Newtonian Aurora

[Din182]

It's called thrusters.  My definition is based upon the primary means of giving them velocity, not on being unguided.
Unguided kinetics are very impractical.  See http://www.rocketpunk-manifesto.com/2010/11/home-away-from-home.html?showComment=1289267698643#c759139992445967698 for more details.

Yes, but the railgun ammo is only going to be a few kilograms. Not really enough to put on thrusters, at least not without greatly increasing the size, which will slow it down significantly.

[bean]

You could fit a halfway-decent guidance system and some thrusters on something that size today.  We have guided mortar rounds in that size range, and all the machinery isn't going to cut lethality at all.  Aurora is more advanced, and if you look at the link, you'll see why unguided kinetics are a bad idea.

[Elouda]

You could fit a halfway-decent guidance system and some thrusters on something that size today.  We have guided mortar rounds in that size range, and all the machinery isn't going to cut lethality at all.  Aurora is more advanced, and if you look at the link, you'll see why unguided kinetics are a bad idea.

Thats because mortar rounds only need a simple system such as fins to guide them, whereas a kinetic in space requires an engine and delta-v reserve.

EDIT: Also, your article deals with hitting things at rather extreme ranges; 2 minutes is a long time. I expect kinetics will be faster than 'realistic' in Newtonian Aurora for the sake of gameplay, and as a result the evasion window will be smaller. Also remember Aurora is 2D, so its easier to 'bracket' targets with kinetics. Again, not realistic, but as long as the gameplay is fun and self-consistent, who cares. I trust Steve will get it right.

[Din182]

You will need some sort of fuel. And that will take up most of the space I was talking about earlier. I don't think that guided projectiles will be worth it until you get some extremely powerful and efficient engines.

[bean]

You will need some sort of fuel. And that will take up most of the space I was talking about earlier. I don't think that guided projectiles will be worth it until you get some extremely powerful and efficient engines.

And what do you think Aurora's engines count as?

My point is simple.  Even a very low-powered guidance round is vastly more effective then a non-guided round.  I'll do some math on this.
Let's say a projectile has 1G acceleration (10 m/s2) and 100 m/s of delta-V, with a flight time of 10 seconds.  During that time, it can deflect in a circle with a radius of 500 meters.  Farther, let's say that the ship we're facing has a cross-section of 100 m.  (I'm going to work both as lines, because this is Aurora).  The guided round has a total target cross-section of 1000 m, and it's actually more like 1100 because of the size of the ship.  The unguided round only has 100 m, so a guided round is 11 times as effective.  For a 10-second flight time.  And I don't think it would be serious trouble to build a guided round with 100 m/s of delta-V, and 1G acceleration, along with a basic guidance system.
11 times.  Remember that.  The picture gets even worse in 3D.

[ardem]

This has been a common science fiction idea for years (for example Charles Sheffield's stuff).  The problem is in the paragraphs about 1/3 of the way down the 2nd page - if you can pull energy from the vacuum, then that means the vacuum is unstable and can go into a different state, where the laws of physics would be different and we'd all die.


As an example of this, think about two populations of (fresh water) fish - "A" that's living in water that's 5 degrees C and "B" that's living in water that's -5C.  In both cases, there's thermal energy in the water.  In case "A" the fish can try to extract that energy by rearranging the water into ice.  The problem is this doesn't work - the "water" state is the stable one.  In case "B", it will work - you'll get energy out of the water by turning it into ice.  The problem is that water likes (energetically) to be in the "ice" state at -5C, and the ice crystal you just made will grow until the whole pond is made out of ice and the fish die because the physical properties of water are very different from those of ice.  If you say "vaccuum" everywhere I said "water", then you've got the argument on the 2nd page....

CAVEATS:
1)  Experts will notice that I was being a little fast and loose about energy vs. free energy above.  The general argument remains the same, though.
2)  There's always the very small chance that some of what we think are very basic physical principles (like the 2nd law of thermodynamics) might not apply at these small scales/high energies.  If so, something weird might come out of it.
3)  If the vacuum is "choppy" (think waves on water), then there might be a way to extract energy from the chop.  I suspect it would be difficult to get much out, though.

