How do you build Drives?

[Jagged]

Re: How do you build Drives?

 

I think that highlights the most important part of FTL a referee needs to consider and thats the speed of communication compared to the speed of travel.

 

One of the main effects of your choice are the outcomes for law inforcement and trade. If communication is noT faster than travel then it becomes much easier to be a criminal in one place and law abiding citizen in another. It also makes it harder for central government and creates a more fudal environment.

 

Sometimes as a referee/story teller you want communications to be both fast and slow. You can justify such a situation if you assume that interstella communication requires the establishment of some kind of tunnel or warp just like travelling does, but once established it can be held open to allow instantaneous chatter.

 

This allows your star ship to be out of communication for large amounts of time but can arrange face to face discussions with important ambassadors when the plot demands

[Nyrath]

Re: How do you build Drives?

 

In the "Renegade Legion" series of wargames, there was FTL communication that was faster than a starship. But the communicator was a titanic orbital installation.

 

So they were prime targets during times of warfare. Take out a few key comm units and you can cut off large sectors of the Empire from direct communication with Imperial Terra. So they were often the centers were interstellar battles occured.

[Yansuf]

Re: How do you build Drives?

 

I think that highlights the most important part of FTL a referee needs to consider and thats the speed of communication compared to the speed of travel.

 

One of the main effects of your choice are the outcomes for law inforcement and trade. If communication is now faster than travel then it becomes much easier to be a criminal in one place and law abiding citizen in another. It also makes it harder for central government and creates a more fudal environment.

 

Do you mean: "If communication is NOT faster than travel"?

Because it doesn't make sense to me the other way.

[Kristopher]

Re: How do you build Drives?

 

Do you mean: "If communication is NOT faster than travel"?

Because it doesn't make sense to me the other way.

 

That's what I was thinking -- if communication is limited to the speed of travel, as opposed to being much faster, that encourages the formation of local governance.

[megaplayboy]

Re: How do you build Drives?

 

Trek and Wars have comm faster than travel, but it's not instantaneous over long distances in Trek, IIRC. Wars looks kinda like it might be, though.

 

I just tend to write up flight with some megascaling, plus a basic FTL rating. "Jump" drives (or MS teleport travel) tend to be the exception rather than the rule.

Ramping up to warp speed in my campaigns tends to require:

1.) accelerating out of local gravity wells (i.e., FTL near planets generally isn't possible or advisable)

2.) some initial plotting of nav points

3) acceleration to a relatively high sublight speed

 

So the speed of combat will depend on where in that process hostile ships encounter each other.

[DusterBoy]

Re: How do you build Drives?

 

In my as-yet unwritten up Federation of United Systems campaign, starship captains are autonomous since FTL "radio" is not fast enough to permit real-time comunications.

 

It's like in the Star Trek:TOS episode "Balance of Terror" where the Enterprise is on the border of the Neutral Zone and radios for permission to cross. In the meantime the Enterprise comes under attack from a Romulan warbird and is forced to defend herself - which means crossing over into the NZ. At the end, when many hours of story-time have passed, Uhura finally picks up a message from Starflet Command authorizing the Enterprise into the NZ. The messages had taken all that time to make that round trip.

 

(If I've made any mistakes summarizing the episode I apologise. I've only seen it once a long time ago.)

[Kristopher]

Re: How do you build Drives?

 

Trek and Wars have comm faster than travel' date=' but it's not instantaneous over long distances in Trek, IIRC. Wars looks kinda like it might be, though.[/quote']

 

In Trek, comms is at the speed of plot, even more so than travel.

 

One episode will have real-time comms between the ship and some far-off admiral or starbase, and then another will have the captain watching a message from somewhere and then sending a reply message off, waiting some time for the next reply.

[phookz]

Re: How do you build Drives?

 

I was watching an old western the other day and it got me to thinking on communications. In the old west, you had near instantaneous communication via telegraph, but even then you didn't really have a conversation; you figured out what you wanted to say and sent it, then waited for a response (or not, based on the message). On top of that, you couldn't just pick up the phone; you had to go to the railroad (usually) and get the telegraph operator to send the message for you.

 

This really helped with the frontier nature of the old west, I think, and would definitely change the tone of the Star Hero campaign that had similar limitations (ala the Orbital platforms previously mentioned).

 

It's easy to take for granted the near instantaneous and mass communication and data transfer we have at our fingertips. With instant global news coverage, it's often hard to imagine what the world was like before this. I think it's an important consideration for a campaign setting.

[Jagged]

Re: How do you build Drives?

 

Do you mean: "If communication is NOT faster than travel"?

