NationStates Jolt Archive

Many people in here simply love to use C-fractional weapons in space. I mean, what can survive 10kilos of depleated uranium (or anything really) moving at 0.3C? 0.7C? Answer, not much. But this doesn't mean that attacks at a high percent of the speed of light are easy, economical, or even always useful. Several problems exist:

1: The most obvious problem (imo) is fuel. It takes a LOT of energy to get up to even 30% the speed of light. In fact, if you had a reactor->engine efficiency of 90% (which no one should even be near), it would take nearly 1.4 kilograms of deuterium/tritium to accelerate 1 kilogram to 0.3C...and that does NOT include the fuel itself. Tritium and deuterium are $$expensive$$, and this shows that to get to that velocity, you would need well over half (closer to 3/4ths) of your ship's mass to be pure fuel.

Then you have to slow down again. This means you have to more then double your fuel...because the fuel you use to slow down must be sped up in the first place. God help you if your ships have to go out, stop, turn around, come back, and then stop again just to do battle.

Of course, there are tricks to getting around this. Example: The Star Trek "inertialess" drive system...but all this does is make the ship seem less massive. It goes 0.3C, but doesn't have all that kinetic energy, and neither would it's weapons. Example2: Magic power-sources, like "zero-point energy", things that don't exist. If you do this, fully expect the other side to make up "magic technology" of it's own.

2: Another problem is one of relativity. If your going 0.3C towards a target, that target may as well be going 0.3C towards you. All you've done by accelerating is upping the odds for both sides. Anyone hit will die...except that your enemy didn't waste fuel doing this.

3: Yet another problem also has to do with relativity...time dialation. Really, at 0.3C, the effects are barely noticable...but they ARE noticable. The concept here is that the person who accelerated to C-fractional speeds didn't only waste tons of expensive fuel, but now experiances less time then those who didn't. That literally gives them less time to react.

4: Another problem is that of detection. It isn't hard to guess that a ship with engines on max and using high-energy magnetism to brush aside radiation is much easier to see on sensors then a ship that is barely moving. Which to you think is easier to target?

That targeting problem is especially true with the distances used in relativistic space combat. At 0.3C, your ship covers a 10light-second gap in just over 33 secnods. Exactly how far are your sensors good for?

Keep in mind that your sensors are also lagged. At 10 light-seconds, your seeing what happened 10 seconds ago in reality (and the person who accelerated to 0.3C will see those 10 seconds go by very fast, and at a higher frequency).


There are a lot more problems with relativistic velocities, but we'll leave it with those for now. Fuel, relative velocity, time dialation, and detection.

Just a note, you mentioned tritium/deuterium as not being fuel, but I think with the types of fusion engines many use, they would indeed be fuel. Although there would be the propellant, like hydrogen or some such, as well, which of course has its own problems.

Excellent post! Maybe now space battles will take more than a "whoever types in the largest percentage of C wins," but I'm not holding my breath..

Thank you... I don't know how people really can think they have projectile weapons travelling at .5c, let alone SHIPS travelling .5c on sublight drives. I mean, a sack of potatoes going .5C would do as much damage as a mile-wide meteor doing 1000 miles per hour.

I don't know why these people think .5C is at all realistic. My fastest most powerful Rail Cannon goes 120,000 m/s I think... and that is like .005c or something like that.


THe only thing I hate more than people saying they have engines/weapons that make things go .5c without FTL drives... is the people (Soviet Trasa) who think they can have their ships DODGE something going half the speed of light ;)

BTW, half the speed of light is around Mach 40,000... so... don't even try it.

Just a note, you mentioned tritium/deuterium as not being fuel, but I think with the types of fusion engines many use, they would indeed be fuel. Although there would be the propellant, like hydrogen or some such, as well, which of course has its own problems.

Excellent post! Maybe now space battles will take more than a "whoever types in the largest percentage of C wins," but I'm not holding my breath..

Where did I say that? Maybe a typo? I specifically mentioned deuterium and tritium because they are considered the ideal fuel for a fusion reaction. They are also both quite expensive.

