Ships Drives

[Reynard]

"Sorry, my mind went elsewhere - long day. I meant lightspeed lag. Your passive sensors would tell you a tiny instant before impact that something is going on, your active sensors wouldn't do much better if the projectile is moving nearly as fast as the fastest signal. You could use an X-boat though, stationed in a monitor system one or two parsecs in front of mainworld to warn them that something fast is coming their way. As for intercepting - well, a laser moves at c, fire control taken into account - slightly slower. Too slow for a RKI meaning business."

Monitor system one or two parsecs away? Take me back a moment, are we taking about an object being jumped from another star system with a built up velocity that will exit at the destination just before impact? Does the X-boat with lousy sensors get lucky to spot such an object? I take it the boat jumps back to the target destination and gives a light speed warning just before the weapon hits.

It sounds like they are expecting such an attack so station ships, lots of ships, with real sensors in nearby jumpable systems as a picket patrols. Station squadrons to intercept such attempts before it jumps to the target. Have scouts patrolling likely systems that could be routes to the target and get the word to the squadrons in systems nearest the target to prepare to intercept. Unless a LOT of space has been made for fuel akin to a large hollow ball with engines, the ship will need somehow to refuel other than skimming. Rock bombs are expensive already and I doubt they're build with the best sensors, computers or evasive capacities. They are straight-line bulling through a system to a jump point while building optimal speed. They are really big targets either computer controlled or with a suicide crew only concerned with the jump so all thrust to acceleration so no evasive action and probably poor skill sets. Moving in such predictable courses could be a Boon.

This might explain, after thousands of years, why no one drops rocks with engines.

 

[rust2]

Many of Traveller's inhabited planets could be made uninhabitable with much less complex and expensive means than c-rocks. Some of the uninhabitable red zones doubtless are the results of accidents, like Ganulph, or of intentional planetwide destruction. No need to worry much about c-rocks, there are so many other and far more probable dangers planetary security forces have to prepare for. :evil:

 

[Reynard]

Please please tell me what SFRPGs you play regularly (obviously not Traveller) that describes in such detail as if the players were actually their character. A referee gets as descriptive as his imagination allows without memorizing textbooks of every sort. A scene is set, situation is elaborated in details ONLY needed to give players enough to make useful decisions. Players may ask for more detail whether it helps or not and the referee decides what may be created to further aid in a decision.
REF: The impact of the missile is causing the maneuver engine to become erratic (M-drive critical severity 2). You're having a hard time keeping the ship steady and losing maneuver thrust. What do you do?
Commander: Engineering, get a tech on the drive now! Pilot, open range and keep then guessing.
Pilot: Doing the best I can! [Open range, evasive action]
Engineer: I look over the system and begin emergency repair [Repair system].
They don't need to know every nut, bolt, valve and circuit and don't care to know. Slows thing down to DULL BEYOND BELIEF. Game plays on and people have fun. They florify the scene to dress it up but they don't try to pretend to have doctorates in All Things Real.

Again, tell us what game have such amazing detail? And I have a LOT of SFRPGs.

 

[theodis]

Monitor system one or two parsecs away? Take me back a moment, are we taking about an object being jumped from another star system with a built up velocity that will exit at the destination just before impact?

No. We're talking about a small nickel-iron asteroid, approx. 4-5m across, tossed and aimed from another star system at .99c

Unless a LOT of space has been made for fuel akin to a large hollow ball with engines, the ship will need somehow to refuel other than skimming.

The object in question would weigh about 400 tons. So one puny thruster plate alone could accelerate it at .1g for 10 years, reaching .99c. This thruster plate would constantly draw 1MW and the energy source needs reactor fuel for 10 years. Attainable without much sweat in the Traveller universe.

They are really big targets either computer controlled or with a suicide crew only concerned with the jump so all thrust to acceleration so no evasive action and probably poor skill sets. Moving in such predictable courses could be a Boon.

Again, no. They are small targets moving at speeds that make any attempt of intercepting them (short of a planetary whipple shield capable of withstanding planet crushing energies) utterly futile.

