Jump collisions and velocities

By Dan Corrin ·

TML message #2147From bundle 171

T.L. Hayes brings up another point with jump procedures, one that leads to a
point that I was going to bring up after the 100 diameter limit got worked on
for a while.

> what would happen if a ship were heading out toward a safe jump point and
> suddenly another ship "appeared" (ie dropped out of jump) right in front of
> it?  Certainly neither ship could stop nor maneuver in time to avoid the
> impending collision.  It seems that there should be designated travel lanes
> for outbound and incomming vessels as well as intra-system travel lanes for
> boats doing interplanetary travelling.

1) Travel zones would be a haven for pirates (assuming no overpowering
   military force in the system - but pirates assume that anyway :-)

2) All ships are supposed to jump from "rest". Ie. you accelerate half way
   to the jump point, and deccelerate the other half, so your ship is at
   "rest" w.r.t. the system you are in. In the case sited above the ship
   popping out would have a near zero velocity, and the one approaching
   near zeo. This should be an easy collision to avoid. A meteor, space
   junk, or comet however...

3) The chance of this happening would be close to zero. Considering the
   number of jump points available, and the sizes of the ships. Rember also
   that the ship would appear no closer than "100 diameters" of the outbound
   ship whatever distance that works out to...

Not all jump points are equal! Consider your ship with a zero velocity
w.r.t. the star coming out of jump. If you are travelling to a planet,
your would want to be conveniantly situated. ie. If you come out "100
diameters" behind the planet in its orbit, your would first have to accerate
up to its orbital velocity, and then try to close in the 100 diameters.
You would want to come out ahead of the planet in its orbit, thus the planet
will do most of the work by moving towards you at a good velocity.

This is not reflected in the travel times, however. (Unless you use the
pilot/navigator performance enhancement rules from the starship oerator's
guide). Even then I'd have to check the math.

This next part is based on poor knowledge, but presumably, one would want to
travel retrograde (behind the planet in its orbit) in order to get to safe
jump distance quickly. Thus one would have all the arrivals on one side of the
planet, and the departures on the other, therefore "space lanes" of a sort,
and no collisions.

Now for the can of worms...(all references paraphrased)

The rules state that a ship entering jump space with a velocity, will retain
that velocity when exiting jump space. This is why all ships slow to zero
speed...
For stars with large proper motions jumpspace negates the effect.
Right! Which is it? Are velocities preserved, or are they not? If you assume
that they are normalized w.r.t. each sun, as I have done in the past, then
why, considering that you are moving to a point where gravity and thus
the effects of the sun are inconsequential on jumping, are they normalized?


I'm sorry if I bother some people with these types of questions, but they
are not just looking for scientific explanations of game effects. They
are contridictions in the rules that should be explained in a semi-rational
manner. (actually people bothered by these questions probably won't have
read this far anyways).

				-Dan Corrin

Dan Corrin, System Manager, Mechanical Engineering, UWO, London, Ontario
TML/CZ FTP site coordinator:     [email removed].        [phone removed]