John

Scientist also originally said that breaking the speed barrier was an impossibility. Flight was impossible. And nothing could move faster then light. The word 'nothing' was the optimum word here, but there is a possibility that something does. Scientist change there reasons and definitions the more they understand the more they learn they do not understand.

What if they do succeed and it doesn't destroy the universe. Then science changes again. That why I smile a naysayers including no in space stealth people. Human do not hold the mysteries of the universe and I doubt we ever will. I believe the universe will have an infinite amount of mysteries to answer.

I was reading another article a theory about creating an optical bubble, to hide things. IR is just another form of light transmission. I think "never say never" cause when you do someone always ends up with egg on there face.

[bean]

Scientist also originally said that breaking the speed barrier was an impossibility.

Not as a physical impossiblity.  As an engineering one.  And not by the time they started to get good data.

Flight was impossible.

No, manned flight was impossible.  And nobody said it was a scientific impossibility, either.

And nothing could move faster then light.

That hasn't been proved yet, and I for one am highly skeptical.  The probability that there's some error is still very much present.

The word 'nothing' was the optimum word here, but there is a possibility that something does. Scientist change there reasons and definitions the more they understand the more they learn they do not understand.

What if they do succeed and it doesn't destroy the universe. Then science changes again. That why I smile a naysayers including no in space stealth people. Human do not hold the mysteries of the universe and I doubt we ever will. I believe the universe will have an infinite amount of mysteries to answer.

I was reading another article a theory about creating an optical bubble, to hide things. IR is just another form of light transmission. I think "never say never" cause when you do someone always ends up with egg on there face.

I can say that under our current understanding of how the universe works, the law of conservation of energy will hold.  If it doesn't, then everything goes out the window.
Read this link before we go any farther.  http://www.projectrho.com/rocket/respectscience.php
Think it over carefully, and remember that just because it might be possible doesn't mean it is.

[jseah]

Let's say a projectile has 1G acceleration (10 m/s2) and 100 m/s of delta-V, with a flight time of 10 seconds. 

You see?  That's why I wanted railguns that could launch stuff, not just mass packets. 

Railgun launched missile is what you are talking about there. 


Then again, there might also be a problem about launching a fusion torch drive at a humoungous accelerations a railgun imparts. 

[sloanjh]

Scientist also originally said that breaking the speed barrier was an impossibility. Flight was impossible. And nothing could move faster then light. The word 'nothing' was the optimum word here, but there is a possibility that something does. Scientist change there reasons and definitions the more they understand the more they learn they do not understand.

What if they do succeed and it doesn't destroy the universe. Then science changes again. That why I smile a naysayers including no in space stealth people. Human do not hold the mysteries of the universe and I doubt we ever will. I believe the universe will have an infinite amount of mysteries to answer.

I was reading another article a theory about creating an optical bubble, to hide things. IR is just another form of light transmission. I think "never say never" cause when you do someone always ends up with egg on there face.

Ummm I didn't (intend to) say never - that's what caveat number 2 was about.  That being said, given everything we know today (including quantum field theory, which is where the vacuum energy stuff comes from) and applying the correspondence principle, the odds of it being possible to suck energy from vacuum fluctuations in a non-catastrophic way are VERY small.  Something very fundamental, like the 2nd law, would have to be violated.

Two more things:

1)  Science (scientific models, actually) doesn't change; it extends the accuracy and extent of the phenomena it describes - this is the correspondence principle. http://en.wikipedia.org/wiki/Correspondence_principle (note that the wikipedia article isn't very good - it leads off applying the principle only to quantum mechanics when in fact it applys to all scientific models).

2)  As an amusing side note, quantum field theory predicts that if tachyons (particles which travel faster than light) exist then the vacuum is unstable and we're back in the "different state" catastrophe situation.

