Interstellarplanetary travel

[spike]

OK so one thing I don't get is how exactly the interstellar travel works.

Engines are for orbit work and short range, Solar Sails are for longer range. If regular physics applies, Engines are high-thrust short-duration, Solar Sails are low-thrust sustained-duration, right. So you use Solar Sails to reach high delta-V and go long distances.

Is there any Faster Than Light (FTL) mechanism? Are Solar Sails used for FTL (which would be weird)?

I guess there does not need to be any FTL at all, because ST RPG takes place in some kind of very dense star cluster, where stars are only a few AU apart (AU = 150million km, 500 light seconds, a few millionths of a light year). The implied cruising speed of an ST RPG ship, one AU per week, is 500 light seconds / week or around 0.0057c.

If we assume Solar Sails are still reaction drives of a kind, and regular physics applies...

Taking the worst (highest thrust) case of moving only 1 AU, i.e. accelerate over 0.5 AU for 0.5 week and then decelerate over 0.5 AU for 0.5 week, your max delta V is twice the average V, = 1.16%c, so that implies an acceleration of about 80 m/s/s or around 8G.

8G is a pretty hefty thrust from a Solar Sail but I'm not going to quibble with the old Narvidian scientists. They're probably all dead, and dead or not, they'd eat my brains with pickle.

Since interplanetary speed in ST RPG is uniform, we can assume that over longer distances than 1 AU, there is no acceleration in mid phase, and a lower cruising speed is used, a speed that approaches 0.57%c as the distance gets longer. Or, conversely, that a less harsh acceleration is used on longer distance trips.

None of this includes relativity but it's not massively significant even at 1.16%c.

Of course, regular physics may not apply at all to the ST RPG universe, in which case all of this is moot.

[Cory Trese]

The ST RPG AU is an Astrochromm Unit, the Narvidian measure of space distances.

Void Space Reactor Engines create an inertia negation field known as a Void Space.

N^Other Nanoquant Coating creates a cross-Void matter bond (keeping the Solar Sails for sheering off and collapsing the Void Space Field.) Unfortunately the boundary between the inertia negation and "normal space" is extremely unstable.

Narvidian long range weaponry depends somewhat on exploiting this Void Space boundary for damage effects (micro-black holes, gamma radiation bursts.)

The remaining made up science ... I'm not sure about it. I keep trying to ask Narvidians but they seem to attack as soon as I mention any acronyms =)


PS: I assume Astrochromm Units (AU) are only used in space travel. On planet the Cadar probably measure everything in "length in torpedo" and the Rychart measure everything in "RH units" (Rychart Hat Units)

[Cory Trese]

spike -- you know waaaay more about this than I do. I just make up stuff!

[oldalchemist]

Spike, shouldn't you get a fuel discount for traveling in a straight line? Most of the fuel would be spent getting up to speed and getting down from speed.

[spike]

Ok cool so we have, to quote the old Space Opera pen and paper RPG (which I can quote by heart) a non-vectoring reactionless maneuver drive! Aka something that flies through space at constant speed (like a car, ship or plane). In a fine tradition from Buck Rogers and Doc Smith right up to Star Wars. I dig it.

[Kelvin Zero]

I use a Mystery Science Theater 3000 attitude towards science in any space games. All of the space games I have played either handwaved the science or had brain breaking features that I had to ignore to enjoy.

For Star Traders RPG, I never worried about how far away everything was. I assumed each planet had its own star system and the other planets of that system were unimportant for game purposes. Solitary stars seen on the map are there to be important to the story or for decoration.

The worst science I had ever seen in a space game was in Freelancer. While it did use jumpgates to get between star systems, it had the idea of using "spacelanes" through each solar system as the safe means of getting around. Traveling off the spacelanes increased your odds of encountering pirates. But the idea of spacelanes meant the planets could not revolve around their sun or the spacelanes would be obliterated. I had to fight to ignore the ridiculousness of the idea in order to play the game.