Travel Mechanics for a Science Fiction Game

[Solfe]

I am working on a science fiction role playing game. One of the features of the setting is very fast travel, but never faster than the speed of light. This is my one big handwave, I am not particularly interested in explaining how it works. I guess it is a type of wormhole, but I would be just as happy calling it magic. My purpose in having such a device is to avoid unbelievably high tech engines, body smashing accelerations and time travel.

In order to travel quickly, the characters enter a machine called The Orrery. Each major planet has at least one Orrery entry point, either in orbit on a space station or on the surface of the planet, if possible. The properties of the Orrery are such that each trip takes exactly 20 hours, no matter how far or close you are traveling. Passage is one way, so a traveller must cross the threshold of the door on the other end before turning around to go back to the place they left. A round trip journey like this would take 40 hours. Another property of the Orrery is crossing the threshold of the doorway causes the person to vanish. The will not be seen again until 20 hours pass and the door is opened on the far end. The traveller can open the door themselves, it isn't locked. Interestingly, there is a window of time where multiple people can enter and travel as a group. It's short, like 30 seconds. Otherwise, everyone travels alone.

Obviously, using the Orrery to commit crimes in one place and escaping to someplace else won't work. A radio message would outrun the escapee by a good margin.

People's sense of time in the Orrery is highly subjective, some people would say the trip was minutes long while other experience the full 20 hours. This almost seems like a user choice, but is vaguely unpredictable.

With such a device, would there be any possibility of actual time travel?

[Roger E. Moore]

I would avoid time travel unless you have a thoroughly worked out system to go with it that either does not affect causality or makes use of alternate histories. PCs will take advantage of it instantly. There have not been any satisfactory time-travel games that I am familiar with, and I've played a couple. I assume the Orrery does not interact with gravity. Travelers could exist a sabotaged Orrery into a deathtrap, killing everyone until it is fixed.

How was the Orrery created? Is a special material needed to operate it? How has it affected the known inhabited universe? Did anyone discover the secret of the Orrery before humans did? (Just questions to consider, don't need to answer to me.) Could Orrerys fail en masse? Is this some kind of quantum-relativity effect (just junk words, but meaning it was created in a lab and not built in space.)

[Solfe]

I would avoid time travel unless you have a thoroughly worked out system to go with it that either does not affect causality or makes use of alternate histories. PCs will take advantage of it instantly. There have not been any satisfactory time-travel games that I am familiar with, and I've played a couple. I assume the Orrery does not interact with gravity. Travelers could exist a sabotaged Orrery into a deathtrap, killing everyone until it is fixed.

How was the Orrery created? Is a special material needed to operate it? How has it affected the known inhabited universe? Did anyone discover the secret of the Orrery before humans did? (Just questions to consider, don't need to answer to me.) Could Orrerys fail en masse? Is this some kind of quantum-relativity effect (just junk words, but meaning it was created in a lab and not built in space.)

I'm trying to avoid time travel, so I don't really want to say how The Orrery works other than you can't use it like a time machine to the past. I'd be happy with a magical device so long as this has no obvious implications for time travel.

Apparently, it is a singular item, either really big (the size of the solar system) or more like how we say "The Internet" is big. If one fails, they all fail. People inside The Orrery during a failure sense nothing, they simply travel to the destination as if nothing happened. They obviously can't use it to go home, but failure not inherently dangerous. You can't be trapped inside. You can hide in the exit area, but once twenty hours pass, people can see you hiding there. It's no different than hiding in the jetway at an airport and equally odd. It would probably end in you being escorted out or being checked out for physical or mental problems. You can't really do anything in there that would impede it's use. Not even get in the way, since you can't see other travellers.

The Orrery is kind of inert, I guess it could catch fire like a skyscraper or something. The Orrery requires no special equipment to operate once built. Entering one is about as a interesting as walking down a long hall, except that the exit door simply appears at the end of the journey. In the case of a space ship traveling via The Orrery, people looking out the windows see whatever was happening the moment they entered. It's like a freeze frame. The background stars don't seem to change at all until they arrive, then the simply change in the blink of an eye.

