Best Rules for Building THS Spacecraft

[DAT]

I need to build some hard science space craft for a setting, and was thinking about using the THS spacecraft tech.

What set of rules do you find most user friendly and intuitive?
> Rules in THS Classic (plus the Metallic Hydrogen rule in Deep Beyond)?
> Rules in GURPS Vehicles?
> Rules in the GURPS Spaceships PDFs (though one of them was for THS spacecraft)?
> Something else?

[RogerBW]

Originally Posted by DAT

I need to build some hard science space craft for a setting, and was thinking about using the THS spacecraft tech.

What set of rules do you find most user friendly and intuitive?

I haven't yet needed more detail than I get from the Spaceships series (bearing in mind Smaller Systems), and it's a whole lot faster to run up a design than any of the others.

[Fred Brackin]

I haven't had occcaision to design many Transhuman Space ships. However, I will note that there is a unique element you get only in the series own design system.

That's the particle accelerators that did only radiation damage. When I saw the TS Spaceships book I noticed that they had been repalced with "conventional" damage-doing particle beams (though those do Rad damage ina ddition to d-Damage).

I never liked the Rad-only" acclerators and don't miss them but there may be soem purist out there who would.

[AlexanderHowl]

Most of the spacecraft in Transhuman Space have unrealistically high delta-v, so they will perform worse if made through the rules in Spaceships. In general, I think that the Spaceships rules are better than the Transhuman Space rules, though the economics of both are questionable. After all, if you can do commerical D-He-3 fusion, you can economically do DD fusion, which would allow you to produce massive amounts of He-3 without the bother of gathering it from the atmospheres of gas giants. In that case, the value of the Saturn System is the nitrogen atmosphere of Titan, as it would be $90,000/ton cheaper to ship nitrogen from Titan to GEO than to ship it from Earth's surface to GEO, and becomes even cheaper for everywhere else.

[RyanW]

Originally Posted by AlexanderHowl

After all, if you can do commerical D-He-3 fusion, you can economically do DD fusion, which would allow you to produce massive amounts of He-3 without the bother of gathering it from the atmospheres of gas giants.

Isn't the point of He-3 to avoid neutrons, which D-D would introduce back in?

[Anthony]

There's a pretty strong realism argument for rad-only particle beams, the ability to focus neutral particle beams without superscience is very limited and is generally dependent on achieving beams at multiple GeV -- and if you have the ability to generate GeV beams, you can kill things with radiation at a hundred times the range you can hope to kill things by burning holes in them, because they have penetration of several tons per square meter of shielding and most targets are actually more vulnerable to radiation than they are to burning holes in them (1 kilojoule of penetrating radiation is a dose of 1,500 rads and probably 3,000+ rem on a human target, which is 100% fatal; 1 kilojoule of thermal energy boils a fraction of a gram, which might be lethal if very precisely aimed and timed but is just a nasty small area burn if less focused).

This is less of an issue with charged particle beams because they tend to be more focused and lower voltage, but it's still the case that if you were to hit someone with a 5 MeV electron beam or something you can easily have the situation of 'outer surface of armor scorched but not penetrated; all tissue in a line passing through the body dead'.

This doesn't make for terribly appealing game play, though, which may account for it being tossed in Spaceships.

[Fred Brackin]

Originally Posted by Anthony

There's a pretty strong realism argument for rad-only particle beams,s.

It's not an argument "for" rad-only beams. It's an argumet against simple damage beams.

You might kill people surely with radiation even though it's in an unusually grisly fashion that could cause you be a pariah all over the solar system. The real problem is that you kill people _slowly_ with at least an hour bef0re they're disabled. That's much slower than any other weapon system ever deployed and could easily kill your enemies after they kill you.

[Anthony]

Originally Posted by Fred Brackin

The real problem is that you kill people _slowly_ with at least an hour bef0re they're disabled.

10,000 rads is plenty for fast disabling, 100,000 rads is more what you need for electronics. That's still not actually that much energy compared to burning holes in things. The real issue is that if you can build neutral particle beams at all, they're inherently much much better at radiation damage than killing things.

[AlexanderHowl]

Originally Posted by RyanW

Isn't the point of He-3 to avoid neutrons, which D-D would introduce back in?

They use DT fusion as the cheap form of fusion in the setting, which produces 7x as many neutrons per MW as DD fusion. Anyway, you could put an automated DD fusion facility on the Moon and harvest the He-3 and T every month. A 1 GW(e) DD facility would produce a few grams each of He-3 and T per second, meaning that the annual production of each would be over 100 metric tons.

[Kale]

Adding to the pile, Spaceships gives enough details so that your ship is consistent, but not so much detail that it takes hours to build a ship. I've created dozens of ships for a space campaign over the course of a day. The Spaceships system allowed enough detail that I knew what to describe to the PCs when they encountered each ship, as well as a general idea of what the internal layout would be like. It also made sure that I, as GM, was reminded of the specs of a particular ship whenever the PCs would encounter it, thus making them more consistent.