Relative motion of star systems in IMTU, what is means for the Express Boat Service Branch, and the legend (?) of Old Stinky and Mabel

[kilemall]

Re the no vee thing, I worked out an IMTU reason- the gravitic sensors have to have immediate local space mapped out eyes on during the generate phase. Since that is sensor short range re doggo for nav sensors or full range for primary sensors, the ship has to move only within that space doing generate than jump. On a practical basis without my complex rules, civilian ships have to be going vee of 15 or less and military 40.

 

[Grav_Moped]

I like the "Gravity-dimming" bit, bur given decades of play without it really having come up, I'll settle for "artificial gravity/inertial compensation isn't actually gravity for the purposes of Jump. Or since the artificial gravity effects are contained within the hull, it just doesn't distort spacetime outside the grid/bubble so it doesn't affect Jump.

 

[mike wightman]

I wonder if all passengers and crew are routinely strapped in for jump transition...

what happens in the unlikely event of shenanigans taking place and the ship crew deciding to jump without the strapping own order...

 

[whulorigan]

I wonder if all passengers and crew are routinely strapped in for jump transition...

what happens in the unlikely event of shenanigans taking place and the ship crew deciding to jump without the strapping own order...

Hopefully soup isn't being served in the galley or drinks in the lounge . . .

But then again kids might have fun - 57th Century space analog to a crazy-straw . . .

 

[DentArthurDent]

IMTU, we trust that Astrogators can account for relative velocities when they are capable of the amazing topographical feat of rendering our galaxy on a two-dimensional screen.

 

[Condottiere]

If you aren't moving towards it, how do you entre the rift in space and time?

 

[Badenov]

IMTU, we trust that Astrogators can account for relative velocities when they are capable of the amazing topographical feat of rendering our galaxy on a two-dimensional screen.

This is why you pay an Astrogator. If it were easy, anyone could do it.

 

[DentArthurDent]

IMTU, a ship has to stop accelerating (or decelerating) before Jumping. Since nearly all jumps are made within known space, Plotting a Standard Jump is Easy (+4) (modified by the jump distance). If the captain decides to jump while accelerating, the jump is more difficult (DM-1 per G).

Also, the owner’s manual suggests not making drastic or sudden changes to the artificial gravity, and avoiding power surges to the jump engines (so, no maintenance on the jump drives during jump). What happens if the crew decide to ignore this suggestion? It depends on what the GM is willing to create on the spot.

 

[yallambie]

This is a very good point.

To which I would add that the artificial gravity and acceleration compensation fields on a ship either :

1 being artificial do not interfere with jump the way "real gravity" does
or
2 are somehow compensated for by the jump drive - and yet the jump drive can not compensate for "real gravity"
or
3 are switched off as jump is initiated and may be safely turned back on once in jump space.

3 - Oh, that's just made the pet Ucellan Gerball more of a problem - sawdust floating around the cabin at each jump.

 

[Rupert]

Even though the description of Jump has always said that vector is preserved, the actual rules governing it suggest that it is not, that you jump in with your vector relative to that of the thing you're jumping in next to, and probably zeroed at that. (Why else would the procedure suggest you come to a halt at the 100D limit before jump?) The difference in vectors of nearby stars can be pretty huge, requiring days to compensate for, which tends to be far longer than it would take to reach the world you've arrived at. If your planning is poor, you're going to really make a splash an hour after emergence, no ocean required.

For that reason, I have just always assumed that your vector equals that of what you jumped next to, and you just somehow "steal" a tiny bit of its orbital or rotational momentum, or cool/heat it a tiny fraction of an attokelvin. Deep space emergences would preserve vector, since there's nothing close enough to steal momentum from.

Barnard's Star is moving very quickly relative to Sol - 142.6±0.2 km/s. At 1G that takes 4 hours to match. It's really not a big deal, something that adds (or subtracts) a few hours from a ship's entry or exit travel time. Alpha Centauri has a relative motion of 32.4 km/s, so under an hour at 1G will allow for that - and it's high-average for stars' motion relative to Sol.

I assume ships will generally match vectors with their destination, because they can see objects and avoid them then, whereas if you exit at a high relative velocity you might run into something before you can evade. I also go with TNE's assumption that a skilled astrogator will try to arrange the exit vector to be inwards in the destination system so there's no need to accelerate, etc. if the ship is in a hurry or uses HEPlaR or the like, where propellant saving is relevant.

 

[Rupert]

It's one of the "original sins" of Space Magic™.
It's a very obvious bit of handwavium intended to (game mechanically) engineer a way to "gravity wells don't matter" ... allowing all kinds of inconveniences (like balancing thrust vectors) to be "safely ignored" by gamers.

LBB 1-3 CT at least had the decency of grounding everything in newtonian motion and physics for the acceleration of space/star craft.
Then a later edition comes along and declares that liftwood contragrav is a Thing™.

Well, aside from air/rafts, and so on.