 

[Tenacious-Techhunter]

Reynard, as you describe it, a character whose job it is to interact with technology is only capable of repairing things; he’s not capable of coming up with creative solutions to problems, because there’s no detail underneath to interact with.

What if your ship’s engineer wants to try using a laser pistol cartridge in lieu of a proper capacitor to smooth out the flow of power to the damaged engine?

1. We already know that a laser pistol cartridge stores power, so at least that much is sound
2. Assuming it’s known that it’s a rechargeable type, and not a disposable one, we know it can be charged
3. But can it be charged and discharged at the required rate?
4. And does it have enough capacity to prevent the brownouts it’s being put there to stop?
5. And how gracefully is it going to fail?

In order to tell the difference between whether this is a clever idea that has some merit, a totally nonviable cockamamie scheme that could never work, and the interesting in-between where the players are properly challenged, players and GMs need a lot more hard info!

 

[Sigtrygg]

A reader isn’t told by Larry Niven to survive in his universe. It’s the pre-written, fore-ordained trials and tribulations of the characters in the book that make it entertaining.

You mustn't have a copy of the Ringworld rpg - I have and it's great.

Tabletop RPG isn’t the same thing as works of fiction. Players and GMs have to depend on the information given to them, and have to form plans based on that information. That’s not something a member of a work of fiction’s audience has to do! Because the role of information is different between the two mediums, fiction authors can get away with a lot of crap that Tabletop RPG authors simply can’t. Information in a Tabletop RPG has to be actionable, because, at the spur of the moment, a player may come up with a clever plan, one that the GM was not expecting, and when the GM, desperate for some plausible constraints for that plan, turns to the book, all he currently gets is flowery language. If, instead, that technology was given some practical constraints to begin with, the GM and the player would at least have some common ground with which to put that plan into action. Instead, just like the Game Developer threw their hands into the air, the GM does.

When you play a fantasy rag do you need to know how the magic works?

 

[phavoc]

You can’t use badly written fiction to justify other parts of badly written fiction. Instead, you can write good fiction that doesn’t need justification. The solution to this problem is to constrain the performance of Reactionless Drives somehow so that they simply can’t perform at all well particularly close to C.

Who is using fiction? It's reality! The meteor impact crater that makes up much of the western portion of the Gulf of Mexico, the Tskunga meteor, to name just a few. I'm assuming you've heard of Project Thor that the USAF ran, but never actually went through with. Then there's the Wiki entry on orbital bombardment and many references to Thor and fictional examples. (https://en.wikipedia.org/wiki/Kinetic_bombardment).

Why put artificial constraints on them? A reactionless drive just works (kinda magically, but hey, let's not digress). Apply power and it gives you some G-level of thrust until you run out of energy. Rather than trying to arbitrairly restrict the tech, why not focus on something that's easier and has less issues in the game - namely the hull materials that also magically protect ships from micro-meteorite damage. It would be far easier to simply state hull materials start to fail at certain speeds (higher speeds for materials like collapsed matter). And not just fail, but fail catastrophically and speeds above XX your ship has a percentage chance of encountering a solid object that damages or vaporizes the ship. So you retain science principles, you retain the magic of reactionless drives and the magic of hull materials - but you still get an upper limit that can be exceeded so long as they are willing to accept the risk of annhilation.

 

[phavoc]

They don't need to get anywhere near close to C to cause the ship into a devastating kinetic-kill weapon. Lightspeed is 300,000 km/s - a ship going at 1000 km/s is going to cause ridiculous damage (even an airburst if it breaks up in the atmosphere would wipe out a large area at those velocties at the very least).

Very true. Tuskunga wasn't going near C and it caused a helluva lot of damage. It was "only" a 10-30 megaton airburst. https://en.wikipedia.org/wiki/Tunguska_event

 

[Tenacious-Techhunter]

No. We're talking about a small nickel-iron asteroid, approx. 4-5m across, tossed and aimed from another star system at .99c

The object in question would weigh about 400 tons. So one puny thruster plate alone could accelerate it at .1g for 10 years, reaching .99c. This thruster plate would constantly draw 1MW and the energy source needs reactor fuel for 10 years. Attainable without much sweat in the Traveller universe.