Apparently, the Orrery shifts momentum and inertia, gravity somehow. Ships and people exit The Orrery at speeds that are "normal" relative to the device itself. I suppose someone could enter one end of the device so fast that on exiting, they'd traveling at an unsafe speed at the destination.

One day, the technology to make it became obvious and it was done in less than one human lifetime. Technology in this game is fairly high, but aside from this one physics bender, the characters live in our universe. There is no Orrery to places people can't reach by rocket or ion drive. Everyone wants to make an Orrery on Alpha Centauri. But so far, it's all a pipe dream. Kind of like how we talk about jetpacks. The Starshot Project is a historical event in this game, but it was also a non-starter due to the minuscule size of the vehicle.

There is no real alternative to it, other than sup'ed up version of stuff we have today. Safer, more reliable and longer duration that what we have, but there isn't a massive shift in technology other than this one item. Someone could hop on a Ion ship to Mars, but it would take much longer than 20 hours. Imagine how easy it would be to live on the Moon or Mars if Earth could forward along anything you need in 20 hours?

One obvious flaw I can see with such a device is using like a heat sink. You generate heat near the entrance, project it into the device and it vanishes for 20 hours before ending up someplace else. The other issue I see is the ability to hop forward in time.

[Chuck]

Can you send water from the bottom of a mountain to the top and then let it run back down turning generators as it goes, getting something for nothing?

[Solfe]

Can you send water from the bottom of a mountain to the top and then let it run back down turning generators as it goes, getting something for nothing?

I never considered that option, but I don't think it would work. The Orrery is basically a self-contained one way tunnel or a hallway. Once the door closes, the space inside The Orrery is self-contained and all travel, no matter how far takes 20 hours (however, the furthest extent of the device can take you is less than 5 or 6 light hours away). Theoretically, you could put so much pressure inside the pipe the water would move to the other end via momentum. Or you would have to put pumps inside The Orrery to keep it going at a desirable speed. Since time is subjective inside The Orrery, the first option wouldn't work because you don't know what fraction of 20 hours the water would experience on its travels. At least with pumps you can't have the water exceed the speed or force that the pumps could provide in the given time.

If you made the whole thing vertical, then I guess you could drop water from one end to the other, which would be no different than hauling the water to the top of cliff and doing the same thing. Except there would be a 20 hour delay due to the fixed travel time and the water would no longer be on the same planet. You can't run an electrical wire through the thing because the doors need to close to operate and whatever was in there vanishes while in transit. Assuming you wanted to give someone else energy, you'd be better off transporting a whole nuclear reactor through it to be built on the other end.

The only hole I can think of is displacing energy into The Orrery, say waste heat, and having that energy appear somewhere else after a long delay. It would solve one person's problem while creating a problem for someone else. If The Orrery had a passage from the Earth to the Moon, people on the outside of The Orrery would have about 19 hours and 59 minutes to think of a solution to whatever problem that much heat would cause. Radio goes faster than travel through The Orrery.

Basically, I am trying to convince myself that a smarter, wilier person than I couldn't easily exploit this "feature" and turn it into a "bug". Time travel was my biggest concern.

[The Backroad Astronomer]

Hope you don't mind this intrusing Solfe.
But I am trying to work a sci-fi story but I am just using hyperspace to reduce the time in travel. Basically the more energy used in the hyperspace engines the deeper in hyperspace and shorter the distance and I do have time travel.

Your system sounds like a modifed wormhole with a fixed amount of time.

[Chuck]

How much power is required to run the Orrery? If you move something from the earth to an outer planet do you have to pay for the potential energy that it gains by being farther from the sun?

[Roger E. Moore]

I ran a Traveller SFRPG campaign in which the players kept jumping off the map, forcing me to generate new systems all the time.

In this light, I would severely limit the ability to jump forward in time, or else the PCs will jump a million years at a time to watch you scramble to build new Earths.

[Solfe]

How much power is required to run the Orrery? If you move something from the earth to an outer planet do you have to pay for the potential energy that it gains by being farther from the sun?