But thanks.

Excellent. Someone with some sense.

I would never use c-frac weaponry. My ships have two kinds of weapons at this point--lasers and missiles. They come in various sizes, but still are reasonable simple.
My ships would never go that fast. They can accelrate at a maximum of 30G, and only with acceleration compensation provided through artificial gravity. That's for a fighter-sized hot rod. Anything with more mass accelerates at about 5G.

I also made a point of making sure all of my technology that requires technobabble was bought from people larger than myself.

~Independant Pluto

Good post.

I doubt it will help much, since those who most need to read it are:

A) Barely able to read to begin with,

B) Incapable of using reason or logic,

C) Completely awestruck at the pretty FX in their favorite TV shows/Movies and therefore immune to rational thought from others,

or

D) All of the above.

It should be noted, though, that at least one type of relativistic weapon is feasible: The laser, or particle cannon.

But those have other problems....

Which is why I like to stay away from space combat.

This has been a semi-humorous post.

It should be noted, though, that at least one type of relativistic weapon is feasible: The laser, or particle cannon.

But those have other problems....

Which is why I like to stay away from space combat.

This has been a semi-humorous post.if not for that last line, I'd have to flame your incompetence for not realizing we're talking about uber-Kinetic weaponry, and not energy...

Well... The fastest moving weapon I have is my missiles. Those are launched out of a launcher(which after the launch of the missile is rendered useless because of the energy and strain put on it from launching a missile at such high speeds). They cary fuel, but only to make course corrections.

My Gauss shells do move quite fast, but the barrels may explode, and the barrels must be replaced quite often.

Of course I am rarely in a space combat situation.

The highest speed of one of my missiles: .3c, with 50% of failure launch

The highest speed of one of my gauss cannons: .1c, with 30% of failure

Now on ships, I'm switching to plasma drives and have been using orion drives and accelerated ion drives(B5-tech).

I'm not a physics expert, mainly do to the fact I'm in the 8th grade, so... I'm learning. *wants to take physics, needs to take physics NOW*

C-Frac....

Blah...exactly why I don't try to be realistic with my ship's cannons...we use Polaron Disruptors... :lol:

What are Polaron Disruptors you ask? *Insert Star Trek Technobabble here*

It doesn't really matter to me though. I don't get in many wars anymore...and the tech I've got I've gotten through RP's about topics other than war. I don't simply say "Hey...I've got it" but still...it's not real...and I don't pretend it to be.

Well... The fastest moving weapon I have is my missiles. Those are launched out of a launcher(which after the launch of the missile is rendered useless because of the energy and strain put on it from launching a missile at such high speeds). They cary fuel, but only to make course corrections.

My Gauss shells do move quite fast, but the barrels may explode, and the barrels must be replaced quite often.

Of course I am rarely in a space combat situation.

The highest speed of one of my missiles: .3c, with 50% of failure launch

The highest speed of one of my gauss cannons: .1c, with 30% of failure

Now on ships, I'm switching to plasma drives and have been using orion drives and accelerated ion drives(B5-tech).

I'm not a physics expert, mainly do to the fact I'm in the 8th grade, so... I'm learning. *wants to take physics, needs to take physics NOW*And that is exactly what this guy is talking about. A missile going .3c... if it missed its target, it would have to go for a few million miles before it could come back around. Do you realize how fast .3c is? If you saw something going .3c, you couldn't tell it wasn't going the speed of light. And a .1c gauss cannon? holy crap! the force it would exhert on your ship to launch anything bigger than a soda can would be so much that you'd go into a chaotic spin!

OOC:ADK is only in the 8th grade??NO!! :D

The rail drivers mounted on my fighters fire projectiles at 10,000 m/s exiting the barrel.Super-capitol mass drivers exceed 650 m/s seeing as the projectile is much larger.

