Need Help on "Semi-Hard" Classic SF Spaceship Design

[ericthered]

Originally Posted by Pursuivant

If there's interest in a fan-based SG GURPS supplement, I can create a dedicated thread for it.

That sounds like fun!


The books always make me laugh, because Dr. James White is the name of my father.

[Varyon]

Originally Posted by johndallman

Also, it seems unlikely that all the cultures in the galaxy use the same ship technology.

Depends on the setting. Deathworlders gave a pretty decent initial explanation of why, prior to humans getting involved, basically all the alien species largely used the same technology - they became members of galactic society once they figured out FTL travel, and it was generally easier to just adopt the (more advanced) technology used by the rest of the galaxy than continuing to develop their own. Humans, having evolved on Earth (arguably the most hostile life-producing planet in the galaxy), had a lot of crazy ideas that shook things up, of course (but even they initially relied on the tried-and-true, already-established technologies, although they divorced themselves from that reliance as quickly as possible). And it turned out that the technological homogeneity was largely due to a vast, ancient conspiracy suppressing certain developments, but I digress...

Originally Posted by Pursuivant

Functionally, I might have to go with reactionless drives, despite the fact that there are plenty of passages in the books about thermal and other effects from drives and all sublight spaceship maneuvers follow Newtonian physics.

I like to call this "semi-reactionless" - the drives use reaction mass, have drive plumes, etc, but they get physically-impossible efficiency out of it, and typically their drive plumes are far less energetic - and have far less range, such that an orbiting ship could just turn to have the planet it's orbiting directly behind it and go full-throttle without any ill effects on said planet - than they should be.

As for matching the performance of the ships in the source series (which I haven't read any of, nor indeed do I have any familiarity with), I'd suggest looking at a few of the ships you consider iconic (that is, those that your players will protest if they have markedly different performance than seen in the books) and base the behavior of your drives off of that. This may mean everything using the same drive technology but its efficiency goes either up or down as ship size (and thus the size of the drive itself) increases, or it may mean different technologies used in different applications (which again could be a size issue - maybe the drives used for smaller ships simply don't work on larger ones).

And if I wasn't being clear - absolutely, you should just create your own drives if nothing in Spaceships matches the performance you need.

[sir_pudding]

It seems like you just need a design switch that takes s suitable drive type and multiplies delta V by 10x or something per tank.

[Pursuivant]

Originally Posted by sir_pudding

It seems like you just need a design switch that takes s suitable drive type and multiplies delta V by 10x or something per tank.

That's one of the switches. Also having a Fusion Torch Drive which gives improved G and delta-v but which isn't as energetic as the Super Cosmic version.

I'll also have to brush off the Traveller 100-d Limit rule, which makes hyperspace travel impossible within 100 diameters of a large gravity well.

It fits well with the setting, since there are multiple references to having to avoid gravity wells when plotting hyperspace courses.

My points of reference are:

Ships need to travel some distance away from a planet or space station to enter hyperspace.

Ships appear to need to accelerate to some fraction of light speed to enter hyperspace.

Ships retain velocity, but not vector, when they emerge from hyperspace and need to decelerate if they're close to their destination.

For safety and to avoid overshooting, ships jump just a bit short of their destination.

Short range hyperspace jumps are tricky. It's easy to end up far from where you intended. At some point, it's simpler and faster to use sublight maneuver drives.