Hmm. I don't know how much power. I didn't think it though that much. I did consider the the potential energy aspect then thought, "Gee, that's really complicated. I'm going to ignore it as much as I can". This thing operates in the same way a The Way operates in Greg Bear's Eon series, or like a Stargate from the movie or TV show. It's power by plot.

The "real problem" I am looking at is this is a game to be played by a small group of people (or even just one) in a choose your own adventure style campaign. I have been looking at various books which work somewhat like this. One of the most disappointing endings for a game like this is when the player or player think they know all of the rules at the outset of play then the author drops the line "You discover a time machine! It works! You can do whatever you like! You win the game!" Players don't like that sort of victory because they had been relying skill to get to that point only to have all of that upset by the addition of an item that isn't constrained by the rules they know. Judging by some of the surveys and questions I have asked potential players, they would rather cheat to avoid such a "victory" than accept it.

I think the solution to that is to flat out tell the players, "there are no time machines" and then spell out a specific goal that can be reached in a variety of ways to end the game. The Orrery is just a plot vehicle, which happens to always be accessible to the players. It can't be the mechanism to "cause victory". Of course, since it is a branching story, there could be many goals, or one goal swapped for another, but the magical time machine would never be one of them. The players are already being asked to suspend their disbelief to get very fast, but limited space travel. You can't push them too much harder.

[Solfe]

Hope you don't mind this intrusing Solfe.
But I am trying to work a sci-fi story but I am just using hyperspace to reduce the time in travel. Basically the more energy used in the hyperspace engines the deeper in hyperspace and shorter the distance and I do have time travel.

Your system sounds like a modifed wormhole with a fixed amount of time.

It is. At least, I believe it is. However, being a game, I don't really have to explain how it works in any significant way.

Like Chuck mentioned, it's not possible to use The Orrery to gain energy. If you could do that, there would have to be a configuration where the user could pump up the energy/speed of an item to travel to other stars. Sort of like a gravitational assist on a very large scale. That isn't really allowed in the scope of the game because the setting is "only" our solar system.

[Solfe]

I ran a Traveller SFRPG campaign in which the players kept jumping off the map, forcing me to generate new systems all the time.

In this light, I would severely limit the ability to jump forward in time, or else the PCs will jump a million years at a time to watch you scramble to build new Earths.

This is why I created the threshold rule. You have to step entirely out of The Orrery to use it again. It only travels to fixed places and the time limit ensures that a radio message can out run you. Messing with the authorities in one place simply ensures that the authorities on a different planet are really, really ready to catch you. It's a non-starter, like robbing a vending machine with a banana. Basically, it can't happen and if attempted it you'd simply look silly instead of getting a bag of chips.

I made time subjective in The Orrery so the players would learn to ignore it or not see it as a resource. I made the duration of use fixed so that the players don't try to exploit it.

[Roger E. Moore]

I used to tinker with an idea in SF stories in which jumping from star to star could only be done with an enormous accumulation of velocity before turning on the jump drive. People would have to dive in very close to the Sun to build up enough energy to jump, making it very dangerous.

[Roger E. Moore]

I made time subjective in The Orrery so the players would learn to ignore it or not see it as a resource. I made the duration of use fixed so that the players don't try to exploit it.

Playtesting will tell if this works, but you've got the idea.

[Chuck]

I ran a Traveller SFRPG campaign in which the players kept jumping off the map, forcing me to generate new systems all the time.

In this light, I would severely limit the ability to jump forward in time, or else the PCs will jump a million years at a time to watch you scramble to build new Earths.

I vaguely Traveller. That's the game where your character can die while being rolled up, right?

[Solfe]

I vaguely Traveller. That's the game where your character can die while being rolled up, right?

Yes, that's right. You can have a bad time before you start to play.

[Noclevername]

Hmm. I don't know how much power. I didn't think it though that much. I did consider the the potential energy aspect then thought, "Gee, that's really complicated. I'm going to ignore it as much as I can". This thing operates in the same way a The Way operates in Greg Bear's Eon series, or like a Stargate from the movie or TV show. It's power by plot.

Just invoke vacuum energy. Call it a "free lunch" just to annoy the engineers.