of gravity (inertia) of the asteroid, but also against the powerful force of attraction of the asteroid by the Sun. And it seems that a very useful asymmetry arises here, which will eventually drop the asteroid on the Sun.

Yes, these are small forces, but if the jumper is very elastic, then the jumper will be able to make (conditionally) a million (billion) jumps due to the call of just one nuclear bomb, and we see that the useful result (logistics) already depends on the frequency!!! This is a very beautiful idea - when everything depends on the frequency.

If I understand what you are saying then each jump will slow the asteroid for a bit but then as gravity drags the jumper to a stop the asteroid will speed up again. As gravity pulls the jumper down the asteroid will speed up even more. As the jumper impacts the asteroid it slows down to its original speed. If the jumper bounces then the asteroid will slow again.

Each fall will exactly cancel the effect of each jump in a cycle. This is conservation of momentum.   

[darkenfast]

You cannot generate any more energy than that imparted by the one explosion, especially if your jumper is a chunk of rock blasted off the asteroid. The rock cannot generate energy out of nothing. It will either escape the asteroid and go into it's own orbit around the Sun (while the original asteroid has it's orbit changed as well), OR if it's velocity is not enough to escape, then it will fall back to the asteroid.   It doesn't matter how many times you bounce, or what sort of "elastic" your jumper has. Both the asteroid and the jumper feel the attraction of the Sun. That attraction is defined by the mass of the Sun. It's what keeps the asteroid in its free-fall orbit around it.

What you are talking about is like expecting a bowling ball, thrown up from a trampoline, to keep bouncing higher and higher without any additional energy being added.

Edit to add: This was in reply to Alex_O.

[Alex_O]

Alex_O:

1. The asteroid is in an orbit around the Sun. Let's assume that it is a circular orbit, to make this easy. The only way to bring it closer to the Sun is to reduce it's velocity in that orbit. Do that however you want, but understand that a huge amount of energy is required to make a significant change to the orbital velocity of the huge mass of that asteroid.

2. Now the asteroid is in a new orbit, an elliptical orbit. The high point of that orbit is at the same distance from the Sun. On the other side of the Sun is the low point of the new orbit.

That's all there is. No magic.

Your "jumper" idea does nothing. Even if your "jumper" mass is on the opposite side of the asteroid to the Sun, it can't get a magical gain in force, because it is under the same influence from the Sun as the asteroid throughout the process, not just on the way down. There is no gain.

I thought that the jumper gives the first jump along the vector against the rotation of the astroid around the Sun. It takes off to a height of 10 km (slowly) (due to the energy of the explosion of a large nuclear bomb) and falls back due to the gravity of the asteroid. And returns the energy of the explosion back to the asteroid for reuse (energy recovery).
The magic is that the asteroid flies along the slope of a large gravitational pit (funnel), which is created by the gravity of the Sun. And after the first jump, the asteroid deorbits and falls deep into the gravitational hole.
(the hippo fell into the swamp).

Yes, the jumper tries to drag the asteroid behind him (accelerate) by the force of his gravity, at the moment of his flight over the asteroid. But this will be work not only against the force of gravity (inertia) of the asteroid, but also against the powerful force of attraction of the asteroid by the Sun. And it seems that a very useful asymmetry arises here, which will eventually drop the asteroid on the Sun.

Yes, these are small forces, but if the jumper is very elastic, then the jumper will be able to make (conditionally) a million (billion) jumps due to the call of just one nuclear bomb, and we see that the useful result (logistics) already depends on the frequency!!! This is a very beautiful idea - when everything depends on the frequency.

If I understand what you are saying then each jump will slow the asteroid for a bit but then as gravity drags the jumper to a stop the asteroid will speed up again. As gravity pulls the jumper down the asteroid will speed up even more. As the jumper impacts the asteroid it slows down to its original speed. If the jumper bounces then the asteroid will slow again.

Each fall will exactly cancel the effect of each jump in a cycle. This is conservation of momentum.

You correctly described physics, but this is the physics of two ideal bodies (an asteroid and a jumper) that are at an infinite distance from all bodies. And these are point bodies, like points.

Where there is no curved space-time, no external gravitational fields, no physical vacuum, Unro waves, hidden dimensions of the multidimensional universe and something else, in the form of dark matter or energy.

It's all about the gravitational well, Kip Thorn simply draws the curvilinear space of the near zone of the Sun as a kind of funnel.

The magic is that if the asteroid goes down the slope of the gravitational pit, then it is very difficult to extract the asteroid from this pit (by the forces of the gravitational attraction of the jumper at the time of its next elastic rebound), since it is necessary to overcome the force of attraction of the asteroid to the Sun.

