How To Play Asteroids....For Real

[Spacescifi]

I find it disturbing  how in space sims overpowered lasers can blast an asteroid into bits.

For a LOT less energy one could do the SAME thing with railgun cannons.

So to me, railguns and netting are the easiest way I know of to break up small asteroids for mining.

Now if is a BIG asteroid?

Do what Bruce Willis did.

Drill and bore via an auger to create shafts down deep into the asteroid. Insert nukes. Fill up shafts with asteroid debris dust so nukes are surrounded by reaction mass. Detonate. See big rock separate into little rocks. Repeat as desired until the rocks are small enough that the railgun and netting approach is viable.

Your thoughts on this?

 

EDIT: Missiles I really do not see them useful for hitting the rock,  given the fact that a miner ship must close distance to collect anyway.

Yet they are VERY useful for deploying tethers and nets across the asteroid in advance before it breaks, which would save propellant limited miner vessel from having to chase down every rock in every direction.  The rock would break up, but with tethers, it would not fly off into the distance forever requiring a chase.

Funny irony? A miner vessel of this sort could also be used as a warship. So saying you are peaceful asteroid miner won't mean you are not well armed.

In fact to blast asteroids to bits you MUST be well armed.

Edited November 26, 2020 by Spacescifi

[KSK]

A couple of thoughts.

Whatever method you use for breaking up asteroids is going to be very dependent on the asteroid type. A rubble-pile asteroid will behave very differently  to a chunk of nickel-iron when you hit it with a railgun round.

Whatever harvesting method you use will also depend on the asteroid size. Small ones can be scooped up whole, big ones might be better dealt with by building a mining facility on them, although that does come with its own set of problems.

If breaking up the asteroid is the best option then, unless you’re imparting enough delta-V to the asteroid chunks to significantly change their orbit, you’ll end up with a slowly dissipating cloud of asteroid fragments which can be scooped up at leisure. There may be no need for a net.

Deploying nets of any size is going to be a non trivial undertaking.

Again, very dependent on asteroid composition but a laser might be more of a precision instrument than a railgun. Better  for carving off pieces from a larger rock without sending those pieces flying into the distance.

For space ‘sims’, gameplay trumps realism, so any space sim asteroid harvesting is probably going to be a bit dumb.

[Spacescifi]

2 hours ago, KSK said:

A couple of thoughts.

Whatever method you use for breaking up asteroids is going to be very dependent on the asteroid type. A rubble-pile asteroid will behave very differently  to a chunk of nickel-iron when you hit it with a railgun round.

Whatever harvesting method you use will also depend on the asteroid size. Small ones can be scooped up whole, big ones might be better dealt with by building a mining facility on them, although that does come with its own set of problems.

If breaking up the asteroid is the best option then, unless you’re imparting enough delta-V to the asteroid chunks to significantly change their orbit, you’ll end up with a slowly dissipating cloud of asteroid fragments which can be scooped up at leisure. There may be no need for a net.

Deploying nets of any size is going to be a non trivial undertaking.

Again, very dependent on asteroid composition but a laser might be more of a precision instrument than a railgun. Better  for carving off pieces from a larger rock without sending those pieces flying into the distance.

For space ‘sims’, gameplay trumps realism, so any space sim asteroid harvesting is probably going to be a bit dumb.

 

Re space sims; I personally find adding a realistic angle on asteroud mining to only add to the gameplay factor.

I can also tell you that playing oolite trying to chase down broken asteroids is a pain in the butt, made even worse by airplane maneuvering in space since newtonian is not allowed.

Despite the fact they are slow boulders broken up.

Lasers are best for burning, since pulse lasers are the kind of thing NIF uses to ignite nuclear fusion. By the time you can lase pulse blast ANYTHING solid you are into station base power levels, and your vessel would be so heavy with reaction mass for the lasing that it would have very poor thrust, making it a poor mobile spaceship.

That is why I am for now on anti-laser and pro-railgun when it comes to asteroid mining.

I might keep some lasers inside for carving up stored rocks, but tge breaking I can do merrily with slug rounds.

And I am sure there is even a way to shoot rounds with explosive shells if I want extra scattering.

