Tuesday, March 1, 2016

Psi Wars: A Technological Setting Part 1 -- FTL Travel

Hyperspace Exit
Without faster-than-light travel, we have no "space" in our "space opera!"  We enjoy Star Wars because it brings the exotic wonder of distant worlds right to our doorstep with the toss of a magical "hyperspace" switch.  We want Psi-Wars to do the same.  We want to visit distant worlds, and have alien invaders show up on our doorstep.  But while we're side-stepping the laws of physics, we still want our FTL to follow some consistent, repeatable rules, rules which we'll need to define before going much further.

GURPS Space has an excellent section discussing the particulars of FTL travel on pages 37 to 42.  In addition to discussing the possible options we have, it challenges us with a few specific questions:
  • How reliable is FTL travel?
  • How difficult is FTL navigation?
  • How fast is FTL?
  • How far can one expect to get in an FTL ship?
  • How much fuel does it consume? What are the economics of FTL travel?
  • What are the side-effects of FTL travel?
We need to answer these questions in a fashion that is not only true to our Star Wars inspiration, but that serve us well for our setting design.

FTL Travel in Star Wars

Star Wars seems to use hyperspace (GURPS Space 37-38) as its means of FTL travel.  The ship suddenly "jumps to light speed" and then vanishes from the universe.  At that point, it travels in a higher plane, hence the term "hyperspace," and in this higher plane, either the laws of physics differ, or its connection to "real space" allows a ship to circumvent a great deal of space to appear to travel more quickly.  If travelling through space is like an ant walking over the surface of an apple, then traveling through hyperspace is "tunneling" through the apple to take a shorter route.

Hyperspace raises additional questions:
  • How quickly can the drive be used?  Can it be used to escape?
  • How finely can the drive be controlled?
  • What is hyperspace like?
  • Can a ship in hyperspace be detected (and, a corollary, can it detect things in real-space)?
  • What happens when the hyperdrive fails?
These questions definitely have an impact on our setting. If the players can hyperjump at any time, to any place, with perfect precision, and cannot be detected, then warships will blink in next to a world, blast it to pieces, and then blink out again.  Battle lines become impossible and space warfare turns into mutually assured destruction.

We know a few answers to these questions from Star Wars, or that leap out at us from the premise of Psi Wars.  First, FTL travel is safe enough and reliable enough that it doesn't require a lot of paperwork, because Psi Wars is not a game where players regularly make maintenance rolls.  By the same token, fuel is largely a background concern.  This is the sort of setting where tramp freighters and scuzzy space-smugglers can afford to travel the galaxy with impunity, so FTL travel doesn't seem too expensive.  Likewise, Star Wars covers a galaxy, unless the people in the setting are rather presumptuous (perhaps the Galactic Republic is to the galaxy what the World Series is to the world), so there doesn't seem to be a limit on distance.  That said, there seems to be a definite divide between rim and core, so distance seems to matter in at least one sense.  Likewise, the nature of hyperspace doesn't seem to matter much beyond that it allows us to travel quickly from one location to another.  Finally, a ship in hyperspace certainly cannot detect what's going on in real space: Han Solo had no idea that Alderaan had been destroyed, and in Clone Wars, Amidala once jumped right into the middle of a battle without realizing it.

I have no ready answer to the rest of the questions, however.  Regarding precision, I've seen ships jump out of space inside of atmosphere or jump to lightspeed inside of atmospheres, but on the other hand, Star Wars often uses FTL astrogation as an excuse to keep a ship from just jumping away instantly, and quite a few sites and books seem to cite gravity wells as an obstacle for hyperspace travel.  Speed is similarly unclear: Distances seem to matter, but ships never seem to take longer than a few hours to get anywhere, but the actual time and distance involved in the travel are never explicitly mentioned on screen ("Parsec" is even used as a measure of time rather than distance).  Ships can't seem to detect other ships in hyperspace, and yet smugglers can make a living slipping past "blockades" that would seem to not be a problem if one can warp into a planets atmosphere undetected, and similarly, if a ship can just jump past your vessels to attack a colony and then warp out again, grand space battles have no point and nobody has borders, yet Star Wars has space battles and (presumably) borders. And while hyperspace travel doesn't seem to require a recharge or cost fuel, ships always look for harbors where they can stop, refuel, get some maintenance work done, etc.

