Star Drives

[Tom Kalbfus]

What kind of Star Drives can you think of and what would be their campaign effect?

1. There is the Standard Traveller Jump Drive, you know about that, but what other kinds of Sar Drives could their be and what would be their effect if you used them in your campaign.

2. Is the Wormhole Drive, the structure of the wormhole drive is an expandable ring. Typically the Wormhole drive is located in front of the starship in the form of a small ring. When activated the Wormhole drive creates a wormhole in the center of its ring, the other end opens up somewhere else in the Universe. the wormhole starts out microscopic and is slowly expanded as the ring that creates it also expands to be eventually larger than the diameter of the starship, the starship then moves itself through its own wormhole ring, and when completely through the wormhole ring ends up back at its small state but aft of the starship, then a track along the starship's side moves the little ring back to the front so it can be activated again.

3. The Stutterwarp Drive, this drive creates a temporary warp bubble around the starship which pushes the starship at superluminal speed a relatively short distance ahead in space. Since there is a communicaton problem between the ship and the positive and negative mass singularities in front of and behind the starship, the warp envelope is created such they its own dynamic result in its destruction releasing the starship back into normal space some distance ahead from its original position. A typical warp bubble lasts a nanosecond, expands faster than the speed of light, enclosing the starship from ahead and then collapsing behind it back into nothing from which it came. A stutterwarp unleashes a warp bubble at least one million times per second, each warp bubble displaces the starship 300 meters ahead of its original position, this simulates travel at the speed of light, this effect is initiated at the 100 diameter limit from Earth, as the stutter warp drive moves further away from this mass each warp bubble has greater displacement. A 3 km displacement is 10 times the speed of light, a 30 km displacement is 100 times the speed of light in effect.

 

[Infojunky]

Drives aren't so much the question, rather speed of communication is.

If the speed of communication is still the speed of the fastest ship then very little changes in a Traveller-esqe universe.

 

[Condottiere]

What do they call 'em, McGuffins?

We don't really know how they work, since they are fictional devices working on fictional physics. You'll have to find a method of transportation you're comfortable with, but the Jump Drive is so canonically central to the Traveller milieu, much like hyperdrive in Star Wars and warp drive in Star Trek.

 

[locarno24]

The two alternates in the rulebook are the Warp Drive and the Hyperspace Drive.

The warp drive has well-defined rules but would also massively shift the universe if it is a standard 'thing':

A Warp Drive gives you a consistent speed in real space. This doesn't make long journeys massively faster but it does make them more fuel-efficient; the warp drive requires double reactor fuel but that's negligible compared to the fuel a jump engine eats.

Where a Warp engine really shines in campaign is that it has no 'minimum jump' - a Warp-6 ship can get to another star a parsec away in just a little over a day, and to anywhere within a star system in a few seconds. This makes exploiting a star's resources massively easier, and you can colonise and supply off-world facilities easily - hell, you can realistically commute to them.

This also changes the 'local governance' dynamic; the feudal nature of imperial nobility, etc, etc, is due to the fact that it takes a fortnight to get any instruction from out-system. By comparison, in a small clustered polity - say two or three adjacent stars - you can send someone, they'll be there tomorrow, have a day discussing the issues, come back, and do that again if you don't like the first answer, and still take less than half the time for a jump drive based ship.

Lastly, I think we worked out that between having to buy less fuel, being able to carry more cargo per trip (because you require less space for fuel) and being able to make 2-3 times as many trips in the same time period, the price for shipping goods between star systems was about 10% of what it is in a campaign universe with jump engines. Which makes corporate penetration and multistellar industry more attractive, which, in turn, leaves less space for the tramp traders....

 

[Lord High Munchkin]

There is also the drive model from the Traveller version of Babylon 5.

However, as has been said, communications is the real issue.

 

[Tom Kalbfus]

The two alternates in the rulebook are the Warp Drive and the Hyperspace Drive.

