[Space] Technobabble for my new campaign.

[JazzJedi]

Great pseudoscience explanations! I will steal these! I especially like the reactionless thruster. Did you come up with this on your own?

[cvannrederode]

Originally Posted by JazzJedi

Great pseudoscience explanations! I will steal these! I especially like the reactionless thruster. Did you come up with this on your own?

All on my own. Some of the ideas have been bouncing around in my head for years. First time they've been put on paper (so to speak).

The short story is that it's meant to explain the "default" GURPS behavior of items, as sprinkled around, especially in Space and Spaceships.

The big thing that I brought from real life is Copernicium and Unhexquadium. They are both theorized as being on the "island of stability" (or the second island, in the case of uhq). Their half-lives are totally made up, since the isotopes listed haven't been seen yet. And the "magic" alloy of the two with it's miracle properties is also pure fiction.

One of my players is a PhD Astrophysicist who did his doctoral thesis on the R-process, so I'll see what he thinks of it.

[AlexanderHowl]

How do you prevent shuttles from becoming relativistic weapons that can crack planets? I would suggest capping maximum velocity to 20 mps × Acceleration. It would be more than sufficient to get off the ground but would prevent terrorists (or minor state actors) from using remote controlled shuttles to destroy entire continents.

[doctorevilbrain]

Wouldn't the rings wear out extremely quickly, and have to be replaced constantly, because they spin so fast?

[ericthered]

Originally Posted by AlexanderHowl

How do you prevent shuttles from becoming relativistic weapons that can crack planets? I would suggest capping maximum velocity to 20 mps × Acceleration. It would be more than sufficient to get off the ground but would prevent terrorists (or minor state actors) from using remote controlled shuttles to destroy entire continents.

You keep an eye out for them and hit them in mid flight with your own kill vehicles. Relativistic flight is bright, takes time, and once you're up to speed, you maneuver like a freight train. They smack something into you, and you turn into radiation. When you pair this with FTL travel, its really easy to mess up a KKV.

[cvannrederode]

Originally Posted by AlexanderHowl

How do you prevent shuttles from becoming relativistic weapons that can crack planets? I would suggest capping maximum velocity to 20 mps × Acceleration. It would be more than sufficient to get off the ground but would prevent terrorists (or minor state actors) from using remote controlled shuttles to destroy entire continents.

The RAW don't limit reactionless vessels other than saying they can't reach c. Most ships in my campaign will be using the "rotary" drive from spaceships, so they'll all have less than 1 g. Many will have only 0.1 g. Only a few will have standard (0.5 g per system), and only the military will have hot drives.

Yes, given enough time, you could get a small shuttle up to a faction of c, even with 0.1 g (0.1c in 350 days?) and do some real damage. The question is, how practical would this be, in the face of a TL9 or TL10 battlefield. How cost and time effective would it be compared to other weapons available.

FWIW: I remember a Man-Kzin Wars story, where the Humans had a ramship transit a Kzin controlled system at a high fraction of c. It's secondary weapons where metal rods dropped off, that would impact with nuclear weapon level energies.

[AlexanderHowl]

It would take 9.5 years for a 0.1g spacecraft to reach 0.98c (though time dilation would probably fiddle with the numbers).

[cvannrederode]

Originally Posted by AlexanderHowl

It would take 9.5 years for a 0.1g spacecraft to reach 0.98c (though time dilation would probably fiddle with the numbers).

That's according to someone watching them from a "stationary" point. From someone on the spacecraft, every second is five seconds in stationary space when going .98c.

[cvannrederode]

Originally Posted by cvannrederode

That's according to someone watching them from a "stationary" point. From someone on the spacecraft, every second is five seconds in stationary space when going .98c.

Hold on...I think I got that backwards...

<shakes angry fist at Einstein's grave>

[ericthered]

Originally Posted by AlexanderHowl

It would take 9.5 years for a 0.1g spacecraft to reach 0.98c (though time dilation would probably fiddle with the numbers).

According to this site (you have to put in distances, look at the max speed, and halve the time) 9.5 years only gives you .75 of c. for .98 of c you need 45 years. Which is not to say that .75 of C isn't scary. Its just no .98 c.

But .75 C gives you a fair amount of time to respond and protect yourself, especially if you've got FTL. And WWI, which was lost when national economies broke down, would be fought and the resulting civil wars over between launching your weapon and it arriving.