So Star Wars only offers us a limited perspective on how to tackle our FTL.  It does, however, offer us some constraints we can use to create some rules of our own:
  • FTL should skip the boring bits, and bring us from one interesting planet to another interesting planet without dealing with the endless, pointless intervening space.
  • FTL should not involve finnicky book-keeping. If such book-keeping exists, the GM should be able to abstract it away or the players should be allowed to ignore it.
  • FTL should allow the players to reach any planet, but some planets should be harder to reach than others, or be "lost," allowing for treasure maps and investigations into hidden worlds, etc.
  • FTL should allow for dramatic escapes: they should be able to warp away in the heart of a battle, but not instantly, and once they warp away, they have truly escaped (at least for now).
  • FTL should allow for "space geography," things like trade routes and choke points, to allow for smuggling and war for control of certain "strategic systems."

Inspiration from other sources

Star Wars provides us only with a limited vision of FTL travel.  We'll have to fill in the blanks ourselves.  But why do all that work when we can just steal from other sources?

The Real World

FTL travel doesn't actually work (though I have my fingers crossed for Alcubierre drives), but Star Wars definitely draws its inspiration from the real world, specifically the warships of WW1 and WW2, like dreadnoughts and carriers.  Our ships will certainly need to follow suit.

Real ships require fuel, but the fuel isn't especially rare or costly (though we're willing to fight wars to ensure access to that fuel: It doesn't just grow on trees).  Getting fuel is just part of what a ship does when it reaches a port.  Ships also travel pretty quickly: A modern carrier travels around 35 miles per hour, which doesn't sound that fast, but it'll chug its way from New York to London in about 5 days, or from New York to Hong Kong in a little over 2 weeks.  Nothing in the world is more than half a month away, if we're determined.

However, access to the world requires access to canals and our travel is affected by weather.  A ship might be temporarily stranded thanks to a hurricane, or a part of the world might be cut off due to a blockade.  Star Wars regularly discusses similar problems.

Star Trek

In Star Trek, FTL ships move via warp.  They never leave the real world (they have a hyperspace of sorts called "subspace," but they use it to travel through real space, they do not enter it to travel), which means they get to experience all the cool swirly energy thingies that show up in deep space.  It also means people can detect them coming, allowing for battle lines to be drawn up, but there's no particular "space geography."  In general, this runs counter to what we want with Psi-Wars: We want to go straight to cool planets, not solve the mystery of binary pulsars.


Traveller was my first RPG experience, and one that should be familiar to most GURPS fans, as there was a GURPS Traveller for quite awhile.  In Traveller, travel occurs in "Jumps."  A jump takes 2 weeks, and requires considerable fuel.  How far the jump takes you depends on the power of the drive (Jump 1 moves you one parsec, two moves you two, etc).  In between jumps, ships will need to refuel.  This creates a space geography of a sort: Jump-1 ships will need to travel in relatively dense space, with systems no more than a parsec away, and it will need to refuel every parsec.  Meanwhile, a jump-6 ship could jump across a vast, 5-parsec gap of empty space without worrying about refueling.  This is closer to what we're looking for (skipping boring bits, space geography, etc).

EVE Online and Fading Suns

EVE and Fading Suns use Jump Gates.  Jump Gates connect to one another in predefined patterns: The Sol gate connects to the Alpha Centauri gate and the Epsilon Eridani gate, but not to Tabby's Star.  This means you know where an invasion fleet from Earth is going, and where they'll show up: At the gate.  It also means you can blow a gate (though they're huge and represent vast investments of resources).  But this means that a gate can go silent, and if its the only connection to a particular system, then that system is lost.  And likewise, dead gates can be repaired, coming back to life to allow strange, long-lost creatures to come pouring through.

This creates "Space geography" like the above, but I find it tends to focus travel.  You can only go from one system to another.  You cannot go haring off to random worlds of your own choice.  Your freedom is limited and constrained.