If we round that up to 1000 metric tons, that’s equivalent to the dinosaur killer, at 132 Tera-Tons TNT equivalent, and 6x10^23 Jules; which makes the 400 metric Ton version 53 Tera-Tons TNT equivalent, and 2.4x10^23 Jules.

 

[Tenacious-Techhunter]

Tabletop RPG isn’t the same thing as works of fiction. Players and GMs have to depend on the information given to them, and have to form plans based on that information. That’s not something a member of a work of fiction’s audience has to do! Because the role of information is different between the two mediums, fiction authors can get away with a lot of crap that Tabletop RPG authors simply can’t. Information in a Tabletop RPG has to be actionable, because, at the spur of the moment, a player may come up with a clever plan, one that the GM was not expecting, and when the GM, desperate for some plausible constraints for that plan, turns to the book, all he currently gets is flowery language. If, instead, that technology was given some practical constraints to begin with, the GM and the player would at least have some common ground with which to put that plan into action. Instead, just like the Game Developer threw their hands into the air, the GM does.

When you play a fantasy rag do you need to know how the magic works?

If you want to cast a new spell, yes.

 

[Reynard]

Let's say approximately spherical. a 5m rock will have a displacement of 5 tons. Do they make engine, reactor, fuel, sensor, and computer systems that small to power and guide such a small object to near light velocity for ten years? Thruster plates are gravitic and there is no gravity in the outer system, between systems and until you reach the gravity wells of the next system. You rock will accelerate a short time in the initial system then coast at well below near light for eons. Probably run out of any power to plot system shifting and head off to deep space forever.

If it could work, what kind of grudge could someone have for 10 years in the future?

Cheaper and easier to build a spinal railgun on a jump ship or a rail launcher on a large asteroid to launch 5 ton payloads.

I think the big picture is, unless you're really rich and crazy, no empire is going to tolerate Weapons of Mass Extinction. Scorched Earth policy demands nasty retaliation.

 

[phavoc]

Let's say approximately spherical. a 5m rock will have a displacement of 5 tons. Do they make engine, reactor, fuel, sensor, and computer systems that small to power and guide such a small object to near light velocity for ten years? Thruster plates are gravitic and there is no gravity in the outer system, between systems and until you reach the gravity wells of the next system. You rock will accelerate a short time in the initial system then coast at well below near light for eons. Probably run out of any power to plot system shifting and head off to deep space forever.

If it could work, what kind of grudge could someone have for 10 years in the future?

Cheaper and easier to build a spinal railgun on a jump ship or a rail launcher on a large asteroid to launch 5 ton payloads.

I think the big picture is, unless you're really rich and crazy, no empire is going to tolerate Weapons of Mass Extinction. Scorched Earth policy demands nasty retaliation.

The magical drives in MGT don't need a gravity well to function (though as far as I am aware, the contragravity systems a starship uses to 'float' still require a gravity well).

If you want to do orbital bombardment of a planet, it's easy, and you don't need to launch from another system. Simply arrive in-system a few AU from your target, above/below the elliptical plane, accelerate towards where your planetary target is going to be when your kinetic energy projectiles arrive, then release them and jump out. There is no practical way to detect the objects that are coasting until it's too late. They will create a lot of destruction.

And of course star empires don't do this to each other. It's madness because there is no protection against it. The principles of MAD that have kept our planet from not having a nuclear war (or use of chemical/biological weapons) would remain. Granted you may have more unstable people with easier access to weapons of mass destruction, but one could reasonably argue that they simply don't get used. The use of chemical and bio-weapons here on Earth has been fairly restricted to extreme fringe groups and Tom Clancy novels. No reason why that would change in the future (cept Clancy may be spelled differently)

 

[alex_greene]

I think the big picture is, unless you're really rich and crazy, no empire is going to tolerate Weapons of Mass Extinction. Scorched Earth policy demands nasty retaliation.