The warp drive has well-defined rules but would also massively shift the universe if it is a standard 'thing':

A Warp Drive gives you a consistent speed in real space. This doesn't make long journeys massively faster but it does make them more fuel-efficient; the warp drive requires double reactor fuel but that's negligible compared to the fuel a jump engine eats.

Where a Warp engine really shines in campaign is that it has no 'minimum jump' - a Warp-6 ship can get to another star a parsec away in just a little over a day, and to anywhere within a star system in a few seconds. This makes exploiting a star's resources massively easier, and you can colonise and supply off-world facilities easily - hell, you can realistically commute to them.

This also changes the 'local governance' dynamic; the feudal nature of imperial nobility, etc, etc, is due to the fact that it takes a fortnight to get any instruction from out-system. By comparison, in a small clustered polity - say two or three adjacent stars - you can send someone, they'll be there tomorrow, have a day discussing the issues, come back, and do that again if you don't like the first answer, and still take less than half the time for a jump drive based ship.

Lastly, I think we worked out that between having to buy less fuel, being able to carry more cargo per trip (because you require less space for fuel) and being able to make 2-3 times as many trips in the same time period, the price for shipping goods between star systems was about 10% of what it is in a campaign universe with jump engines. Which makes corporate penetration and multistellar industry more attractive, which, in turn, leaves less space for the tramp traders....

For the Traveller Jump Drive, the transit time is proportional to the number of jumps you make, not the distance jumped.

One interesting alternative is the Star Frontiers "Jump Drive". The requirement for the Star Frontiers "Jump Drive" is that the starship reaches 1% of the speed of light. This is a bit of a problem since this requires that we ignore that all motion is relative as is called for by Einsteinian laws. No matter how fast you go below the speed of light, the speed of light measured by any observer is always the same, so there is nothing really special about 1% of the speed of light, the only speed that is special is the speed of light, and that is unreachable by accelerating a starship constantly. But the 1% speed of light requirement can be stated as a distance instead.
Take as a rule, how far would you get if you accelerated constantly at 10 meters per second squared in one direction until you reached the 1% of the speed of light relative to your starting point.

1% of the speed of light is 3,000,000 meters per second approximately. It takes 300,000 seconds to reach that speed when accelerating at 10 meters per second squared., the distance travelled under this acceleration and over this time is 3 au or 450,000,000 km

So lets say we altered the Traveller Jump Drive in the following way:
1. We make the Jump Drive instantaneous
2. We increase the Jump Limit to the cube root of the mass in Solar Masses times 4 AU or 600,000,000 km from the star, since we're already starting at 1 AU from the Sun in the case of the Earth, as its the Star we're trying to move away from, not the planet so much. It takes 3.472222222 days to reach this distance at 1 g, so to accelerate to a sufficient distance to make this jump takes approximately 3.5 days and to decelerate after the jump is made takes another 3.5 days for a total travel time of 7 days, this is much the same amount of time as to make a standard Traveller Jump, except that time is spend in normal Space not Jump space. (And since the jump is instantaneous, there is no need for Jump Space) Now 450,000,000 can be covered more quickly with higher accelerations, so what if we just got rid of artificial gravity the way Star Frontiers did? That means if you accelerate your ship at 2-g you feel the full 2 gravities of acceleration, unfortunately that would force us to throw away all the standard floor plans of the Traveller starships we have, but lets say we limited the maximum speed of starships to 1% of the speed of light due to fuel requirements? That means if you accelerated twice as fast you'd use your fuel up twice as quickly, you still reach 1% of the speed of light and have to reserve the remaining fuel to slow down again.