Well... The fastest moving weapon I have is my missiles. Those are launched out of a launcher(which after the launch of the missile is rendered useless because of the energy and strain put on it from launching a missile at such high speeds). They cary fuel, but only to make course corrections.

My Gauss shells do move quite fast, but the barrels may explode, and the barrels must be replaced quite often.

Of course I am rarely in a space combat situation.

The highest speed of one of my missiles: .3c, with 50% of failure launch

The highest speed of one of my gauss cannons: .1c, with 30% of failure

Now on ships, I'm switching to plasma drives and have been using orion drives and accelerated ion drives(B5-tech).

I'm not a physics expert, mainly do to the fact I'm in the 8th grade, so... I'm learning. *wants to take physics, needs to take physics NOW*And that is exactly what this guy is talking about. A missile going .3c... if it missed its target, it would have to go for a few million miles before it could come back around. Do you realize how fast .3c is? If you saw something going .3c, you couldn't tell it wasn't going the speed of light. And a .1c gauss cannon? holy crap! the force it would exhert on your ship to launch anything bigger than a soda can would be so much that you'd go into a chaotic spin!

That's what breaking thrusters and superfast calculations are for. A missile may use up all its fuel in making a course correction. But anyways, that's maximum speed. now that people have pointed out the incorrect things in my weapon systems I'll have upgrades to make them more 'economically' freindly.

Note that the standard shell a Khristian vessel uses is a 1" iron sphere.

Doesn't matter really, as we're devolping high-output energy weapons.

Hmm, good stuff, Wazzu. Another reason why haven't even tried space battles yet.

Wazzu got +1 Kudos!

heh, well yeah, if you're going to stand still and be a sitting target. My (Capsule Corporation's) ships are all in constant motion when in combat. Most of the weapons are spinal so that it can just plow forward and make itself a hard target to hit while dealing an incredible amount of force.

It should be noted, though, that at least one type of relativistic weapon is feasible: The laser, or particle cannon.

But those have other problems....

Which is why I like to stay away from space combat.

This has been a semi-humorous post.if not for that last line, I'd have to flame your incompetence for not realizing we're talking about uber-Kinetic weaponry, and not energy...
Ah, but I do realize that, hence adding the line.

Mewonders, though- what does the Holy Avenger of Cardboard say about Ion Accelerator Engines (i.e., ion engines that spit out particles at near-c), as long as we're on the topic of relativistic things?

It should be noted, though, that at least one type of relativistic weapon is feasible: The laser, or particle cannon.

But those have other problems....

Which is why I like to stay away from space combat.

This has been a semi-humorous post.if not for that last line, I'd have to flame your incompetence for not realizing we're talking about uber-Kinetic weaponry, and not energy...
Ah, but I do realize that, hence adding the line.

Mewonders, though- what does the Holy Avenger of Cardboard say about Ion Accelerator Engines (i.e., ion engines that spit out particles at near-c), as long as we're on the topic of relativistic things?particles CAN go near-c... BIG-@$$ starships can't (without FTL)

One thing to take into consideration is that not all ships use a direct propellant to move. For example, early Xanthalian FTL vessels used artificially created singularities to move at both light and sublight speeds (let's put aside for the moment how environmentally damaging and ill-concieved that was and just accept the example). Not to say you aren't right in saying that high sublight speed weapons are usually grossly impractical, but you do need to consider the fact that 'fuel' as you defined it does not always bear on the ability of a vessel (or even a weapon) to travel at certain speeds.

heh, well yeah, if you're going to stand still and be a sitting target. My (Capsule Corporation's) ships are all in constant motion when in combat. Most of the weapons are spinal so that it can just plow forward and make itself a hard target to hit while dealing an incredible amount of force.

Most of my weapons are on the edges and sides of my ships. I need to get access to a scanner.

C-Frac....

Blah...exactly why I don't try to be realistic with my ship's cannons...we use Polaron Disruptors... :lol:

What are Polaron Disruptors you ask? *Insert Star Trek Technobabble here*

It doesn't really matter to me though. I don't get in many wars anymore...and the tech I've got I've gotten through RP's about topics other than war. I don't simply say "Hey...I've got it" but still...it's not real...and I don't pretend it to be.

