Jumping from within atmosphere

zace66

Mongoose
Ok we had this happen... and im wondering how catestrophic this could be.

From what Ive read it seems they may be a temporal problem.. but are there any tables anywhere or descriptions as to what could quite possibly happen, best case/ worse case/ or has it happened to you?
 
Death?

Destruction of the planetary atmosphere?


Seriously bad stuff, which is why your supposed to be planetary radii away from planetary bodies when you Jump.
 
zace66 said:
Ok we had this happen... and im wondering how catestrophic this could be.

From what Ive read it seems they may be a temporal problem.. but are there any tables anywhere or descriptions as to what could quite possibly happen, best case/ worse case/ or has it happened to you?


I'm surprised to note that the rules area bit vague: jumping within 100 diameters is at -8 and deemed unsafe (MGT 141), but no note about closer jumps.

Old traveller rules (and possibly MGT, I may have missed it) had it that jumps within 10 diameters caused instant destruction of the drive, if not the ship. If they are within the atmosphere, they are certainly within 10 planetary diameters.

Hope that helps.
 
I'd simply follow the rules - Jump DM for within 100D is -8. :o So even with an Exceptional Success (DM+2) on the Engineering skill check (divert power) - there is a 0% probability of success!

- So the rules don't allow for a successfull jump - but don't mandate certain death - I like this...

Without average success on the divert power - they are automatically at an exceptional failure (same on less than 11 in any event) or a misjump if less than 9 (Referee discretion on time of death 8) ).

So this means an inaccurate jump at best. As the ref - this would be an appropriate time to apply the degree of success (also part of the rules) - i.e. no jump, majorly damaged ship, ship now part of small nearby moon (future tourist attraction), no ship...

Regardless of ground/air deaths - depending on the Government/Law Level there could be some serious 'issues' for such a stunt - even extending extra-system... i.e. a legal price on their heads!

(Personnally - I'd make them suffer :twisted: - but secret kudos for large cajones)
 
If nothing else, if there's oxygen in the atmosphere I'd say there'd be a massive explosion as the hydrogen in the jump bubble reacted with the oxygen.
 
(Though I'm not too keen on the whole description of Jump...)

The hydrogen is 'injected' into the 'parallel universe' to inflate the 'jump bubble' and then 'folded around the ship' - so any hydrogen reacting with air (assuming ignition) is trapped in the jump bubble - so the ship just gets a good pressure washing :wink:

Now the planet with the suddenly displaced air will be treated to a wonderfull sound and light show as the molecules of the surrounding atmo come together (at the very least that's gonna break some local ordinances! :D )
 
BP said:
I'd simply follow the rules - Jump DM for within 100D is -8. :o So even with an Exceptional Success (DM+2) on the Engineering skill check (divert power) - there is a 0% probability of success!

- So the rules don't allow for a successfull jump - but don't mandate certain death - I like this...
I do find it a contradiction though....

While in Jumpspace if you get within 100D of a gravity well... *pop* you come out of jumpspace.

But within that 100D limit you can still form the jumpfield and enter jumpspace.

One thing says the jumpfield can exist in the 100D limit yet the other one says it can. I would tend to say the field couldn't form at all.


The book also says failing the role results in an "innacurate" jump (minor setback) and actually getting a result of 0 or less is an actual misjump.

Now with an Engineer Skill of 3, an EDU mod of +2 (EDU 12-14) the Effect of the 'divert power' roll can be as high as 9, negating the -8 for a jump within the 100d limit. Even if the average die roll of '7' is gotten on that roll then the effect is +4, cutting the 100D penalty in half and significatnly reducing the chance of a misjump. I think the chance of a misjump, if you could get the jumpfield to form at all, should be much higher.

Actually, maybe the "inaccurate jump" should be "jump field does not form" and "miss jump" should mean "you somehow go the jump field to form but boy are you screwed now".

Core Rules pg 141 said:
Roll 2d6 and add the following DMs. If the result is 0 or less, the ship misjumps (see below). If the result is 8+ the Jump is accurate. Any other result is an inaccurate Jump (which is only a minor setback).
• + the Effect of the divert power Engineer check
• –2 per Jump drive hit
• –2 for using Unrefi ned fuel
• –8 if still within the hundred-diameter limit
 
GamerDude said:
One thing says the jumpfield can exist in the 100D limit yet the other one says it can['t].