[mikegarrison]

I don't think you understand mining at all. The point of mining is to concentrate the materials you are interested in. Scattering them into little pieces all over space is not the way to go mining.

[Spacescifi]

1 hour ago, mikegarrison said:

I don't think you understand mining at all. The point of mining is to concentrate the materials you are interested in. Scattering them into little pieces all over space is not the way to go mining.

 

Perhaps not. That is what they do in space sims like Oolite before making them small enough to scoop.

Yet I also reckon that it would be faster to break up a large rock to scoop than take all day drilling when you are not sure what's inside...unless we have ways of knowing that too.

 

Maybe beaming it with x-rays will tell you what it has inside I don't know.

[mikegarrison]

16 minutes ago, Spacescifi said:

That is what they do in space sims like Oolite before making them small enough to scoop.

"Rule of cool"

We use explosives to blow rocks apart on Earth, but that's because all the little rocks end up falling into a pile where they can be scooped up. That would not work in what is nearly a zero-g environment.

[KSK]

4 hours ago, Spacescifi said:

Lasers are best for burning, since pulse lasers are the kind of thing NIF uses to ignite nuclear fusion. By the time you can lase pulse blast ANYTHING solid you are into station base power levels, and your vessel would be so heavy with reaction mass for the lasing that it would have very poor thrust, making it a poor mobile spaceship.

Yeah, blasting a rock into chunks with a laser is probably a tall order, but cutting rock with a laser should be feasible. It may take a while though, so as @mikegarrison said, space sims go for rule of cool instead.

Some very simplified notes on lasers based on conversations with a colleague a couple of years back:

You've got two main modes of interaction between a laser beam and a surface. Photothermal - where the material under the laser evaporates or sublimes away (think of the laser as a fancy blowtorch), and photoablative, where the material turns to plasma and dissipates. Which one you get depends critically on the power density of the beam at the surface. Typically,  a continuous wave laser will operate in a photothermal regime because its difficult to build a continuous wave laser capable of reaching the required power density. Pulsed lasers on the other hand can get around that problem by shortening the pulse width. The actual energy per pulse can be relatively low but because its delivered over picoseconds or even femtoseconds, the power densities involved can get quite extreme. When you're dividing by 10^-12 or 10^-15, the numbers can get pretty big pretty fast.

Whilst photoablation sounds pretty violent, in practice everything happens so quickly that very little thermal energy is transferred to the material that isn't directly under the laser beam, so it's a very precise technique with a whole bunch of applications, including dental or medical applications. 

For space rock cutting, I might try an array of semiconductor lasers. They're compact, they convert electricity directly into light (as an LED does), they can get reasonably powerful and, if I remember correctly, they're a good choice (if not the only choice?) if you want a fast or ultrafast pulsed laser.   One semiconductor laser on its own might not be very impressive but - that's why you have an array of them.  Even so, each pass of the laser(s) over the rock won't ablate that much material, so it'll take time to cut off a decent chunk. Not so good for space sims unless you have really dedicated players.  

 

Edited November 26, 2020 by KSK

[Spacescifi]

18 minutes ago, KSK said:

Yeah, blasting a rock into chunks with a laser is probably a tall order, but cutting rock with a laser should be feasible. It may take a while though, so as @mikegarrison said, space sims go for rule of cool instead.

Some very simplified notes on lasers based on conversations with a colleague a couple of years back:

You've got two main modes of interaction between a laser beam and a surface. Photothermal - where the material under the laser evaporates or sublimes away (think of the laser as a fancy blowtorch), and photoablative, where the material turns to plasma and dissipates. Which one you get depends critically on the power density of the beam at the surface. Typically,  a continuous wave laser will operate in a photothermal regime because its difficult to build a continuous wave laser capable of reaching the required power density. Pulsed lasers on the other hand can get around that problem by shortening the pulse width. The actual energy per pulse can be relatively low but because its delivered over picoseconds or even femtoseconds, the power densities involved can get quite extreme. When you're dividing by 10^-12 or 10^-15, the numbers can get pretty big pretty fast.