This is an important point I'd like to back. I do very much believe in using impossible technologies in NS. If you want to use something different, go for it. I tend to give a lot of credit for origionality, even if the idea wouldn't work in reality.

What I have little patience for is either pushing someting too far (ie. "wanking") or completely false understandings of physics. If you don't understand, say so rather then try to cover it up. You can do some research, or ask another player for help, or even just make completely new things up ("artistic license" as long as it is origional).

One or a few C-fractional weapons isn't really going to bother me. '50,000 iron balls going at 0.3C and you have half a second to respond' bothers me.


And that is exactly what this guy is talking about. A missile going .3c... if it missed its target, it would have to go for a few million miles before it could come back around. Do you realize how fast .3c is? If you saw something going .3c, you couldn't tell it wasn't going the speed of light. And a .1c gauss cannon? holy crap! the force it would exhert on your ship to launch anything bigger than a soda can would be so much that you'd go into a chaotic spin!

Actually, I was talking about entire ships boosting to 0.3C. Though rail/gauss guns certainly wouldn't be able to manage it either. An ICBM sized missile with a fusion engine probably could manage it, but that would be a very expensive missile (and as you pointed out, would not be able to turn back).


heh, well yeah, if you're going to stand still and be a sitting target. My (Capsule Corporation's) ships are all in constant motion when in combat. Most of the weapons are spinal so that it can just plow forward and make itself a hard target to hit while dealing an incredible amount of force.

What? Spinal something? That didn't make any sense.

It should be noted, though, that at least one type of relativistic weapon is feasible: The laser, or particle cannon.

But those have other problems....

Which is why I like to stay away from space combat.

This has been a semi-humorous post.if not for that last line, I'd have to flame your incompetence for not realizing we're talking about uber-Kinetic weaponry, and not energy...
Ah, but I do realize that, hence adding the line.

Mewonders, though- what does the Holy Avenger of Cardboard say about Ion Accelerator Engines (i.e., ion engines that spit out particles at near-c), as long as we're on the topic of relativistic things?

The Cardboard Avenger says, "awsome idea."

Actually, the idea is fairly simple. Standard ion engine (as NASA uses) putting ions into a short particle accelerator...or even something as simple as a couple of cyclotrons (2 to cancle out any spin caused by the acceleration).

Wazzu used to use a mix of technologies that included such a thing (actually, it still does on it's shuttles).

And advanced "thermite" (metal-oxide/metal reaction, very hot) fuel (suspended in a liquid of catalysts) was burned (to get as much energy from the carried fuel as possible) and the resultant further heated to its ionization point...then accelerated out the back in much the same way as a particle accelerator. A simple fission battery provided more then enough electricity.

In the end, you get a drive with more efficiency then a traditional chemical drive, and more thrust then a typical plasma or ion drive.

So, a very good idea. :)

C-Frac....

Blah...exactly why I don't try to be realistic with my ship's cannons...we use Polaron Disruptors... :lol:

What are Polaron Disruptors you ask? *Insert Star Trek Technobabble here*

It doesn't really matter to me though. I don't get in many wars anymore...and the tech I've got I've gotten through RP's about topics other than war. I don't simply say "Hey...I've got it" but still...it's not real...and I don't pretend it to be.

This is an important point I'd like to back. I do very much believe in using impossible technologies in NS. If you want to use something different, go for it. I tend to give a lot of credit for origionality, even if the idea wouldn't work in reality.

What I have little patience for is either pushing someting too far (ie. "wanking") or completely false understandings of physics. If you don't understand, say so rather then try to cover it up. You can do some research, or ask another player for help, or even just make completely new things up ("artistic license" as long as it is origional).

One or a few C-fractional weapons isn't really going to bother me. '50,000 iron balls going at 0.3C and you have half a second to respond' bothers me.



I come up with most of my stuff on my own...I only use pictures of other things...not the names/stats/etc.