These would be the travel times with the various maneuver drives
Maneuver-1 = 7 days
Maneuver 2 = 5.2 days
Manuever 3 = 4.6 days
Maneuver 4 = 4.3 days
Manuever 5 = 4.2 days
Maneuver 6 = 4.1 days
That is for a star of 1 solar mass
Less massive stars would have shorter travel times. Thing is more massive stars get brighter at a faster rate than they increase in mass, fortunately stars more massive than Sol aren't very common, and less massive stars are more common, so the habitable zone will be closer. so there would be further to travel to get to the jump limit.

 

[Tom Kalbfus]

Star Mass --------> Jump Limit
O > 16 --------> 10.0793684 AU
B = 15 ------------> 9.864848297 AU
B = 12 ------------> 9.15771394 AU
B = 8 --------------> 8 AU
B = 4 --------------> 6.349604208 AU
A = 2.1 ------------> 5.12231666 AU
A = 1.4 -----------> 4.474755768 AU
F = 1.2 ------------> 4.250634277 AU
G = 1 --------------> 4 AU
K = 0.8 ------------> 3.713271067 AU
M = 0.45 ---------->

 

[Reynard]

The other drive mentioned in the core book is the Transport type, the instantaneous jump usually described as folding two points in space so they touch. The magic word 'wormhole' is often evoked. We see it in the movie Dune and the Dragonstar RPG uses a mass produced magic relic in their ships. Instant communications and the art of interstellar war is completely different as fleets appear at a planet's 100d limit. Starships need only spacecraft amenities and no low berths for passengers and crew.

I'm impressed we never hear anyone using this alternate in their campaigns.

 

[locarno24]

For the Traveller Jump Drive, the transit time is proportional to the number of jumps you make, not the distance jumped.

That's a jump drive. The alternate warp drive rules in the core book instead gives you a speed of [Drive Rating] Parsecs per week, at a cost of double power plant fuel consumption.

And yes, the main drivers are whether or not FTL communications is allowed - if anything, that changes politics in a universe far more than the drive 'physics'.

 

[Condottiere]

One interesting narrative from the Honorverse is that you have two methods of FTL travel.

 

[Tom Kalbfus]

For the Traveller Jump Drive, the transit time is proportional to the number of jumps you make, not the distance jumped.

That's a jump drive. The alternate warp drive rules in the core book instead gives you a speed of [Drive Rating] Parsecs per week, at a cost of double power plant fuel consumption.

And yes, the main drivers are whether or not FTL communications is allowed - if anything, that changes politics in a universe far more than the drive 'physics'.

There are two types of FTL communication, one is a sort of radiation that propagates at FTL velocity, the other is a side effect of FTL travel, that is a starship carries a message and then broadcasts it via the electromagnetic spectrum once it arrives at the target system. For instance the Star Frontiers Jump Drive would allow for some not quite instantaneous communication. You would have a communications satellite located at the jump limit in orbit around a star, it comes equipped with a Jump Drive, the Satellite receives a number or messages until its scheduled departure time and then it jumps to another system while at the same time another Communications satellite arrives from another system to replace it, it then broadcasts all the messages it collected toward the target planet and begins receiving more messages from that planet until its scheduled departure time. If the satellites jump every 30 minutes communications between systems take at most that long.

 

[Wil Mireu]

Pick up GURPS Space, that'll give you lots of ideas for alternative drives and their effect on settings.

 

[Tom Kalbfus]

Pick up GURPS Space, that'll give you lots of ideas for alternative drives and their effect on settings.

I used to have a GURPs library, but it took up too much shelf space. And when you have a book shelf full of books, then as a GM I would have to be constantly pulling books off the shelf to cover any situation I might deal with.

 

[Wil Mireu]

Pick up GURPS Space, that'll give you lots of ideas for alternative drives and their effect on settings.

I used to have a GURPs library, but it took up too much shelf space. And when you have a book shelf full of books, then as a GM I would have to be constantly pulling books off the shelf to cover any situation I might deal with.

