It is important to remember that the baseline assumption is that interstellar society was destroyed as a result of two, relatively equal factions going to war. The final stages included the release of A.I.-grade computer viruses that wiped data on a grand scale and made computer controlled machinery dangerous if not outright hostile.
At the end of each session, the player characters must return to the ship. This parallels the "each session ends with the PCs in town" rule in a fantasy-based campaign and is one of the major components of the campaign style. I originally thought about requiring the PCs return to the homeworld, but quickly realized that that would be much too restrictive on game play.
If the players fail to return to the ship, the DM rolls on sci-fi version of the Table of Doom, a random table describing what things happen to PCs who fail to make it back to the ship on their own. They'll make it alive, but probably not happy – it is a table of doom after all. Options include being attacked by a local predator or running afoul of locals, either a mugging, graft, or some other inconvenience.
What type of ship will the PCs be based out of?
The ship needs to allow for a number of faceless crewmembers for new PCs to step up from and replacements to be advanced from. With 5-6 players at a time, this will probably require a pool of approximately 30 crew.
Will there be non-crew on board the ship?
Possibilities for non-crew include passengers, gamblers, companions, and scientists (especially if the player characters have some form of government charter).
Assuming the ship is privately funded.
- Early missions are a search for funding/proof of concept.
- After a few successful trips, the possibility of having a research team assigned to the ship for a stipend. The ship still needs to trade, but this would be the beginning of a steady income.
- Later, the player characters could possibly be offered espionage jobs by various factions.
- There is also the possibility of getting bodyguard/VIP ferry jobs to other planets. Possible VIPs include: delegates, scientists, diplomats, wealthy people, and archeologists.
Status of Worlds:
The following is a brainstormed list of possible world types the PCs could discover, from the technology perspective.
- Space-faring: interstellar capability. This should be rare, with the PCs homeworld being one of, at best, three worlds capable of regular interstellar travel at the start of the campaign.
- Space-faring: intra-system only. Less rare, but still rare.
- Space-faring: orbital only. This society would still have advanced technologies, the lack of space flight possibly due to a slow rebuild of technology or a different set of goals set by those in charge. Other possibilities include societies with "Modern" technology levels or even a WWII era technology level.
- Advanced technology but no spaceflight. Similar to the above, but they do not have even orbital capability. Reasons for this could be a lack of the right technologies, a balkanized political structure, or simply no desire to return to space.
- Fallen to "Modern" technology, either stabilized or still falling.
- Rebuilt to "Modern" technology from a lower level.
- Fallen to WWII era technology, either stabilized or still falling.
- Post-apocalypse scavengers.
- Pastoral society with minimal tech, either due to conscious choice or a lack of the necessary resources to support any technology base (like a metal-poor world).
- Everyone is dead, either due to war (the original or something local) or a hostile environment that finally defeated the colonists.
- Recolonized by a previously unknown alien species.
- A new sentient species is developing in the ruins.