What do astrogators & engineers do? And, Fleet jumps
- Thread starter DFW
- Start date
If the jump requires hyper-pinpoint accuracy, then no ship could ever jump while it was moving, especially under combat conditions.
The rules state that if you come with 100D of another object, you are subject to its gravity well. The rules (in Core book) give the example of trying to jump from Earth to Mars with Sol in the middle. Once you hit the 100D limit of the sun you'd be yanked out of jumpspace. But beyond that the rules state simply the 100D rule for an object.
Which means you would, technically, need to take into account every planetary body of any significant mass in the system you jumping from to the system you are jumping too. The rules don't talk about it, but under this model, inbound and outbound jumps would need to take place above/below the plane of the ecliptic to minimize the affect of asteroids within the system on your jump bubble.
And the rules state that a ship retains its velocity and heading when enterig and exiting jump space. Which means that it is possible (and likely in some instances, especially for system assaults) for ships to be under power prior to jumping.
Therefore its likely that jumping does NOT require you to be within 5 mm from your calculated jump point. Within a few hundred meters should be more than sufficient for most any jump. And regardless, the rules have been generalized anyway to accomodate game play.
The rules state that if you come with 100D of another object, you are subject to its gravity well. The rules (in Core book) give the example of trying to jump from Earth to Mars with Sol in the middle. Once you hit the 100D limit of the sun you'd be yanked out of jumpspace. But beyond that the rules state simply the 100D rule for an object.
Which means you would, technically, need to take into account every planetary body of any significant mass in the system you jumping from to the system you are jumping too. The rules don't talk about it, but under this model, inbound and outbound jumps would need to take place above/below the plane of the ecliptic to minimize the affect of asteroids within the system on your jump bubble.
And the rules state that a ship retains its velocity and heading when enterig and exiting jump space. Which means that it is possible (and likely in some instances, especially for system assaults) for ships to be under power prior to jumping.
Therefore its likely that jumping does NOT require you to be within 5 mm from your calculated jump point. Within a few hundred meters should be more than sufficient for most any jump. And regardless, the rules have been generalized anyway to accomodate game play.
GypsyComet
Emperor Mongoose
phavoc said:
Which is to say, "right away". Earth flirts with Sol's Jump Horizon, so any jump sunward will need to do some normal space travel first.
alex_greene
Guest
Pilots would train in Astrogation skill, probably Computer, Comms and Sensors too, because for the most part all crew members have to sleep some time, and presumably every bridge post has to have a relief shift once in a while, assuming that we're not talking about a solo ship like a scout vessel.
alex_greene said:
Yes. Although, in system navigation (real space), is simple enough to have a computer handle at those TL's. Like an airliner, a merchie wouldn't have a dedicated Comm Officer. All pilots would have Comm-0 as part of their certification. Computer skill isn't needed unless you are programming. Interfaces would be MUCH better than what exists now. The Glass cockpits of today don't require "computer" skill as such.
DFW said:
Ah, I found it. Though not in Sector Fleet. It's in JTAS #24, in an article about what jumpspace is written by Mark Miller -
"The laws of conservation of mass and energy continue to operate on ships which have jumped. when a ship exits jump it retains the speed and direction that it had when it entered jump. Commercial ships, usually for safety reasons, generally reduce their velocity to zero before jumping. Such a procedure eliminates the danger of a high velocity collision immediately after leaving jump. Military ships and couriers often enter jump at their highest possible speed , and they aim for an end jump point which directs their vector toward their destination in the new system. Such a maneuver allows for constant acceleration in the originating system followed by constant deceleration in the destination system."
DFW said:
Sector Fleet (pg 79) has an explanation as well. All naval vessels are fitted with squadron jump systems which are slaved to a single vessel that initiates the jump. Fleets are linked to a more powerful system that controls multiple squadrons.
They also attach a variance (a small one, about +/- 1 hr) for a ship to emerge from jump. It says that small groups are more likely to emerge about the same time, but larger groups are likely to emerge with stragglers, which makes sense if they are adding in an emergence variable.
I was thinking about Jump accuracy roll and what it means game wise.
For non-misjumps we have:
1) Accurate jump = ?
2) Inaccurate jump = inner system somewhere
I'm assuming that one is aiming for a specific point of the 100D limit. A spot on a sphere of 100D in radius.
Accurate jump = Within a hemisphere of 1D of spot aimed for. For Earth this would be 8000 miles. Think of the 100D as a sphere and center the hemisphere on the point aimed for.
Inaccurate jump = As you may be aiming for anywhere in a system (not just an inner planet) I looked at the size of our inner system. This extends for ~2.5 AU from the sun. A diameter of 5 AU.
So, an inaccurate jump places you anywhere (except for jump shadows) within 2.5 AU's of your intended target. Or, within 375,000,000 km.
For non-misjumps we have:
1) Accurate jump = ?
2) Inaccurate jump = inner system somewhere
I'm assuming that one is aiming for a specific point of the 100D limit. A spot on a sphere of 100D in radius.
Accurate jump = Within a hemisphere of 1D of spot aimed for. For Earth this would be 8000 miles. Think of the 100D as a sphere and center the hemisphere on the point aimed for.
Inaccurate jump = As you may be aiming for anywhere in a system (not just an inner planet) I looked at the size of our inner system. This extends for ~2.5 AU from the sun. A diameter of 5 AU.
So, an inaccurate jump places you anywhere (except for jump shadows) within 2.5 AU's of your intended target. Or, within 375,000,000 km.
DFW said:
The MM traveller article talked about some of this. It mentioned that nav programs had to take into account the speeds and directions of the systems and planets that you were jumping from and towards. Careful programming had to take into account the relative velocities or else un-fun things could happen upon emergence from jump. The idea being that when you jumped you would arrive with a zero velocity relative to your arrival system (the concept was the same with military vessels, except they wanted to preserve their speed and vector relativel to the target system upon emergence).
So using your premise, the player would roll upon emergence to see just how accurate their navigation plot was. Most of the time it will probably be a normal one (+/- 10,000km is pretty reasonable). Failing the roll though, they should reference another chart (perhaps add in their nav skill as a DM on failure?). That will tell them how much they screwed the pooch plotting their course.
Using our system as an example, Maybe they missed the calculation on getting past Uranus and instead of missing the 100D jump shadow by 10,000 km to the 'left', they were 10,000 km to the 'right' and got pulled out of jumpspace in the far outer system. So now they can either try to make the trip on N-space drives, or refuel (fortunately they are at a gas giant), then maneuver and make another jump to their destination of Earth.
So if you want to make things complicated, go with some sort of chart that gives them a pure distance from their arrival target. Or, if you want to leave it more in the hands of the referee, come up with a simplistic 2D chart that gives distance (one million KM off target, ten million, etc and throw in a few 'pulled out of jumpspace at outer-system gas giant/planet/large planetoid/etc). Of course that means the ref might have to generate the system geography, but you could always do some hand wavium and say they are at a gas giant, it will take 2 days to maneuver in/refuel/maneuver out to a clear point to jump to target planet, or XX days under N-space drive.
But as a game mechanic, it would give the ref a lot of leeway to dump his players into adventures they were not planning on.
phavoc said:But as a game mechanic, it would give the ref a lot of leeway to dump his players into adventures they were not planning on.
Yep. That ~5 A.U. sphere in MGT for inaccurate jumps gives a GM lots of opportunity for adventure introduction. Also, given the odds of an inaccurate jump, pirates have a few more options.