I don't "wank," although my nation is RPed in the far future, meaning that some of my tech is rather out there. I know physics, I just choose not to use them for all things. Some parts of my ships and stuff follow physics to the "T", others completely abandon them. I readily admit this fact and I only post science if it is indeed real science.

Also, 99% of my starship weaponry is energy based...so I don't have much of a problem with C-Frac...and all of my starships are FTL capable.

One thing to take into consideration is that not all ships use a direct propellant to move. For example, early Xanthalian FTL vessels used artificially created singularities to move at both light and sublight speeds (let's put aside for the moment how environmentally damaging and ill-concieved that was and just accept the example). Not to say you aren't right in saying that high sublight speed weapons are usually grossly impractical, but you do need to consider the fact that 'fuel' as you defined it does not always bear on the ability of a vessel (or even a weapon) to travel at certain speeds.

"Fuel" as I defined it is just an energy source.

It is a well known fact that Xanthalian vessels do not obey the law of conservation of energy (or any other scientific law, principle, or equation).

The calculation is simple. At 100% efficiency (does not account for energy lost to continue the reaction, to weapons, life-support, little inefficiencies, etc), 1kg of deuterium/tritium provides 2.58946 x 10^15 Joules of energy (this comes from E=mc^2).

You can plug that straight into the equation for kinetic energy, KE=0.5mv^2.

In my first post, I assumed 90% of your reactor energy going directly into forward movement, and that is really really high.

Antimatter could not provide this much because it must be contained as a gas (much higher in volume if lower in mass then liquid hydrogen)...you'd have a HUGE ship, most of it containing antimatter with a giant magnetic field which ate most of the energy gained from the reactor.

Zero-point energy simply does not exist (it is a failed-science induced fantasy much like cold fusion and perpetual motion).

You COULD, theoretically, get energy from a black hole...but black holes have a lot of mass. Could you imagine moving something 3 times (or more) more massive then our sun? Black holes don't really provide that much energy.

Xanthalian ships use "magic" technology, which would be OK (as even Menelmacar, Melkor_Unchained, Sunset, Steel Butterfly, and even Wazzu use it) except that it is overdone. Everything is magically cheap, plentiful, and the most powerful/fastest/reliable/etc in existance.

Anyway, back to the fuel...thats simply energy gained from fusion put directly into forward motion. It doesn't matter how you do it, only that energy is conserved.

I come up with most of my stuff on my own...I only use pictures of other things...not the names/stats/etc.

I don't "wank," although my nation is RPed in the far future, meaning that some of my tech is rather out there. I know physics, I just choose not to use them for all things. Some parts of my ships and stuff follow physics to the "T", others completely abandon them. I readily admit this fact and I only post science if it is indeed real science.

Also, 99% of my starship weaponry is energy based...so I don't have much of a problem with C-Frac...and all of my starships are FTL capable.

Which is probably why I don't remember ever saying stuff about your technology. :)

I come up with most of my stuff on my own...I only use pictures of other things...not the names/stats/etc.

I don't "wank," although my nation is RPed in the far future, meaning that some of my tech is rather out there. I know physics, I just choose not to use them for all things. Some parts of my ships and stuff follow physics to the "T", others completely abandon them. I readily admit this fact and I only post science if it is indeed real science.

Also, 99% of my starship weaponry is energy based...so I don't have much of a problem with C-Frac...and all of my starships are FTL capable.

Which is probably why I don't remember ever saying stuff about your technology. :)

:wink: Can't say I remember either :lol:

How about this: My future tech puppet uses "Gauss Weapons" that strike the relatavistic velocities you speak of with horror, but they are in reality more along the lines of particle accelerators, firing not shells but bursts of particles. (Protons can go those speeds in modern accelerators, btw.)