 

Don't know what you mean?

 

<.<

 

>.>

 

*cough*

[Kraven Kor]

Re: How do you build Drives?

 

 

In game terms, I think that a Vorkosigan Saga jumpship would be built with Teleportation, with the appropriate levels of MegaScale, OAF Bulky (the Necklin Rods) and the appropriate levels of Increased Mass so the ship itself can make the jump. (Only one ship at a time can get through a wormhole).

 

To the passengers, the trip seems instantaneous. So far, the navigator's POV has not been described.

 

She kind of described it - I forget which book, but the guy who Miles saved on Beta who was a deserter... all I remember is him saying how it might seem instantaneous to the passengers, but to the pilot time stretched out and their perceptions changed to that of the necklin rod's being affected by the wormhole or some such. It was not described in detail, but at least touched on.

 

My drives:

 

(Collection of links regarding my musings and the help I've received is here.)

 

My setting has several types of Sub-Light and FTL drive systems, most working on the same principles.

 

I wanted space travel to be slow, but not "why bother?" slow.

 

Most species use fairly traditional torch drives for moving around within a solar system - I built it as Flight with a "Real Acceleration" Modifier to signify that the inches of flight can be added each phase. Most ships are capable of faster speeds, but 5" flight using this "Real Acceleration" model = 1 Gee of acceleration. Human ships mostly use high-efficiency (non-newtonian, rubber, broken, shame on me for thinking about it) Ion or Plasma drives. Most aliens are similar save for the Akashi (insanely advanced jellyfish aliens), who use Gravitic propulsion for both Sublight and FTL. For safety reasons, human ships never get much faster than about .1 C, in Sublight or while traversing FTL "tunnels." Some more advanced species, who can more properly comprehend the relativistic effects, go faster.

 

FTL travel is done either by wormhole, or by the "Tunnel" drives (as humans call them - most aliens use similar technology.) Wormholes and "Tunnel" drives operate on similar science. Wormholes exist between binary / trinary systems and their closest neighboring stars, essentially eddies in the spatial topography created by massive, conflicting, and moving gravity wells. Basically, there is a shortcut between binary systems and their neighbors if you know how to find and navigate them. This requires a special drive system, the Gravitic Drive, and a lot of computer power. The "Tunnel" drives operate on the same concept, but use massively powerful generators to create a focused Gravitational affect ahead of the vessel, creating your own miniature wormholes. Either way, you are basically creating and/or navigating a tunnel of space-time that is shorter than the actual distance. Humans move between systems in days to weeks. Most aliens are a little faster but not by much.

 

The real trick to this FTL is that you cannot create this focused tunnel in any kind of close proximity to any other significant gravity well (it is a uni-directional gravitational field, not a typical mass-created well.) Older drives have to be farther away than newer ones, but not even the Akashi can FTL to closer than about a few light-minutes from an Earth-sized planet, where they then have to use traditional propulsion to travel within a solar system.

 

The FTL is basically built as megascale telportation, must cross intervening space - while in the "tunnel" they are still in "real space" just a part of it they create themselves. A ship could be followed into their tunnel, seen as they traverse the tunnel (if looking from the right angle and you don't mind the info being years out of date), etc.

 

Human ships with the Tunnel Drive are incredibly rare and expensive, typically either superfreighters operated by the UTC or the various Nationals, or Military Carriers, Recon Ships, or Rapid Response Cruisers. There is no such thing as a privately owned and operated Starship in my setting - all craft are either owned by the UTC, one of the Nations established in space, or one of a few megacorps licensed to operate ships. All ships have kill codes which send their AM Reactors into overload and disintegrate the ship so as to prevent the instant kinetic kill weapon problem.)

 

Aliens have more-or-less similar set-ups, the more advanced having cheaper and faster and more FTL ships. The only thing that really keeps us from being overrun by aliens is that most of the older civilizations have figured out that interstellar war is difficult and expensive to wage, with little real benefit to justify it.

 

My FTL concept is loosely based on the wacky theories of one Bob Lazar

[Kraven Kor]

Re: How do you build Drives?

 

Also, my setting has no FTL Comms - beyond sending a message on an FTL ship that will take days or weeks to arrive, and days or weeks more to get a response.

 

I tried to generate some conversation about the implications of that, but it degenerated into a discussion of how my FTL drives were completely implausible

[SvZurich]

Re: How do you build Drives?

 

Partial to David Weber's system in his Honor Harrington series.

 

In a solar system, impellar bands (focused gravity planes above and below the ships) are sublight with a need to turnover the ships 180 degrees for deceleration. Fantastic sublight speeds take time to reach and negate.