John

[UnLimiTeD]

One can assume that a missile, the engine and fuel, have less mass than a solid projectile of the same size, thus, a guided projectile would require a larger caliber railgun to fire a projectile of the same kinetic energy.
Additionally, given other factors of space combat, there is a great range of possibilities affecting the efficiency of weapons.
If your ship is going 150k anyways, the 70 you might get from the railgun could be substituted for slightly larger projectiles, and you'd be directly firing guided missiles.
Especially on ranges that have 30+ seconds slight time anyways.
However, one could assume to use the maneuvering engines to give additional thrust, yet still the gain would be too marginal.
If, instead, the range of the engagement is within just a few hundred kilometers, a guided projectile does not measurably increase the hitrate, while reducing the firerate(or damage output).
And wouldn't a defensive nuke be able to blind/damage a guided projectile, thus eliminating the advantage?
What about electronic warfare/decoys to simulate a ship shortly, maybe not able to confuse a ship-board sensor, but the small homing device of the projectile? Direct guidance might result in delay and thus give up part of the advantage, while directed ECM will food the guidance of such a small projectile that will have to be either conductive, and thus magnetic, allowing pulse magnet fields to alter it's course and damage electronics, or not, in which case it's not shielded from a medium-powered, and a lot faster-fireing, microwave laser to take it out.

Sure, these a re all very small caveats, but;
Given that a guided bomb is quite probably several hundred times more expensive than a chunk of metal, and more prone to failure, it raises the question if it wouldn't be drastically more economic, if less effective, to just mount more guns and fire a storm of standard pellets. Or leave out the railgun in favor of boxlaunchers.^^

[Steve Walmsley (OP)]

Wait.  Are kinetics (coilguns, railguns, etc.) going to be unguided, or just have minimal tracking capability?

At the moment they are unguided. Guided kinetics will be missiles with a shrapnel warhead, or maybe a solid warhead. I am sure I will include some type of hybrid missile-railgun combination at some point.

Steve

[Steve Walmsley (OP)]

Given that a guided bomb is quite probably several hundred times more expensive than a chunk of metal, and more prone to failure, it raises the question if it wouldn't be drastically more economic, if less effective, to just mount more guns and fire a storm of standard pellets. Or leave out the railgun in favor of boxlaunchers.^^

Some form of lower velocity shotgun type weapon is definitely a possibility. In fact, throwing a large rock out the back of the ship into the path of a fast-moving enemy ship could be effective given the right circumstances. Different weapon types are going to be effective in different situations and in some of those situations high tech vs low tech may be far less of an advantage than in standard Aurora.

Steve

[Steve Walmsley (OP)]

It's worth considering that its entirely possible that ships may be moving faster than the kinetic projectiles and the closing speed is what determines damage, rather than just the speed of the projectile. The chance of avoidance may also be more affected by the ship speed than that of the projectile. The railgun may be used just to get the projectile into the path of a ship, rather than shooting directly at it.

I am considering the idea of a "debris cloud" (name not definite) which would be an area of space with a given diameter, that has x number of objects with y size. If you fly through the cloud then I will calculate the chance of you striking one of those objects and the damage will be based on the size of the object and the impact speed. That debris cloud could also be moving and expanding at the same time. This is probably how the shrapnel warhead will be modeled. I may also handle nebulae in the same way, with the whole system as a debris cloud of dust particles with the chance of occasional larger objects. Shields will work but will be degraded by constant impacts. Or you can move slow enough that the vast majority of impacts will be below the armour threshold.

Steve

[bean]

Why does everyone keep calling these things missiles?  It's far more akin to a guided artillery shell. 
Several things to keep in mind:
1. My example above was a minimal example.  Doubling the acceleration and delta-V makes it 21 times as effective, and so on.
2. We're dealing with the far future, and fairly rudimentary guidance systems.  The system from the original sidewinder missile should work, with proper modifications.  That's pretty cheap.
3. The mass of the engine and guidance system does not subtract from lethality.  They hit with the rest of the projectile, and do damage.  And there's not a lot of remass used at the delta-Vs I've mentioned, even with cold gas.

[Mel Vixen]

I guess you guys discuss using the casimir effect to "create" energy. Actually it is experimentally proven (see this article on TechReview) that you can turn a virtual photon into a real one. ATM you put more energy into then you get out thought. If it can used to "produce" power *shrugs* no clue ask the guys who did the experiment.