The cardboard avenger strikes again. Just more reason why I should stay grounded. Too bad you weren't around to say this when I needed you to...... :wink:

Xanthalian ships use "magic" technology, which would be OK (as even Menelmacar, Melkor_Unchained, Sunset, Steel Butterfly, and even Wazzu use it) except that it is overdone. Everything is magically cheap, plentiful, and the most powerful/fastest/reliable/etc in existance.I really wish people would stop saying that... It's not that wonderful. Everything I build has a weakness, I make sure of that.

That was as Xanthal, by the way...

To get a ship going anywhere near a fraction of the speed of light, you'd need to spend an awfully long time accelerating. (I'm not sure how long though).

I am sure, however, of some basic physics principles. Namely, Newton's second law, which states that for every action, there is an equal and opposite reaction.

So, for firing rail guns on space ships or something like that; the force that causes the round to come flying out ALSO pushes the ship backwards, opposite the direction of the round.

Momentum=mass x velocity

.3C is roughly 259,818 meters a second, and,assuming the round is 10 kg, the round has a momentum of 2,598,180 kg m/s.

Since an equal force is exerted on the ship, which we'll say has a mass of 50,000 kg, and
(2,598,180 kg m/s)/(50,000 kg)=52 m/s

Thus, the ship would move backwards at a rate of 52 m/s. Obviuosly, repeated firing of such a rail gun would cause the ship to move backwards very fast.

If you do happen upon someone with some way of firing a rail gun that fast, challenge them to a duel, and position them in front of a black hole. Problem solved. :D

Holy Empire of Komdor
Ministry of Physics

Wazzu, what do you think of Dontgonearthere's fleet of 24-mile-long Planet destroyer psycho cruisers?

Wazzu, what do you think of Dontgonearthere's fleet of 24-mile-long Planet destroyer psycho cruisers?

Never heard of them....

Wazzu great info as always, and Spinal weapions atleast in the term I know is mostly fowarad facing think of the ion and assult frigates I have. Al tho he may be speeking of somthing compleatly diffrent. By the looks of things I realy need tu upgrade some systems I seem to be out mached in way of speed of both ships and guns.

Wazzu, what do you think of Dontgonearthere's fleet of 24-mile-long Planet destroyer psycho cruisers?

Never heard of them....

Link to DGNT's 25-mile long ships: http://www.nationstates.net/forum/viewtopic.php?t=61956&highlight=

Wazzu great info as always, and Spinal weapions atleast in the term I know is mostly fowarad facing think of the ion and assult frigates I have. Al tho he may be speeking of somthing compleatly diffrent. By the looks of things I realy need tu upgrade some systems I seem to be out mached in way of speed of both ships and guns.Yeah, look at the ship in my sig... most of the power weapons are forward-only.

http://www.bateshome.com/jordan/zdf.jpg (http://www.nationstates.net/forum/viewtopic.php?t=93882)

Well glad we got that cleared up.... well off to feed my need for EVE.

Wazzu, what do you think of Dontgonearthere's fleet of 24-mile-long Planet destroyer psycho cruisers?

Never heard of them....

Link to DGNT's 25-mile long ships: http://www.nationstates.net/forum/viewtopic.php?t=61956&highlight=

Well, lets see.

25 miles long (31,250m)
3 miles wide (3,750m)
1 mile tall (1,250m)
Assume it is a box (for simplicity)
146,484,375,000 cubic meters
US $50 trillian

0.0029 dollars per cubic meter.

A third of a penny per cubic meter.

That sounds like cardboard to me.

I wouldn't want to be one of the (likely uneducated and oblivious) 25,000,000 people to crew that ship!!! And I mean, talking about bureaucracy wasting money! Hell, if that ship hit a peice of debris.... And can you imagine the damage weapons would do inside?

I wonder what the computers are made of...old atari 2400s? Do they even have those?

Komdor, care to make a mass estimate on that much cardboard and see how fast an asteroid would fling it backwards? *grin* Gotta love momentum.

Wazzu great info as always, and Spinal weapions atleast in the term I know is mostly fowarad facing think of the ion and assult frigates I have. Al tho he may be speeking of somthing compleatly diffrent. By the looks of things I realy need tu upgrade some systems I seem to be out mached in way of speed of both ships and guns.