 

Outside a solar system (defined as a distance from a significant gravity well), you have your hyperspace drive punch through various bands of hyperspace to compress travel distance. The "higher" a band you can reach and sustain, the faster you travel. At least until you want to stop or hit a gravity wave.

 

At a gravity wave (a current of intense gravity affecting hyperspace), impellar bands will destroy the ships when reacting to them. You reconfigure the bands into Warshawski sails to draw power from the waves and impart motion. You effectively sail in a river at much higher speeds than you could reach via hyperspace alone.

 

Lastly, there are wormholes. This is where gravity waves somehow connect two points in space, allowing for instant transit via Warshawski sail. The more mass you transit in a short time, the longer the wormhole is destabilized. Jump a fleet through the hole at once, and you lock down reinforcements for 18+ hours.

 

For the most part, there are no FTL communications (later books allowed FTL via gravitic pulses from satellite relays in a "morse code" manner in a solar system), so you send a courier ship to its destination to relay news. Intercept the courier, and you can lock out news.

[Jhamin]

Re: How do you build Drives?

 

A while back I built a short lived Star Hero game around the old Master of Orion II PC game. I decided to model the drives to work as they did in the game & then use some technobabble to explain why during play.

 

The basic mechanic in the PC game was that there was a hierarchy of Engine types, but that they all performed in the same way, the only difference was that better engines got you there faster.

 

The functions of the engines were:

1) Combat Maneuvering. You could travel inside a Solar System. Combat usually started with you some distance from a planet & it took a few Minutes/combat turns to reach Orbit.

2) General Maneuvering. In general, once you were in a star system you could generally reach any planet or Asteroid belt very quickly. It wasn't odd for one ship to defend 3-5 planets in the same Star System during the same month.

3) On the Galaxy map distance between star systems was measured in "Parsecs". If you sent a ship to another system it began travel & was out of communication until it arrived. It's speed was a function of how many parsecs it could travel per turn/month.

 

A few of the interesting quirks of the game included:

- FTL Ships could only travel to StarSystems. No fleets assembling in the void & then going somewhere. I chose to represent this in hero system by saying that you could only Enter or Exit Hyperspace if you were both in a Vacuum AND inside the Gravity Well of a Star

- Once a ship launched to another star system you could detect them across interstellar distances, how far was related to sensor tech. You often knew several turns/months ahead of time if a ship was coming to one of your planets.

- Fuel cell Tech was separate from engines. It was theoretically possible to have engines that could carry you farther in a Month/Turn than your fuel cells allowed you to go in your entire trip! (This was rare in practice)

- Once ships were in Hyperspace it was no longer possible to redirect them. They were out of communication and would arrive at their destination barring accidents.

- You could Jump to Hyperspace to avoid a fight, but only if the enemy hadn't researched (and installed) Warp Dissipation tech which would prevent access to Hyperspace for enemy ships until disabled. Fleets breaking off an engagement they could not win was common.

- The jump to Hyperspace in combat happened one full (pc game) turn after you initiated it. Shields and Weapons still worked during the turn you jumped, but it was not possible to move while waiting. It was very common to lose ships to enemy fire after they had begun to Jump.

 

 

The end result of all this was that Planets became the main battleground during the game, with occasional skirmishes between planets if everyone agreed to fight there rather than leave. You knew what star system enemies were heading for and could sometimes gather a fleet in time to defend it. No matter which planet they attacked when they got there your fleet could intercept. As defender, an investment in Planetary Defenses could often repel 1-3 battleships of equal technology to your own. A heavy investment might make some planets harder to damage than entire fleets. If as the attacker you wanted to bug out you likely could, but would then be stuck spending a bunch more turns/months heading back to a friendly system.

 

From a gaming point of view, players had a lot of freedom in a single star system, and could travel to others, but the choice to do so was a major one. If events were transpiring somewhere else it would take literally months for them to get there once they jumped.

 

This is the engine I built for the Millennium Falcon sized Exploration ship the PCs had. It represents an early engine tech, very early along the tech tree. More advance engines would have larger Multipower reserves & could propel their ships faster but would still retain the same slots & modifiers in each slot. The point cost and capability (In Hero terms) for the engines would remain the same for larger or smaller ships.