I think this is covered in Secrets of The Ancients. The Spinward Marches is full of the wreckage caused by two thousand years of insanity. Warning enough for anyone save the most insane dictator going.

And it's up to the Referee to decide if the universe is going to spawn one of those, just so the Travellers can be pitted against him. Which would be the point of the story.

 

[phavoc]

I think the big picture is, unless you're really rich and crazy, no empire is going to tolerate Weapons of Mass Extinction. Scorched Earth policy demands nasty retaliation.

I think this is covered in Secrets of The Ancients. The Spinward Marches is full of the wreckage caused by two thousand years of insanity. Warning enough for anyone save the most insane dictator going.

And it's up to the Referee to decide if the universe is going to spawn one of those, just so the Travellers can be pitted against him. Which would be the point of the story.

That brings up a very good point any ref can make. Sure, people have tried in the past to deploy planet killers, but in every instance they have mysteriously failed and the group/government who deployed them mysteriously vanished. Who's to say that Grandfather has decided that he won't allow this to happen again? He's an uber ancient after all.

 

[Tenacious-Techhunter]

You can’t use badly written fiction to justify other parts of badly written fiction. Instead, you can write good fiction that doesn’t need justification. The solution to this problem is to constrain the performance of Reactionless Drives somehow so that they simply can’t perform at all well particularly close to C.

Who is using fiction? It's reality! The meteor impact crater that makes up much of the western portion of the Gulf of Mexico, the Tskunga meteor, to name just a few. I'm assuming you've heard of Project Thor that the USAF ran, but never actually went through with. Then there's the Wiki entry on orbital bombardment and many references to Thor and fictional examples. (https://en.wikipedia.org/wiki/Kinetic_bombardment).

You misunderstood me. My point was, you can’t use a fictional history of no relativistic kinetic kill devices being used to justify the nonviability of them in spite of their description. They’re just two pieces of badly written fiction that are inconsistent with one another, nothing more. One thing was never intentionally written in the context of the other. You either correct one piece, or you correct the other piece.

Why put artificial constraints on them? A reactionless drive just works (kinda magically, but hey, let's not digress). Apply power and it gives you some G-level of thrust until you run out of energy. Rather than trying to arbitrairly restrict the tech, why not focus on something that's easier and has less issues in the game - namely the hull materials that also magically protect ships from micro-meteorite damage. It would be far easier to simply state hull materials start to fail at certain speeds (higher speeds for materials like collapsed matter). And not just fail, but fail catastrophically and speeds above XX your ship has a percentage chance of encountering a solid object that damages or vaporizes the ship. So you retain science principles, you retain the magic of reactionless drives and the magic of hull materials - but you still get an upper limit that can be exceeded so long as they are willing to accept the risk of annhilation.

You put meaningful constraints on them so they can be used. Once you assign meaningful limits to these things, the GM doesn’t have to worry about the players randomly generating doomsday devices, and can instead leave them to come up with legitimately clever solutions to problems, as opposed to just game-breaking Munchkinry.

 

[Tenacious-Techhunter]

I think the big picture is, unless you're really rich and crazy, no empire is going to tolerate Weapons of Mass Extinction. Scorched Earth policy demands nasty retaliation.

I think this is covered in Secrets of The Ancients. The Spinward Marches is full of the wreckage caused by two thousand years of insanity. Warning enough for anyone save the most insane dictator going.

And it's up to the Referee to decide if the universe is going to spawn one of those, just so the Travellers can be pitted against him. Which would be the point of the story.

That brings up a very good point any ref can make. Sure, people have tried in the past to deploy planet killers, but in every instance they have mysteriously failed and the group/government who deployed them mysteriously vanished. Who's to say that Grandfather has decided that he won't allow this to happen again? He's an uber ancient after all.

That’s a bit too Deus Ex Machina for something so common and broadly reaching. I mean, it’s practically Santa Claus; it strains belief that one Ancient can control all the relativistic speed devices within range of an entire Galaxy.