Ahhh, thanks.

Though forward firing weapons would still have a lever arm (unless they go directly through the center of gravity), they would still produce an unwanted torque.

This shouldn't be too much of a problem for most ships...except perhaps those that cost less then a penny per cubic meter. *snicker*giggle*cough*

I'm sure you can get your ships going well, you've been off NS for a while so it only makes sense that your ships have gotten better in that time.

WHOOPS! Did that wrong. It is dollars/m^3, not the other way around.

That comes out to $341.33 per cubic meter, still awfully low. Wazzu's largest ship costs 687 times as much per cubic meter.

I'd still call those big ships "cardboard"...MAYBE cardboard/styrofoam/Elmer's glue composit. :)

WHOOPS! Did that wrong. It is dollars/m^3, not the other way around.

That comes out to $341.33 per cubic meter, still awfully low. Wazzu's largest ship costs 687 times as much per cubic meter.

I'd still call those big ships "cardboard"...MAYBE cardboard/styrofoam/Elmer's glue composit. :)well here's a decent question, how did you come up with your numbers? Although I do agree with your point... just wondering, for future ref.

The Cardboard Avenger says, "awsome idea."

Actually, the idea is fairly simple. Standard ion engine (as NASA uses) putting ions into a short particle accelerator...or even something as simple as a couple of cyclotrons (2 to cancle out any spin caused by the acceleration).

Wazzu used to use a mix of technologies that included such a thing (actually, it still does on it's shuttles).

And advanced "thermite" (metal-oxide/metal reaction, very hot) fuel (suspended in a liquid of catalysts) was burned (to get as much energy from the carried fuel as possible) and the resultant further heated to its ionization point...then accelerated out the back in much the same way as a particle accelerator. A simple fission battery provided more then enough electricity.

In the end, you get a drive with more efficiency then a traditional chemical drive, and more thrust then a typical plasma or ion drive.

So, a very good idea. :)
Yay! Now I just have to work out my maximum possible acceleration & speed... cuts down my list of questionable technologies to 1! (Does using Metastable metallic hydrogen as a battery/fuel source warrant allowances for artistic license?)

You COULD, theoretically, get energy from a black hole...but black holes have a lot of mass. Could you imagine moving something 3 times (or more) more massive then our sun? Black holes don't really provide that much energy.
I haven't bothered to actually work out the stats for what follows, as I pretty much just shamelessly stole it from Arthur Clarke, but how's about a micro black hole (only a few tons of mass) kept alive by a small but stead stream of hydrogen, and held in place by a magnetic bottle? The idea is that when the chamber is flooded with hydrogen, the resulting x-ray bursts from particles falling in would superheat the rest and force it out the back and uberhigh speed. When not used as an engine, it could be a high-efficiency matter-to-energy converter (assuming you have high-efficiency photovoltaics in the x-ray range.)

WHOOPS! Did that wrong. It is dollars/m^3, not the other way around.

That comes out to $341.33 per cubic meter, still awfully low. Wazzu's largest ship costs 687 times as much per cubic meter.

I'd still call those big ships "cardboard"...MAYBE cardboard/styrofoam/Elmer's glue composit. :)well here's a decent question, how did you come up with your numbers? Although I do agree with your point... just wondering, for future ref.

Convert miles to meters for length, width, height.

Assume it is a box.

Multiply length, width, height for total volume (in m^3).

Devide $50 trillian by the volume. Dollars/meters^3. So $341.33 per cubic meter.

And remember, thats not just for the materials used, but all the "advanced" technology, the cost of getting those materials to space, and the cost of paying and supporting all the dock workers in space in order to build the thing.


Yay! Now I just have to work out my maximum possible acceleration & speed... cuts down my list of questionable technologies to 1! (Does using Metastable metallic hydrogen as a battery/fuel source warrant allowances for artistic license?)