Whilst photoablation sounds pretty violent, in practice everything happens so quickly that very little thermal energy is transferred to the material that isn't directly under the laser beam, so it's a very precise technique with a whole bunch of applications, including dental or medical applications. 

For space rock cutting, I might try an array of semiconductor lasers. They're compact, they convert electricity directly into light (as an LED does), they can get reasonably powerful and, if I remember correctly, they're a good choice (if not the only choice?) if you want a fast or ultrafast pulsed laser.   One semiconductor laser on its own might not be very impressive but - that's why you have an array of them.  Even so, each pass of the laser(s) over the rock won't ablate that much material, so it'll take time to cut off a decent chunk. Not so good for space sims unless you have really dedicated players.  

 

 

Thanks for the knowledge!

Yeah...lasers ARE useful. If you have the patience.

For gamers they would have to time warp the lasing while occasionally monitoring crew food supply just make sure they don't starve LOL while waiting.

In real life yeah, totally kills lasers as space weapons apart from the bomb pumped lasers which won't be cheap by any means anyway.

Too weak, and take too long.

[Spacescifi]

Actually I just realized we don't even need railguns to break up an asteroid.

Railguns are long range, highspeed slugs.

If a mining vessel is closing in for an intercept, a railgun is overkill, in both the power required and the speed generated. Besides, railgun rails erode over time and the current flow can even melt the rails if high enough.

This is not a real issue for sea ships that have plenty of spare rails and plenty of water to transfer waste heat to.

When closing to intercept an asteroid or any other solid object you wish to blast to bits, old reliable tech works just fine.

And by old and reliable I mean tank cannon guns. Mounted on a miner spaceship.

Still not enough blast?

Add nuclear explosive tank shells as ammunition for the tank cannon.

Joe Schmuckateli knows what I am talking about.

[magnemoe]

1 hour ago, Spacescifi said:

Actually I just realized we don't even need railguns to break up an asteroid.

Railguns are long range, highspeed slugs.

If a mining vessel is closing in for an intercept, a railgun is overkill, in both the power required and the speed generated. Besides, railgun rails erode over time and the current flow can even melt the rails if high enough.

This is not a real issue for sea ships that have plenty of spare rails and plenty of water to transfer waste heat to.

When closing to intercept an asteroid or any other solid object you wish to blast to bits, old reliable tech works just fine.

And by old and reliable I mean tank cannon guns. Mounted on a miner spaceship.

Still not enough blast?

Add nuclear explosive tank shells as ammunition for the tank cannon.

Joe Schmuckateli knows what I am talking about.

This, now why not land an digging robot with an bomb, perhaps you make an crater with an shell land the lander in it and lander push down until digger get a grip. 

But yes guns work: http://www.projectrho.com/public_html/rocket/realdesigns2.php#orionbattleship 
Is very cool but 4K ton, no armor  and 5" guns. That is an destroyer who escort capital ships

[Spacescifi]

3 hours ago, magnemoe said:

This, now why not land an digging robot with an bomb, perhaps you make an crater with an shell land the lander in it and lander push down until digger get a grip. 

But yes guns work: http://www.projectrho.com/public_html/rocket/realdesigns2.php#orionbattleship 
Is very cool but 4K ton, no armor  and 5" guns. That is an destroyer who escort capital ships

 

Personally I think playing 3-D asteroids sim firing tank shell at them while doing newtonian manevers would be quite fun.

Especially because it shows truth for once.

I dislike it when fiction has people believing stuff that is either super hard or impossible is the opposite.

Especially when we have good alternatives that work even BETTER.

Unlike FTL or interstellar travel where we have no alternative besides a very specific set of stories.

You don't need fancy plasma blasters or high powered lasers for blasting space rocks. Since neither are good at blasting anything but stuff that is already prone to combust, which a space rock is not.

Tank guns will do nicely for blasting. Barring that good ole fashioned nukes will.

Now that would be a fun game!

Edited November 27, 2020 by Spacescifi

[monophonic]

2 hours ago, Spacescifi said:

Tank guns will do nicely for blasting. Barring that good ole fashioned nukes will.

Hey, the goal is to break off a piece and collect it for processing. There is a still better technology for doing exactly that, one that doesn't involve imparting any impulse on the mining vessel nor shooting the broken off  pieces in unpredictable directions at inconvenient velocities.

