SWN Rules Explained: How Space Travel Works in Stars Without Number

Rules Explained

Aug 20

This episode of SWN Rules Explained looks at space travel in Stars Without Number: spike drives, how travel times work within and between star systems, and how ships find or lose each other through detection locks and chases. Brian uses the crew's escape from Causeway 3 in Eleven Rounds as the case study, working through what it takes to clear a switching station's defense drones and stay ahead of the Viridine Security Patrol once they're back in open space. He walks through the math behind spike drive ratings and drill checks, then explains how pursuit and evasion play out mechanically at the table.

[00:00:03] Brian: Access approved. Salutations, AdventureCast fans, and welcome back to another entry of Stars Without Number Rules Explained with me, Brian, the voice of the scapegoats Captain Thorn, Assistant Star Master, and occasional backup Game Master. While the main episodes of the AdventureCast are presented fiction first, this little series is designed to dig deeper and look more closely at Stars Without Number, the TTRPG system that powers our games, and talk about how the rules work and how they impact the gameplay and decision making that happens during our game sessions. Looking up rules or deciding how to adjudicate a conflict can slow down the narrative, but it's fun and it's useful to take some time to analyze how things work and why they were designed that way. If you're playing Stars Without a Number yourself and you want a little first-hand advice on how the rules work, or if you're just curious about the system and want to hear more about it, then you've come to the right place. The subjects for today's episode were picked based on the events of the most recent AdventureCast episode, Eleven Rounds. The crew has made their way on board the switching station, Causeway 3, but can they get the information they need and get out before the station's defense drones take them down? And will they be able to get away from this system before the Viridine Security Patrol is on top of them? If you haven't already listened to it, you should go check it out. Since we talked about building and customizing starships last time, this episode will be about space travel. We're going to talk about spike drives and how they work, traveling within star systems and between them, as well as ship scanners and space chases. The Stars Without Numbers revised rulebook has a whole section devoted to space travel and how it works, starting on page 110. Let's dig into this section and talk a bit about how it works and how it can be applied to our games. The first thing to understand is that all interstellar travel in Stars Without Number is possible thanks to a device called the spike drive. This is a part of a ship that allows it to travel the massive distances required to get anywhere in space within a reasonable amount of time. The History of Space chapter of the revised rulebook on page 121 goes into the lore of the default Stars Without Numbers setting and how spike drives came to be and what happened to them after the scream. If you're curious about that sort of thing, definitely give that chapter a read. But for this segment, I want to focus on what a spike drive does mechanically. For the most part, it's safe to assume any TL-4 spacecraft has its engines equipped with a basic spike drive, also called a level 1 or a tier 1 spike drive. This is what allows the ship to access and manipulate metadimensional space in order to move at speeds that are essentially faster than light. There's no special component that you need to buy, or extra mass or power rating that you need to account for when building a ship with a level 1 spike drive. It's just assumed to be a basic part of the hull. There are fittings you can buy to improve the rating of your spike drive, and we'll talk more about that later, but for the most part, any ship will be assumed to have one. Thanks to the power of this drive, the rules of Stars Without Number allow us to calculate travel times very simply. So a sector is an area of outer space that includes some number of stars and planets that are close enough together to be reached by spike drives. When starting a new Stars Without Number campaign, the Star Master would likely generate the sector by adding a bunch of stars to a hex grid that will serve as the setting for their adventures. A spike drive allows travel between stars by drilling through metadimensional space, the space that twists and loops around real space in such a way that the distances are not going to be one-to-one. Just because a star is physically close by does not mean that a spike drive could get there easily. Metaspace works significantly differently than real space, so sometimes a spike drive will take a vessel millions of light years in a single drill, while other times it'll take a really long time just to jump one star over. Because of this, it's better to think of a sector map as a sort of abstraction of metaspace rather than an actual map of the physical locations of those stellar bodies. Stars that are in adjacent hexes can be reached in a single spike drill. Improving a ship's spike drive rating will allow it to move more hexes in a single drill. A rank 2 drive can move 2 hexes, a 3 drive can move 3, and so on. To perform a spike drill to travel between stars, a ship must be on the outside edge of the star system, and it requires the pilot to make an int pilot check versus a difficulty of 7 to successfully map out and perform the drill. But this difficulty can be modified by a number of factors. Normally, the process takes about 30 minutes, but it can be shortened down to a single combat turn by adding plus 2 to that target difficulty. Traveling this way takes 6 days per hex traveled, divided by the rating of the spike drive, but the pilot can also accept another plus 2 difficulty to trim the course and try to get there faster, increasing their effective drive rating by 1 for this specific calculation. On top of that, the pilot must also reference the course rudder, which is a sort of map of the metal-dimensional currents that change over time. Trying to fly through metaspace with no directions at all is a fool's errand, and it will likely lead to disaster. Many explorers have made their living or ended their careers trying to gather and sell this sort of information. Powerful entities might even fiercely guard whatever valuable spike routes they could uncover. Having access to a rudder that's less than a year old is good enough for most drills, but if the data is any older than that, then the pilot's going to start incurring