Warhammer 40k

Warhammer 40k, unlike the rest of the settings mentioned here, actually uses hyperspace.  Oh, but that hyperspace is nasty: It has storms and demons and drives people mad.  Ships lose their way in hyperspace, and sometimes never appear again, or appear hundreds of years later, or immediately but dead and hollowed out. Navigation through "the Warp" is treacherous in the extreme, and warp storms can cut off systems for centuries.  A less extreme version of this might serve us well.

Endless Space

Endless Space is a 4x space strategy game that I quite enjoy.  The exact nature of its FTL travel is a mystery to me (I believe it has "Warp drive,") but it's also irrelevant for this discussion.  For the purposes of gameplay, Endless Space has three kinds of travel: Strings, wormholes and warp.  Strings are the lines you see on the map above.  They represent the easiest, quickest path of travel.  Note how, like in EVE and Fading Suns, this might connect systems in an illogical way: Two systems might be close to one another spatially, but have no string between them, making travel between them difficult.  Wormholes require more advanced technology, are riskier and slower, but often connect "regions" of space that cannot reach each other via strings.  Finally, warp allows you to travel anywhere you wish, but more slowly.  Thus, if someone has blockaded a system by blocking all its easy entrances via string or wormhole, you can (if you're willing to invest the time) circumvent it by warping through more difficult paths.

Putting It Together

The Real World gives us several important baselines: Distant realms should be reachable in weeks, rather than months or years.  Star Wars itself suggests even faster travel times, and most travel between star systems seems to be spent at seedy space ports getting into trouble, rather than twiddling thumbs in your spaceship.  Travel is fast, measured in hours.  Downtime is longer, measured in hours or days.

Travel is definitely via hyperspace, and you can neither detect real space nor be detected, but going into hyperspace and coming out of hyperspace are obvious.  It shows up readily on any scanner in a system.

You can definitely warp into a star system near a planet.  So, let's make exiting hyperspace near a planet easy.  Perhaps even easier than exiting outside of a gravity well, making predicting your point of exit easy.  Of course, you can't just blink a few meters from the surface of a world, so there's a sort of "ideal point" around the same distance from a world as, say, the distance from the moon to us: Enough distance that warships in orbit can definitely intercept you, but not so far that you have to truck around through empty space to get to a world.

Traveller gives us the reason for our long downtime: We need maintenance and fuel. Fuel is readily available: I lean towards "refined hydrogen" but that would make gas giants more important than I really want.  Instead, our fuel should come from mines full of droids or oppressed laborers.  Uranium would probably be ideal, but that doesn't sound advanced enough, but we can say that it's toxic, costs about as much as jet fuel (SS 46), and a spaceship needs about one third of its stardrive mass in fuel per "skip," if the situation demands specifics. The fuel tank is part and parcel of the Stardrive (so we have compatibility with most ships in GURPS Spaceships).  A ship has enough fuel for 1 "skip" per "rating" of its star drive.  

Warhammer 40k gives us a fluid "ocean" of hyperspace.  We'll do the same. Hyperspace is subject to "weather," and it can shift and flow: What is difficult to navigate can become easy and vice versa.  It has "shoals,"  places that are hard to navigate, and "safe harbors" that are easy to navigate.  We need maps (treasure maps!) to correctly navigate to particular worlds.  Our hyperspace isn't so dire, though: Failure just means we're lost, and possibly pop out in the wrong system.  And a broken hyperdrive just won't let us jump, or it'll drop us out somewhere random.

Finally, Endless Space gives us the structure of our galaxy: There are "lines" or "currents" of easy travel that anyone can navigate.  The trade routes represent the safest passages, and since you can detect where a ship leaves, and you know the basic structure of the galactic travel lines, you have a good guess where he's going.  But, thanks to the idea of "warp," or more difficult navigational possibilities, you can never know for sure.  Finally, there are regions of space that are "connected," allowing for easy travel within that region, but travel to other regions tends to have "choke points," making for natural borders and strategic systems.