Actually it says that if you're in jumpspace and you come within 100D of a large body, you'll precipitate out of jumpspace. If you start in realspace and try to enter jumpspace within 100D of a large body, you can still attempt a jump but you'll have a significantly increased chance of a misjump.

One rule applies to jumpspace, the other rule applies to realspace. There's no contradiction - it doesn't have to work symmetrically.
 
I know what the rules say,

And to me jumpfield is a jump field... so to me there is a little dysfunction...

like putting a Earth-like world in orbit around Jupiter wouldn't click for you.
 
GamerDude said:
...Now with an Engineer Skill of 3, an EDU mod of +2 (EDU 12-14) the Effect of the 'divert power' roll can be as high as 9, negating the -8 for a jump within the 100d limit. Even if the average die roll of '7' is gotten on that roll then the effect is +4, cutting the 100D penalty in half and significatnly reducing the chance of a misjump. I think the chance of a misjump, if you could get the jumpfield to form at all, should be much higher. ...
Ouch - you're right GamerDude - I used Task Chain DM's rather than + the Effect of the divert power Engineer Check - so yeah, that could allow for a success on a Jump within 100D...

Which does put some emphasis on the skill level/stats of the Engineer - allowing a really good engineer to assure success...

That may seem a little outta wack - but then, nothing specifically forbids the Jump from happening even on a planet's surface (or in a space dock for that matter!)... Given the Core book's descriptions the gravity problem is not a show stopper, just an issue, especially since a certain amount of randomness (time, placement) is a given.

As to the 100D precipitating early re-entry into normal space - EDG addressed that well - except the problem, that based on the book's example, one might normally expect to instantly re-enter normal space (being within 100D limit). Reconciling this with the example - one could say that a successful (if the dice allow) Jump within 100D still would only allow one to Jump within the 100D (closer or farther...) - i.e. one could Jump from the surface, but at best still endup within orbit of the planet or atmo (or right back where you started a week before).

I think another intent being that Jumps do not neccessarily occur in a straight line, but have to be planned and occur in such a way that jump 'path' does not fall within 100D of any intervening mass...

So, the example of Earth to Mars with the Sun in between isn't extremely clear - unless one assumes that these paths cannot curve so much as to, say, avoid the sun in a solar system. But can curve enough to avoid intermediate star systems and smaller bodies.

Of course, this ignores the fact that traveller rules don't provide a (simple) way for addressing orbits.
 
BP said:
As to the 100D precipitating early re-entry into normal space - EDG addressed that well - except the problem, that based on the book's example, one might normally expect to instantly re-enter normal space (being within 100D limit).

Again, it's not symmetrical - the issue of jump precipitation only exists if the ship is already within jump space and approaching the 100D limit from the outside.

I visualise it like this: You're probably familiar with the 'rubber mat' analogy of spacetime, right? Big masses like stars make dents in spacetime (like cannonballs on a rubber mat or mattress) - that makes a slope on the surface of the mat around the object, and that slope is gravity (steeper slope = higher gravity).

Imagine now that you've inverted that (i.e. you're "underneath" the mat). That's how jumpspace sees realspace in this analogy. So now, instead of dents, you have hills where the masses are. Still with me?

Now, let's say jump is only stable in the flatter areas of the mat/spacetime, far from big masses. If you're already in flat space, you precipitate out of spacetime when the slope of spacetime (caused by the mass) is greater than a certain value. In this case, it's not a consistent slope value because it's based on distance, not gravitational field - it's the angle of the slope at 100D from the object. Essentially, a ship in jump can be imagined as flying at a (very very low) constant height relative to the flat surface of the inverted mat (and very close to it) - when the slope changes, the path of the ship intersects the sloping surface and precipitates out of jump into realspace.