penalties to their spike drive role. There's a table of example drill modifiers at the bottom of page 111 in the revised rulebook. If the modifiers bring the difficulty down to 6 or lower, then the drill is simple enough that it won't require any roll at all. If the pilot attempts a drill and fails the roll, then they're going to end up having some sort of spike drill mishap. Roll 3d6 and consult the table of mishaps on page 111. Most of these don't result in the ship exploding outright or anything like that, but they can be quite dangerous. Sometimes it will mean the trip simply takes longer than expected, or it could mean ending up in a completely different part of space than they were aiming for. Whatever happens, it has the potential to change the way things play out in your game. Maybe the players wanted to go to a certain planet, but now they're stranded somewhere else. Maybe they were rushing to the scene of some great injustice to attempt to prevent it, but now they're a week late. When your party is planning to travel between stars, be sure you're prepared for things to go a little off the rails. Making a spike drill also consumes fuel. One drill consumes one load of fuel, so many ships need to visit a refueling station after each drill before they can make the next one. Each load of fuel costs about 500 credits. However, the Starship Fitting section on page 97 mentions a fuel bunker and a fuel scoop, two different ways to allow a crew to move through space without needing to make as many pesky stops for gas. Check them out. Using a spike drive to travel around within a single system is even simpler than that. As long as a ship has a functioning spike drive, they can move around to any location within a single system within 48 hours. A star master should identify the different points of interest in a star system and treat them each as distinct regions that ships can travel between. A planet is a region, an asteroid belt is a region, or a space station is a region. Even the star itself and the outside edge of the star system are regions too. Any stellar body and its satellites can be considered one region. For a ship to move from any one of these regions to any other region should take no more than 48 hours, divided by the rating of the ship's spike drive. You don't need to track which ones are adjacent and calculate the time that it would take that way, although a star master could require less time where they think it makes sense. Within any given region, it takes a ship six hours to get to any other location inside of that same region, again divided by the ship's spike drive rating. That means it should take no more than six hours to get from any location on a planet to any other, or from the surface of the planet to a satellite or the moon base. Again, the Star Master doesn't need to worry about precision when calculating these travel times, but they are allowed to modify it if they think something is close enough to warrant it. And just like with interstellar travel, if the pilot wants to trim the course to reduce the travel time, then they can do that by making a pilot check versus a difficulty of 9 to improve the effective rating of their spike drive by 1 for those calculations. Once your ship is in space, it's inevitable that your adventures will lead you to other starfarers and their vessels. So how do ships find each other, and how do they get away from each other? We've already talked about space combat in a previous Rules Explained episode, but in order to get into a firefight, the ships would need to be pretty close together. In order to find another ship in space, the observer needs to get what is called a detection lock on the target. If the ships are in the same region, the observer can attempt to get a detection lock by making an opposed int program skill check against the other ship's comms officer. This role is modified by the sizes of the vessels, and a table of the modifiers can be found on page 112. Just remember that the modifiers in the observer column are modifying the observer's roles based on the size of their ship, and the target column modifies the target's roles based on their ship. If the attempt to lock on fails, the observer can't try again for 24 hours. Once the lock is successfully made, the target can attempt to shake it by leaving the region. When they leave, the two vessels will repeat the opposed check to see if the detection lock remains intact. Having a detection lock on a ship means always knowing exactly where it is in space. This would allow a patrol ship to close in on a target ship from thousands of miles away, or allow pirates to monitor the movements of trade ships moving through their systems. Unless the observers take steps to avoid detection, the target knows when someone is locked onto them, and can make effort to try to break away and slip further detection. But unless they manage to get a lock-on of their own, the target wouldn't be able to tell if the pursuer was right on their tail. Once a ship has a target lock and is in the same region as its target, the pursuit can be handled by having the pilots make opposed int pilot skill checks. If the pursuers win, then they can close into combat range. Otherwise, the pursued can gain 6 hours of distance on their pursuers, modified by the difference in their spike drive ratings. They can use this to go to a new location within the region, or they can start trying to leave the region, keeping in mind that they'll need 48 hours of time to do so. Again though, the pilot can attempt to trim the course to escape sooner. If a ship manages to escape to the edge of the system region, they can start warming up their engines for a spike drill. And once they're out of the system, any chance of tracking them is gone too. Thanks again for listening, but we have reached the end of today's episode of Stars Without Number Rules Explained. I hope you found the information in today's episode useful or helpful for your own games. I'd love it if you could leave a like and a comment wherever you're listening and share the AdventureCast with your friends. If you like this sort of bonus content, then stay tuned for the next episode of Jeff's Star Master Logs coming out soon. While this segment focuses on the rules of the system, his segment is mainly about the design of our stories and how his and the player's decisions have impacted his plans. You can also check us out on Patreon at patreon.com slash darkstaradventurecast, where subscribers get access to new content two weeks early. I really appreciate all of the feedback and support we've gotten from all of you out there. And remember, as always, keep following that signal.