IMHO, this is a problem about the movement of three bodies, where there is 1 body (the Sun) and two bodies (an asteroid and a jumper). And these two bodies make multiple elastic collisions, due to the initial impulse of force from the explosion of the bomb (there was an influx of energy from the outside). It was a powerful bomb, but the speed of the jumper is less than the speed of escape in the asteroid's gravitational field.

[Alex_O]

You cannot generate any more energy than that imparted by the one explosion, especially if your jumper is a chunk of rock blasted off the asteroid. The rock cannot generate energy out of nothing. It will either escape the asteroid and go into it's own orbit around the Sun (while the original asteroid has it's orbit changed as well), OR if it's velocity is not enough to escape, then it will fall back to the asteroid.   It doesn't matter how many times you bounce, or what sort of "elastic" your jumper has. Both the asteroid and the jumper feel the attraction of the Sun. That attraction is defined by the mass of the Sun. It's what keeps the asteroid in its free-fall orbit around it.

What you are talking about is like expecting a bowling ball, thrown up from a trampoline, to keep bouncing higher and higher without any additional energy being added.

Edit to add: This was in reply to Alex_O.

Great. Let's change the task. Let's attach the jumper to the asteroid with a solid spring. And magically, we will instantly stop the orbital rotation of the asteroid, so that it will immediately begin to fall into the Sun along a rectilinear trajectory.

We look at the jumper, what will happen to him? We will see that the jumper's jumps and (frequency??) and amplitude have begun!!! jumps are increasing all the time.

We will see that the gravitational force of the sun does work and part of this work (energy) accumulates in a spring pendulum.

This means that we have built a detector, a sensor that catches the gravitational field of the Sun and this creates a local energy reserve in a local system of two bodies - an asteroid and a jumper.

If this energy is used taking into account the Oberth effect (trajectory), then the asteroid can fly away from the solar system like .. a cork from a bottle.

If this physics is correct, then this energy can be used to slow down the asteroid for our logistics, in principle.

Or in other words - how to drop an asteroid on the Sun, using the energy of the Sun itself through the interface to the forces of gravity.

[edzieba]

Alex_O, your proposal has the exact same issues as the last several oscillating-mass schemes you've posted threads on. You can consult the previous threads you've made for resources people have posted to read in order to learn about how Newtonian mechanics work.

[DanClemmensen]

Alex_O, your proposal has the exact same issues as the last several oscillating-mass schemes you've posted threads on. You can consult the previous threads you've made for resources people have posted to read in order to learn about how Newtonian mechanics work.

Alex_O: Please, please, please learn about conservation of momentum. It is at the very heart of space science.
    https://en.wikipedia.org/wiki/Momentum
Please refrain from posting on subjects relating to change of orbits until you have assimilated this concept, because you are just embarrassing yourself. Basically, unless an outside force acts on a system, then some of the system's mass must leave the system to change the momentum of the rest of the system.

[Alex_O]

Alex_O, your proposal has the exact same issues as the last several oscillating-mass schemes you've posted threads on. You can consult the previous threads you've made for resources people have posted to read in order to learn about how Newtonian mechanics work.

Alex_O: Please, please, please learn about conservation of momentum. It is at the very heart of space science.
    https://en.wikipedia.org/wiki/Momentum
Please refrain from posting on subjects relating to change of orbits until you have assimilated this concept, because you are just embarrassing yourself. Basically, unless an outside force acts on a system, then some of the system's mass must leave the system to change the momentum of the rest of the system.

Thanks for taking the time to read my example. I know that this example discusses magic and that the laws of conservation of energy and momentum cannot be violated. My example is an example for the development of bold creative thinking, brainstorming, this is an example of solving an engineering, logistical problem. It is very unusual and looks like magic. But it is very useful, as it creates strong inspiration for new ideas.

The basic idea is very simple - any body within the solar system tends to fall into the Sun. The gravitational force of the Sun is the strongest force in our location and it was very cool to find a way to create an application interface to this system resource. We need to find a good physical effect. And do not be afraid of "imaginary" violations of conservation laws in the local zone, since the correct answer will be in the exact calculation of the total momentum for all bodies of the solar system, taking into account the change in the momentum of the Sun itself. Do you understand what I just said?

Solving the problems of logistics, people have invented ways to move millions of tons of useful cargo within the planet, through the use of internal energy reserves. This does not violate the laws of conservation of momentum, since the correct answer takes into account changes in the momentum of the planet Earth.

[zubenelgenubi]

Alex, your grasp of physics, as well as your ability to assimilate corrections of said grasp, is just as flawed in the "Advanced Concepts" section as it is in the "New Physics" section.

You continue to trot out the same old wrong idea over and over again.

Thread locked.