...then get it on PDF? Even the 3e version is a goldmine for things like this. If you're into Scifi roleplaying or setting-building then IMO it's almost criminal not to have it available as a resource.
http://www.warehouse23.com/products/gurps-classic-space-4

 

[Lord High Munchkin]

Yes, GURPS 'Space' is a goldmine... I look at it constantly for aspects that the 'Traveller' game ignores or never developed. I have both the 3rd edition and the 4th, both are slightly different but both highly worth their salt.

 

[Tom Kalbfus]

The other drive mentioned in the core book is the Transport type, the instantaneous jump usually described as folding two points in space so they touch. The magic word 'wormhole' is often evoked. We see it in the movie Dune and the Dragonstar RPG uses a mass produced magic relic in their ships. Instant communications and the art of interstellar war is completely different as fleets appear at a planet's 100d limit. Starships need only spacecraft amenities and no low berths for passengers and crew.

I'm impressed we never hear anyone using this alternate in their campaigns.

What do you think of using the altered jump drive for Battlestar Galactica? You know the one where the Jump limit is 4 AU from the Sun and the Jump is instantaneous once you get there? I didn't like starships teleporting all over the place, including within the atmospheres of planets, sometimes teleporting inside mountains, and teleporting close enough to cause damage to a spaceship in one particular episode of the new BSG. I think jump drive shouldn't be something that you could use as a weapon or something from which you could mount a surprise attack! I don't think spending 5 days in jump space would be appropriate either for a BSG campaign, the setting is about a fleet where travel between the ships is common, so something like 5 days in jumps space without any contact with other ships in the fleet would be a major inconvenience.

 

[Infojunky]

Yes, GURPS 'Space' is a goldmine... I look at it constantly for aspects that the 'Traveller' game ignores or never developed. I have both the 3rd edition and the 4th, both are slightly different but both highly worth their salt.

I like the 2nd edition version the best of that book. Though I believe the 1 printing for 3rd edtion was substantively closer to 2nd edition than the later revised edition. But all of them are great references.

Note Dave Pulver is kicking around here, what I wouldn't give for him to give starships a once over (Hint he wrote all of the current Spaceships books for Gurps).

 

[Matt Wilson]

I think if I wanted to balance out the efficiency of a warp drive, I would consider making the M drives reaction engines and adapting the fuel guidelines from High Guard. But it might raise some issues with the viability of fighter craft.

To keep warp drives from completely shattering all the Traveller assumptions, you could borrow from the 2300 stutterwarp and say all warp drives have a max range of 2 hexes before the warp field becomes unstable -- on account of radiation accumulation or something. That keeps you from making a beeline across the sector. Gotta stop every two hexes to release that radiation into a magnetic field.

There's also the space drive in Fires of Heaven, which is a teleport drive that requires heaps of power and takes hours, even days to charge up. Range is limited only by the difficulty of plotting a jump.

 

[Reynard]

One thing not mentioned about a direct flight warp drive compared to normal jump drive is the ability to change course at any time plus no need to 'dogleg' systems just fly as the crow flies.

"What do you think of using the altered jump drive for Battlestar Galactica? You know the one where the Jump limit is 4 AU from the Sun and the Jump is instantaneous once you get there?"

Looking at the source for all things Battlestar, there is the hypothesis for the jump corridor. I infer that it is an instant crossover. The only limit is finding the proper neutral gravity point in a system so time in system is spent in scouting. That does raise the justification for a Transport drive. It makes sense in the series as you focus on the actions in a system rather than how fast you got there.

 

[Tom Kalbfus]

Getting there consists of reaching the Jump limit, which in our Solar System or a Star System with a similar Sunlike Star would be 4 AU or 3 AU from the habitable zone of that star. Assume the fleet accelerates at the rate of the slowest ship, which would be a maneuver 1, which would take 3.5 days to reach. Lots of time for interactions with the fleet. Basically starships are a substitute for buildings in a large town, the President of the 12 Colonies is the equivalent to a town mayor. So anything that could happen in a town of 50,000 people could happen here.