The Rules

Initiating FTL travel requires a Navigation(Hyperspace) roll and an optional Mechanic (Starship) roll. Navigation (Hyperspace) takes 30 minutes to calculate.  Appropriate modifiers for this navigation roll are the difficulty of navigating between two systems (-0 for "standard hyper lanes" and -1 to -10 for trickier connections; proper star charts can remove up to half of this penalty), time taken modifiers, "hyperspace weather" for -1 to -4 if any apply, and the GM may apply an additional -1 to -10 for "precision hyperspace jumps," such as warping in past a blockade, or warping far from a planet to escape sensors.  In general, warping too close to a planet is more difficult than warping too far away. Area Knowledge (Region of space) may be used as a complementary roll.  Failure on the navigation roll means that the players become lost, arriving far from their destination, or in another system entirely. Critical failures put them in very distant, unknown systems or drop them too close to a dangerous celestial object ("We're heading straight for the sun!").  If travelling through a variety of systems with different difficulties in a single "skip," always take the worst difficulty.

Hyperdrive engines require 5 minutes of charging (that is, being powered)immediately prior to a jump into hyperspace.  Players may reduce this by making a Mechanic (Starship) roll at a penalty based on the time taken modifiers, to a minimum of 1 minute for -8 (or, three turns of space combat).  Failure means the ship didn't jump and needs another 5 minutes to charge.  Critical failure disables the hyperdrive.

Hyperspace travel moves at about 30 light years per hour (or 10 parsecs per hour) per rating, for a maximum of 4 hours before one one "rating" worth of fuel is used up.  Thus, a rating-1 hyperdrive can travel 40 parsecs (120 light years) in 4 hours and then needs to refuel, while a rating-3 hyperdrive can travel 360 parsecs (1000 light years) in 12 hours before it needs to refuel.  Refuel costs and time are beyond the scope of these rules, but assume they take about day, and aren't terribly expensive, roughly equivalent to refueling a real world ship.  Note that, refueling aside, a rating-3 hyperdrive will cross a galaxy in about a month and a half.

You cannot interact with ships while in hyperspace, and they cannot interact with you, but anyone in a system can detect when, where and roughly from where someone jumps in, and people can detect when a ship jumps out, and have a rough idea of the direction its headed in.

For Characters

So what does this mean for you, dear player?  The following traits and skills might be useful:


3D Spatial Sense: +2 to Navigation (Hyperspace).


Light-Jumper: You may ignore up to -2 in time taken modifiers for either plotting your hyperspace route, or for jumping to light speed quickly.
Smooth Jump: Requires Navigation (Hyperspace)-16. You never have to roll Navigation (Hyperspace) for travel not directly related to adventure: Milk runs and bringing the characters to their homeworld is safe; travelling through a hyperstorm to a lost world or escaping from battle is not.
Smuggler Lane: Requires Area Knowledge (Region of space)-16. Choose one route between two systems in the region of space that you're familiar with. Ignore the standard Navigation (Hyperspace) difficulty for that route: for you, it's always -0.  Other navigational modifiers (Hyperstorms, time taken) still apply.


Area Knowledge (Region of Space): Complementary roll for hyperspace navigation.
Cartography: Allows your character to create star charts for the courses he is travelling, allowing him to travel through their again later more easily.  Success is worth at least +1, or more at the GM's discretion (usually worth no more than half of the difficulty of the course: a -10 course can become -5 at best).  Cartography is not necessary to use a star chart, but it can be used to glean additional information from a star chart that might not be obvious to others.
Mechanic (Starship): Allows for more rapid charging of a hyperdrive.
Navigation (Hyperspace): Used for navigating through hyperspace.

Space Navigator 25 points

This skill-set represents everything that might be useful to someone who is trying to get around through the galaxy. 
Advantages: 3D Spatial Sense [10]
Skills: Area Knowledge (Region of Space) (E) IQ [1], Cartography (A) IQ [2], Mechanic (Starship) (A) IQ+1 [4], Navigation (Hyperspace) (A) IQ+3 [4], Pilot (Starship) (A) DX+2 [4].

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