Circular saws. Just cut off the piece you want, you can even have it attached to whatever means you use to move it into the refinery systems ahead of time. No need to waste dV chasing after runaway bits.

Except if your asteroid is a loose pile of rubble like Bennu, shovels.

[Spacescifi]

9 hours ago, monophonic said:

Hey, the goal is to break off a piece and collect it for processing. There is a still better technology for doing exactly that, one that doesn't involve imparting any impulse on the mining vessel nor shooting the broken off  pieces in unpredictable directions at inconvenient velocities.

Circular saws. Just cut off the piece you want, you can even have it attached to whatever means you use to move it into the refinery systems ahead of time. No need to waste dV chasing after runaway bits.

Except if your asteroid is a loose pile of rubble like Bennu, shovels.

 

True...a miner would either need unlimited delta v with good thrust or the ability to generate both gravity and antigravity to get away with chasing blown up rock without consequence.

 

Still, when what you want is deep inside the asteroid, a bit of cannon fire can help.

This a lone miner scenario.

 

Now if you had a whole fleet of miners with diamond blade circular saws attacking a 3k asteroid, that may take less time to turn a profit.

 

As is, unless the stuff is really valuable asteroid mining makes little sense to even involve people at all. Just bots.

 

If people are out asteroid mining  in space because travel is THAT efficient, then they likely already have either gravity/antigravity tech or virtually unlimited high thrust delta v.

It makes no sense otherwise in a setting as far as I am concerned.

Incidentally, with a localized 1g gravity field pod you could capture all that debris easily...but that is scifi I know. Then again...you know me.

[wumpus]

On 11/25/2020 at 11:57 PM, Spacescifi said:

I find it disturbing  how in space sims overpowered lasers can blast an asteroid into bits.

For a LOT less energy one could do the SAME thing with railgun cannons.

When was the last time you saw someone take a railgun or laser into a mineshaft?  We have that "sci-fi worthy" tech right now, as long as you don't care about getting it into space or cooling it in vacuum.  But that simply isn't how you want to mine.

Don't expect mining to change significantly without a gravity field.  Unless your "mining target" is held together like Bennu , in which case you want to "break it apart" with gentle taps and scoop up each "target size" bit.

And of course, the answer to your title question is "You just fly through it.  Avoiding asteroids is entirely optional (although not doing so may lose a tiny percentage of spacecraft)."

[Spacescifi]

7 hours ago, wumpus said:

When was the last time you saw someone take a railgun or laser into a mineshaft?  We have that "sci-fi worthy" tech right now, as long as you don't care about getting it into space or cooling it in vacuum.  But that simply isn't how you want to mine.

Don't expect mining to change significantly without a gravity field.  Unless your "mining target" is held together like Bennu , in which case you want to "break it apart" with gentle taps and scoop up each "target size" bit.

And of course, the answer to your title question is "You just fly through it.  Avoiding asteroids is entirely optional (although not doing so may lose a tiny percentage of spacecraft)."

 

Ya know....perhaps in situ mining at all would be obsolete in a space opera settings?

I mean, the spaceships in popular media have virtually endless high thrust delta V, they do not seem to skimp on thrusting maneuvers at all.

So with those, which are also the most common type in space sims, it would be a lot more economical to just haul asteroids to the nearest base or station designed exclusively for asteroid processing.

Known science does not reward any space vehicle that tries to excel in ALL areas it can possibly find itself in. It rewards specific fine tuning in one or just a few areas.

I reckon even IRL asteroid haulers to and from asteroid processing stations could make a lot more sense than loadimg whatever one can in their cargo bay, as cargo bay space is limited, space itself is virtually unlimited.

What am saying is that your cargo bay is NOT the limit neither should it be your limit. Your limit is whatever max amount of rock your much your ship can push with decent thrust.

With known science, it would take no less than either a lot of fleet to push asteroids around...at great propellant cost I might add, unless waiting decades is ok.

Or using laser propelled sails attached to asteroids which would take decades anyway.

Using space opera logic? You could fly up to a space rock and push it with decent constant acceleration all the way back to base!