Might be a fun one-shot, though.

 

[phavoc]

You put meaningful constraints on them so they can be used. Once you assign meaningful limits to these things, the GM doesn’t have to worry about the players randomly generating doomsday devices, and can instead leave them to come up with legitimately clever solutions to problems, as opposed to just game-breaking Munchkinry.

Me doth think this is a solution looking for a problem. I've yet to be in a game where the deployment of planetbusters was an issue. You forget that we have this doomsday problem today with our pokey little ol reaction drives. Hell, we have the Orion drive too as a doomsday weapon. We don't need no stinkin reactionless magical drives to do any of this.

 

[phavoc]

That’s a bit too Deus Ex Machina for something so common and broadly reaching. I mean, it’s practically Santa Claus; it strains belief that one Ancient can control all the relativistic speed devices within range of an entire Galaxy.

Might be a fun one-shot, though.

Nah, it would be well within the parameters of Grandfather to do this. And he wouldn't even need omniscience to do so. He could build some robots that would take care of all this for him through automation. For a being that can create a pocket universe, seeding the galaxy (cause we have no idea if the Ancients ever left it) or even just the Traveller-inhabited portion would be child's play.

Ancient tech isn't limited by what the Imperium does. Disintegrators, system-to-system teleportation, etc. It would be EASY to do it.

 

[Tenacious-Techhunter]

Let's say approximately spherical. a 5m rock will have a displacement of 5 tons. Do they make engine, reactor, fuel, sensor, and computer systems that small to power and guide such a small object to near light velocity for ten years? Thruster plates are gravitic and there is no gravity in the outer system, between systems and until you reach the gravity wells of the next system. You rock will accelerate a short time in the initial system then coast at well below near light for eons. Probably run out of any power to plot system shifting and head off to deep space forever.

If it could work, what kind of grudge could someone have for 10 years in the future?

Cheaper and easier to build a spinal railgun on a jump ship or a rail launcher on a large asteroid to launch 5 ton payloads.

I think the big picture is, unless you're really rich and crazy, no empire is going to tolerate Weapons of Mass Extinction. Scorched Earth policy demands nasty retaliation.

The problem is, Relativistic Kinetic Kill devices like this aren’t limited to governments... they’re freely available for “little Timmy’s science fair project”.

Sending a 1 gram solar powered toy rocket between two star systems “for fun” would cause it to arrive at about 99.99% the speed of light, and if it should hit something, it destroys with with the blast of 1.5 Mega Tons of TNT, at 6.3x10^15 Jules.

Can a government be held responsible for some dumb 4 year old who hooked up a solar panel to a toy rocket? Can the poor kid? Can the parents? Universes like this just shouldn’t exist. The game rules should prohibit it.

 

[alex_greene]

I think this is covered in Secrets of The Ancients. The Spinward Marches is full of the wreckage caused by two thousand years of insanity. Warning enough for anyone save the most insane dictator going.

And it's up to the Referee to decide if the universe is going to spawn one of those, just so the Travellers can be pitted against him. Which would be the point of the story.

That brings up a very good point any ref can make. Sure, people have tried in the past to deploy planet killers, but in every instance they have mysteriously failed and the group/government who deployed them mysteriously vanished. Who's to say that Grandfather has decided that he won't allow this to happen again? He's an uber ancient after all.

That’s a bit too Deus Ex Machina for something so common and broadly reaching. I mean, it’s practically Santa Claus; it strains belief that one Ancient can control all the relativistic speed devices within range of an entire Galaxy.

Naval architects might be told by their governments to install governors in every M-Drive to prevent ships from being used in this way, by aiming the prow of the ship at a planet and going at ramming speed at it.

As a scenario, using ships' drives as doomsday weapons is implausible. Just have them transport xenomorphs or nanocloud containers and deliberately sabotage the containers to rupture and release their WMD contents on arrival. There are many ways to inflict mass casualties on some planet. You don't need to put a breeze block on the pedal and keep it there for a year.