Metastable? Metallic hydrogen is stable as long as you have it under enough pressure. Not sure how it could be a battery, but it does seem like a good way to condense fuel. If you can think of a good reason/way to keep it under that much pressure, then sure, it warrants artistic license.

NOTE: You may want to talk to Sunset.

I haven't bothered to actually work out the stats for what follows, as I pretty much just shamelessly stole it from Arthur Clarke, but how's about a micro black hole (only a few tons of mass) kept alive by a small but stead stream of hydrogen, and held in place by a magnetic bottle? The idea is that when the chamber is flooded with hydrogen, the resulting x-ray bursts from particles falling in would superheat the rest and force it out the back and uberhigh speed. When not used as an engine, it could be a high-efficiency matter-to-energy converter (assuming you have high-efficiency photovoltaics in the x-ray range.)

photovoltaics don't work in the x-ray range, the frequency is too high, but there may be another way to get that energy.

But micro-black holes? I don't know enough about that theory. I'd imagine they would need a certain minimum mass (like that of a star) to remain a black hole, but I don't know.

People have often wondered if CERN could create a micro-black hole, but all theory has said it would not last...it would not have the mass to.

Lastly, I am not sure how effective it would be to use the X-ray bursts to accelerate hydrogen away from the black hole.

Lets just say, "I don't know." It would take some research to find out. Go do some. :) And good luck.

Yay! Now I just have to work out my maximum possible acceleration & speed... cuts down my list of questionable technologies to 1! (Does using Metastable metallic hydrogen as a battery/fuel source warrant allowances for artistic license?)

Metastable? Metallic hydrogen is stable as long as you have it under enough pressure. Not sure how it could be a battery, but it does seem like a good way to condense fuel. If you can think of a good reason/way to keep it under that much pressure, then sure, it warrants artistic license.

NOTE: You may want to talk to Sunset.

Metastable metallic hydrogen is a so-far theoretical form of hydrogen that would remain metallic at low pressure. I found out about it when researching space elevators (it was suggested as a possible tether material, as it's supposed to be several times lighter and stronger than aluminum). I've avoided using it for anything other than fuel storage so far, though, since I wasn't sure if it's close enough to reality. But now I'm getting this thread entirely off-topic. I shall go create my own.

There are much larger problems with high c-frac weapons then those already mentioned. The energy quantities required may be impractile, but they are not physically impossible. For example, the Saturn V launch for applo 11 in 1969 used 8% of the worlds annual energy consumption in just a few minutes. even if we assume a souce of "free" energy we still have massive problems to overcome.

Start with basic physics and use these equations:
v = at (Speed equals acceleration * time)
F = ma (Force equals mass * acceleration)
s = 1/2at^2 (distance covered is half acceleration by time squared)

To accelerate an object to 100 m/s at 1g would take ten seconds
(100m/s is about 200mph)

To accelerate to 259,818 m/s (.3c) would take 25981 seconds or little over 7 hours.

The distance covered would be 3,370,000 kilometers (about the distance between the earth and the moon). That is a pretty long gun barrel by any standards.

Yes you could accelerate faster, using 10g you would take 2598 seconds or 43 minutes, and only need a gun barrel 337,000 kilometers (200,000 miles) long.

Bust up to 100g sustained acceleration and it would take 260 seconds (4 minutes) and your gun barrel would be only 33,000 kilometers (20,000 miles) long.

But, big but here, at 100g, iron would start to deform as would most metals. If there was even the slightest leak of energy from the acceleration, the "bullet" would be totally vapourised as would your 20,000 mile long gun barrel.

Biggest but of all, and the best reason not to use them, it would not significantly damage its target. It would punch straight through without slowing down. There would be no significant energy transfer to the target because any meterial it hit could simply not pass on the forces involved. (Think high powered rifle into an empty paper bag, it would punch through, but it would not even knock it over). Any space craft has got to have automatic puncture repair, and it is no more complicated then a car tyre. There is a slim chance that it would hit a crewman, but the risk would be the same as for micro-meteorites.

*bump*