 

Fusion Engines: Multipower, 80-point reserve, all slots Full Phase to Change Slots (-1/4) 64 real points

1) Fusion Thrusters (Combat Maneuver): Flight 40"; Costs Endurance (-1/2), Full Phase to Change Slots (-1/4) Real Cost: 5

2) Fusion Drive (Interplanetary Speeds): Flight 11", Megascale (1" = 1 Million KM; +4), Can Be Scaled Down: 1" = 1 1,000 KM; Costs Endurance (-1/2), Full Phase to Change Slots (-1/4) Real Cost: 5

3) Fusion Charged Hyperdrive (FTL Hyperspace Travel): Teleportation 5", Megascale (1" = 100 lightyears; +4), Can Be Scaled Down: 1" = 1 Light Day (+1/4); Extra Time (1 Week per Parsec, -4 1/2), Visible (-1/4) Increased Endurance Cost (7x END; -3), Costs Endurance (-1/2), Only in vacuum while in a Stable Stellar Gravity Well (-1/2), Full Phase to Change Slots (-1/4) Real Cost: 2

 

And separate from the multipower, but still considered part of the Engine:

Engine Overload: Killing Attack - Ranged 10d6, Trigger - Security Command Code (+1/4), Explosion (+1/2); 1 Charge which Never Recovers (-4), Extra Time (1 Turn (Post-Segment 12), -1 1/4), No Range (-1/2), Real Weapon (-1/4) Real Cost: 37

 

 

They also had an End Reserve to represent their Deuterium Fuel Cells. This END reserve scaled with the ships so the bigger boys could power their big guns.

[HawksmoorSD]

Re: How do you build Drives?

 

I'm planning on a game around the turn of the year that will have some form of FTL. My idea is that the entire ship will be held in some sort of magnetic ring and literally fired at its destination, much like a space rail gun. I'm thinking of using some sort of cold sleep so people don't age. The catch is that once you get to somewhere new you'll need to build a new mag ring to be able to send you back.

 

I just have no idea or reason to stat it out. The first shot, the players, are going to be Lost In Space as it were.

[prestidigitator]

Re: How do you build Drives?

 

I usually base all interstellar travel on the FTL Travel power. Wormholes have different SFX from "warp drives" and hyperspace is a different SFX still. Those with the same SFX can usually interact with each other if travel times are significant, but not always (e.g. two ships travelling in "otherspace" might be able to interact, but two ships travelling along different wormholes between the same two destinations might not be able to).

 

When appropriate, the power might take Limitations to restrict the amount of distance that can be travelled at once (and possibly Limitations to make activation costly as well). For example, a "teleportation" based drive might be built to be able to travel 10 lightyears per Phase, then restricted to a maximum of a single Phase worth of travel time per activation/use.

 

I usually also give all interstellar drives Limitations (or repercussions) on how close they can come to gravitational bodies, from simple impossibility to navigational risks, to side effects like ship damage or drive burnout. Always nice to give reasons for slower velocities that make "normal" space combat feel more justified.

[megaplayboy]

Re: How do you build Drives?

 

The trickiest part about space combat is the weapon velocities, in most campaign settings, are limited to light speed or slower. So your combat speed is going to be slower than light, usually much slower.

In orbit, 1m=1km is probably a solid scale to work with. For transorbital, near-planetary fights, maybe 1m=10km. For in-system fights that aren't near planets, maybe 1m=100km, for near-system battles maybe you can scale up to 1m=1000km. And, for deep space battles with no gravity wells and lots of prep time to get up to speed, maybe 1m=10k km.

 

at 1m=10k km(or 1 hex = 10k km), 1 light second is just 30 hexes across. IIRC, this is typical SFB scale.

 

The only scale I'm familiar with that was much longer was the old Space Opera scale, which did involve FTL combat--beam weapons could hit targets as far as 1300 light seconds away, and torpedo/missile weapons as far as 1 light hour!

[Silverhawk]

Re: How do you build Drives?

 

I'm also partial to Weber's system. I've been working on a 5th edition version to use for a campaign that I am slowly developing.

 

Partial to David Weber's system in his Honor Harrington series.

 

In a solar system, impellar bands (focused gravity planes above and below the ships) are sublight with a need to turnover the ships 180 degrees for deceleration. Fantastic sublight speeds take time to reach and negate.

 

Outside a solar system (defined as a distance from a significant gravity well), you have your hyperspace drive punch through various bands of hyperspace to compress travel distance. The "higher" a band you can reach and sustain, the faster you travel. At least until you want to stop or hit a gravity wave.

 

At a gravity wave (a current of intense gravity affecting hyperspace), impellar bands will destroy the ships when reacting to them. You reconfigure the bands into Warshawski sails to draw power from the waves and impart motion. You effectively sail in a river at much higher speeds than you could reach via hyperspace alone.