It might be a quarter of 1g due to the extra mass penalty on thrust due to the space rock, but some g-force on the crew is a WHOLE lot better than the zero g conditions miners would find themselves in IRL.

Mining takes time, but asterould hauling using space opera constabt acceleration would be a lot FASTER.

Edited November 29, 2020 by Spacescifi

[kerbiloid]

Total delta-V required to catch the debris flying away is nothing, being compared to the delta-V required to evacuate and replace the first mining facility hit by these debris.

As it's said above, here, on the Earth we have a gravity tractor beam to attract the debris back to the planet,

[Spacescifi]

37 minutes ago, kerbiloid said:

Total delta-V required to catch the debris flying away is nothing, being compared to the delta-V required to evacuate and replace the first mining facility hit by these debris.

As it's said above, here, on the Earth we have a gravity tractor beam to attract the debris back to the planet,

 

I know.

My point is that if we take ANY classic scifi starship from a video game especially or a movie that laughs at delta V...it makes in-situ asteroid mining obsolete.

It is easier to just haul bigger rock than can fit in your cargo bay and ship it to a moon base for processing than do it yourself.

Funny how scifi tropes either get obliterated or inverted when the implications of scifi tropes are played out faithfully and logically.

 

Actually asteroid processing in such a system would be mainly for shipping to space habitat stations in deep space or in la grange point orbits.

I think it is the height of silly to use Earth resources to supply a space habitat when you have high thrust virtually endless constant acceleration starships at beck and call that can even do FTL warp.

The ENTIRE universe is your resource.

Use it. Not your precious homeworld!

 

You need tech at scifi trope level to even justify a manned asteroid operation being common.

If tech is so IRL that delta V is actually a big concern, manned missions bring little to no benefit as in-situ mining does not care about humans rotting for lack of gravity and proper food supply.

 

Unless you manage to pull a  Watney and grow veggies from your number twos, sunlight, and asteroid soil LOL.

Edited November 30, 2020 by Spacescifi

[kerbiloid]

If the asteroid is a porous ball of debris (and usually it probably is), then no need in bursting.

In any case it's more useful to land a mining robot with short-range tools to detach the asteroid parts.

Exploding the rocks makes sense only to make them porous (or to move a large portion of ground from the way). And even in this case you should minimize ejecta by drilling deep inside and if possible by covering the place with some cushion. In case of asteroids especially, as everything flown away is lost and dangerous.

[sevenperforce]

I was always amused at the scene in Armageddon where a nuclear device roughly the size of three backyard-grill propane tanks, detonated just 0.039% of the way below the surface,  somehow packs enough energy to split an entire dwarf planet into two pieces and launch them away from each other rapidly enough to pass on both sides of Earth.

Forget Project Orion. We need whatever kind of nuke they were using.

[Spacescifi]

11 hours ago, kerbiloid said:

If the asteroid is a porous ball of debris (and usually it probably is), then no need in bursting.

In any case it's more useful to land a mining robot with short-range tools to detach the asteroid parts.

Exploding the rocks makes sense only to make them porous (or to move a large portion of ground from the way). And even in this case you should minimize ejecta by drilling deep inside and if possible by covering the place with some cushion. In case of asteroids especially, as everything flown away is lost and dangerous.

 

Ya know...when you're serious, you're either brilliant or hilarious, this time the former.

 

So true, classic scifi starships who laugh at delta V would be equipped with boring bots and bomb bots.

Bore bot bores deep, flies out, bomb but flies in and drops bomb, leaves.

Detonate. Boom, a bunch of smaller rocks that are easier to a haul back to base.

I recommend just storing whatever dust the bore bot kicks up, since covering it will lead to all the dust eventually falling back toward the botvand clogging whatever engines got it down in the first place.

 

Don't lose a bot. They cost $$$.

1 hour ago, sevenperforce said:

I was always amused at the scene in Armageddon where a nuclear device roughly the size of three backyard-grill propane tanks, detonated just 0.039% of the way below the surface,  somehow packs enough energy to split an entire dwarf planet into two pieces and launch them away from each other rapidly enough to pass on both sides of Earth.