Now, when you're already within the 100D limit and trying to jump out of it, you're already in a gravity field (non-flat spacetime). That's what makes it harder to jump out - in jumpspace terms, you're on the sloping surface of a hill, not on a flat surface (which would be ideal/preferred) far enough from any masses. But it doesn't make it impossible, it just seriously complicates up the calculations (beyond the ability of OTU tech to calculate), and thus produces unpredictable results such as misjumps.

(this would be a lot easier to understand if I drew a picture, I think...)
 
EDG said:
...(this would be a lot easier to understand if I drew a picture, I think...)
Nope - that's the way I picture it too - I just got side tracked and went down my own sloped path... Thanks for pulling me out :)

To boil it down (obviously not something I excel at :wink:) -
Jumping out of a 100D 'matter-gravity' well often has unpredicable results
A really good engineer might be able to compensate for this
A Jump path that intersects a 100D 'matter-gravity' well typically causes 'early' re-entry to normal space (in terms of position).

Also -
Successful (even inaccurate) Jumps always take ~1 week
Misjumps may take varing amounts of time (though generally involve destruction) - refs discretion.
 
I get the dents in space, curved space etc...

I just find it hard to accept the creation of something inside the 100d limit that can't exist when it starts outside that limit and reaches it.

I know this is not the best example but it should work: It's like saying a piece of limestone immediately dissolves when it hits the surface of a pool of acid... but if the same piece came into existence inside that same pool of acid it could survive until removed.

I know what the rules say and such (I quoted them in my first post this thread), and understand what EDG is saying (the basic concepts are something I do understand). It just doesn't jive in my head.

Of course, since I don't have a sensible replacement, I will use the rules as written.

EDG, if you can do a drawing and post it to the web I'd be happy to look at it.
 
GamerDude - how about reversing analogies - picturing that rock being throw over the water (by a magic hand)...

The rock flys just above the water till it comes down...

If there is a high enough ripple - the rock 'hits' it and sinks (100D matter-gravity)

If one throws the rock out of such a ripple and makes it clear - only another ripple will take it under

(I understand the tendency to say the rock then couldn't come out of the ripple - like gravity - that's why I use 100D matter-gravity, since its not really 'gravity'. And ripple isn't exactly what I want - maybe more like a bulge sticking above the water... sorta an inverse of the picture EDG was painting...)
 
I follow you...

It's just how the logic works in my head.

Hopefully I'm not coming across as intentionally contrary or something. It's just something I keeps me scratching my head when I think about it.

I am enjoying the discussion and appreciate it
 
This a great topic - glad I started it.

Anyway - my players engineer successfully shunted the power across and charged up the crystals, giving a +1, with the pilots poorish roll, the +1 and the -8 they scored a net +1, reading up this is just a simple misjump apparently.

But as said earlier - oh yes they gonna suffer... quite a shame as the engineer has lovinglu just replace both manoeuver drives, and as they are right next to the J-drive...and power plant.... well lets just say its gonna be expensive.
 
zace66 said:
... just a simple misjump apparently.

But as said earlier - oh yes they gonna suffer... quite a shame as the engineer has lovinglu just replace both manoeuver drives, and as they are right next to the J-drive...and power plant.... well lets just say its gonna be expensive.

Good news you guys - the jump worked and your ship was not destroyed and you're all alive and well... uh... tho' the J-Drive sorta went and took out the M-Drive and the Power Plant

But no worries mates! Power Plant is easily fixed and emergency is work'n fine... ah... plus somebody be pick'n y'all up real soon

- especially when the news of what you did arrives! :twisted:


[Hint: Adventure 2: Prison Planet]
 
Yeah, looking about, this is obviously one of those areas where MGT and CT differ -at least by omission. here isn't any reference to the 10 diameter limit (inside of which one is destroyed) that I can find (yet). The -8 covers it well enough for most situations I think, if one wants to be rules pure.

Me, I like the idea that one cannot jump in an atmosphere or from the ground for a variety of reasons. Still, the "horrible explosion" isn't good either -I've learned from bitter experience never to give players a suicide bomb, or create a new terror weapon.

So, my call is that inside of 10 diameters, more or less, you stay where you are, and the drive systems slag down. expensive and useless.

I've got some ideas as to why, but that's another thread...;)
 
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