 

Lastly, there are wormholes. This is where gravity waves somehow connect two points in space, allowing for instant transit via Warshawski sail. The more mass you transit in a short time, the longer the wormhole is destabilized. Jump a fleet through the hole at once, and you lock down reinforcements for 18+ hours.

 

For the most part, there are no FTL communications (later books allowed FTL via gravitic pulses from satellite relays in a "morse code" manner in a solar system), so you send a courier ship to its destination to relay news. Intercept the courier, and you can lock out news.

[SvZurich]

Re: How do you build Drives?

 

Two more quirks to the Honorverse system regarding impellor bands..

 

1) They are impenatrable. Incoming missiles and energy/mass shots can be completely negated by turning the ship to allow it to hit the band. Rotate the ship to dodge. Missiles are trained to attempt to slide/shoot in between bands. To counter, weaker "sidewalls" are generated to distort attacks, and to open "ports" to shoot through. Sidewalls cannot be created at the ends of the ships, so the bow and stern are open to attacks if a maneuver fails.

 

2) Wedges are nigh infinite masses of contained and focused gravity, do not let your wedge touch another. Ever. The only exception is weak missile wedges hitting a ship's wedge. Fleet formations have to keep their spacings tight but allow enough room for the ships to spin on any axis without touching another ship's wedge. If two wedges meet, they short each other and destroy the ships.

 

And lord help you if your inertial dampeners/sump goes out. Once the ship stops and is recovered, there will be liquid messes smeared throughout the ship in place of the crew.

 

And if your Warshawski sail is destroyed in a gravity wave, pray for a rescue before you reach the end of the line. For this reason, ship combat in gravity waves is very rare (and happens in the books).

[Nyrath]

Re: How do you build Drives?

 

Two more quirks to the Honorverse system regarding impellor bands..

All of which are carefully crafted to make interstellar combat act like a three dimensional version of Wooden Ships and Iron Men. Sail powered vessels unloading broadsides at each other.

[SvZurich]

Re: How do you build Drives?

 

Yep! Those details make me love it more and more.

[Yansuf]

Re: How do you build Drives?

 

I love the Honerverse, but the basic impeller wedge drive does violate conservation of energy.

[Zeropoint]

Re: How do you build Drives?

 

Well, of course. ANY reactionless thruster violates conservation of energy.

[Yansuf]

Re: How do you build Drives?

 

Well' date=' of course. ANY reactionless thruster violates conservation of energy.[/quote']

 

Not always.

They violate conservation of momentum, but can be made so that they obey conservation of energy.

These don't obey either.

[Kraven Kor]

Re: How do you build Drives?

 

Not always.

They violate conservation of momentum, but can be made so that they obey conservation of energy.

These don't obey either.

 

Question:

 

I linked that Bob Lazaar "Gravity Generator" stuff that I'm loosely basing my FTL on and am curious.

 

Let's say this drive system is plausible; does it break either or both of those laws? General idea is a nuclear reaction that turns the energy into a gravity wave and either pushes or pulls against other gravity fields. So the 'thrust' is provided by gravity, not the exhaust of reaction mass. Is that a reactionless drive? Or no, because there is a nuclear reaction that requires fuel, albeit a tiny amount?

[Nyrath]

Re: How do you build Drives?

 

I linked that Bob Lazaar "Gravity Generator" stuff that I'm loosely basing my FTL on and am curious.

 

Let's say this drive system is plausible; does it break either or both of those laws? General idea is a nuclear reaction that turns the energy into a gravity wave and either pushes or pulls against other gravity fields. So the 'thrust' is provided by gravity, not the exhaust of reaction mass. Is that a reactionless drive? Or no, because there is a nuclear reaction that requires fuel, albeit a tiny amount?

 

Short answer: yes, Bob Lazar's flying saucer propulsion system is a reactionless dirve.

 

Long answer: Fuel is not reaction mass

 

In a rocket, there is a difference between "fuel" and "reaction mass." Rockets use Newton's third law of Action and Reaction in order to move. Mass is violently thrown away in the form of the rocket's exhaust and the reaction accelerates the rocket forward. This mass is of course the "reaction mass."

 

The "fuel" is what is burned or whatever to generated the energy to expel the reaction mass. For example, in a classic atomic rocket, the fuel is the uranium-235 rods in the nuclear reactor, the reaction mass is the hydrogen gas heated in the reactor and expelled from the exhaust nozzle.

 

So it does not matter that Bob Lazar's flying saucer engines use nuclear fuel. Since they do not use reaction mass to provide propulsion, they are a reactionless drive