Forget Project Orion. We need whatever kind of nuke they were using.

 

Antimatter catalyzed nukes 500 of em (small nukes that pack as big a punch as normal size nukes thanks to AM).

 

That't the only way.

Edited November 30, 2020 by Spacescifi

[kerbiloid]

2 hours ago, Spacescifi said:

Antimatter catalyzed nukes

Fission ones. From antiuranium.

[sevenperforce]

19 hours ago, kerbiloid said:

Fission ones. From antiuranium.

We need antiflint, antisteel, and antitinder so that we can create some antisparks and start a merry blaze by combusting antiwood and antioxygen. That'll show'em!

[wumpus]

On 11/30/2020 at 11:37 AM, sevenperforce said:

I was always amused at the scene in Armageddon where a nuclear device roughly the size of three backyard-grill propane tanks, detonated just 0.039% of the way below the surface,  somehow packs enough energy to split an entire dwarf planet into two pieces and launch them away from each other rapidly enough to pass on both sides of Earth.

Forget Project Orion. We need whatever kind of nuke they were using.

If it is anything like Bennu, you wouldn't need a nuke.  Just some TNT the size of three backyard-grill propane tanks and you are set.  Just make sure you do it early enough that most of the asteroid drifts out of the capture radius of Earth's gravity well: a dispersed asteroid probably will burn up in the atmosphere, but the Earth could be missing summers for years if you dumped the mass of a dwarf planet into the atmosphere.

[sevenperforce]

6 minutes ago, wumpus said:

If it is anything like Bennu, you wouldn't need a nuke.  Just some TNT the size of three backyard-grill propane tanks and you are set.  Just make sure you do it early enough that most of the asteroid drifts out of the capture radius of Earth's gravity well: a dispersed asteroid probably will burn up in the atmosphere, but the Earth could be missing summers for years if you dumped the mass of a dwarf planet into the atmosphere.

In the movie, the explanation was that a "rogue comet" had knocked the "Texas-sized" asteroid out of the asteroid belt. We can do the math for a gravity assist as an elastic collision.

Dawn needed 7.8 km/s to get to Vesta, which was a spiral trajectory (lower efficiency) but also used a Mars gravity assist, so 7.8 km/s is probably about right for the injection or departure dV from the asteroid belt to an Earth-crossing trajectory. Your "Texas-sized asteroid" is whirling between Mars and Jupiter at around 17 km/s. Texas is 660-760 miles across, meaning our "asteroid" is somewhere between the size of Charon and Iapetus. Let's say Charon to be conservative, so we're looking at a mass of 1.6e21 kg. How large does our "rogue comet" need to be?

The maximum gravity assist occurs with a deflection angle of 180 degrees, meaning that the rogue comet would need to be retrograde with a periapsis at around 2.7 AU. Presumably if this was an interstellar comet they would have said that, so let's place its apoapsis at the farthest reaches of the Oort cloud, 200,000 AU away. That means its retrograde velocity at periapsis is -25.6 km/s.  To rob our "Texas-sized asteroid" of the largest possible velocity, the comet will need to reverse its velocity plus get a boost from the (new) velocity of the asteroid, a difference of 60.4 km/s. If the change in momentum of the asteroid is 7.8 km/s and the change in momentum of the comet is 60.4 km/s, then by conservation of momentum the mass of the comet is 2.1e20 kg, about twice the size of Enceladus.

At least you wouldn't have to worry about a future Giant Enceladus encounter, since this gravity assist would eject it from the solar system.

(Realistically, this would only be possible if both the "Texas-sized asteroid" and "rogue comet" were point masses. The gravity assist would be less efficient because they would be separated by their surfaces, meaning the "rogue comet" would likely need to be much, much larger.)

[kerbiloid]

Spoiler

  

4 hours ago, sevenperforce said:

antitinder

An antisocial antinetwork which prevents dates, unlike Tinder?

 

We can put a huge inflatable boxing glove behind the ship and let it be pushing the pusher plate by inflating/deflating.

(We could use an inflatable boot, but then we should replace the pusher plate with kicker plate.)

Edited December 1, 2020 by kerbiloid