"jump masking" based on gravity

[kaladorn]

It's interesting that you mention the point in passing, but mainworld selection may have (in a rational universe) been heavily driven by this very fact, depending on your JLimit model.

If your JLimit model makes a slightly less optimal world the best for interstellar commerce, that might easily become the trading hub (and perhaps later social and technological hub) of a system.

Interesting idea. Be interesting to somehow embed this knowledge into system generation rules.

 

[TheEngineer]

Hi !

Sorry Chris, but there is no link on the homepage to the Traveller files. I will fix that ASAP.
CYou will find the newest version (Build 27) here .
The is a dropdown list on the upper right, letting choose 0 to 2 for the 100D mode.
0 is just diameter way,
1 is the gravitational accelaration model
2 is the derivation/slope model.

And Thomas, perhaps we could convice Stuart Ferris to incorporate some of these thoughts into his H&E 2 System module....would be a good place for that.

Regards,

Mert

 

[RainOfSteel]

Originally posted by TheEngineer:
Hi !

Sorry Chris,[...] here .

Thank you!

Originally posted by TheEngineer:
And Thomas, perhaps we could convice Stuart Ferris to incorporate some of these thoughts into his H&E 2 System module....would be a good place for that.

What was System View written in?

 

[TheEngineer]

Its just (very dirty) VB 6.0 code, but I turn it to VB.Net shortly.

 

[RainOfSteel]

That would match up with what Stuart is writing H&E 2.0 in.

 

[TheEngineer]

Yeah. I regret, that I started the project with "old" VB6.0 . But programming started very spontaneously and I was not keen on installing Visual Studio .NET then....

As Stuart noted in his HE2 yahoo group, he plans to do something related, a kind of 3D system viewer using DirectX libs. This would be very cool, I guess.

 

[kaladorn]

It shouldn't be tooo hard to port. VB.NET has a porting tool and you only have to re-engineer about 40% of your code (from my experience of us doing this at work on about 6 large apps). <*grin* - never said it wouldn't hurt...>

 

[Straybow]

The idea of gravitational sheer or stress has been put forth as a credible alteration to 100D rule.

See Stuff Online (Jump Drive).

This page also incorporates MT difficulty levels with distance instead of a fixed limit.

 

[Tobias]

For stars:

Solar 	limit/metres	limit/AU
masses
15	4.46179E+11	2.97	Antares
14	4.3105E+11	2.87
13	4.1537E+11	2.77
12	3.99075E+11	2.66
11	3.82085E+11	2.55
10	3.64304E+11	2.43
9	3.45609E+11	2.30
8	3.25843E+11	2.17
7	3.04798E+11	2.03	B3 V
6	2.82188E+11	1.88	B4 V
5	2.57602E+11	1.72	B5 V
4	2.30406E+11	1.54	B7 V
3	1.99537E+11	1.33	B9 V
2	1.62922E+11	1.09	A5 V
1.75	1.52399E+11	1.02	A8 V
1.5	1.41094E+11	0.94	F1 V
1.25	1.28801E+11	0.86	F7 V
1.1	1.20826E+11	0.81	G0 V
1	1.15203E+11	0.77	G2 V (Sol)
0.9	1.09291E+11	0.73	G7 V
0.8	1.03041E+11	0.69	K1 V
0.7	96385703793	0.64	K3 V
0.6	89235821902	0.59	K5 V
0.5	81460787656	0.54	K7 V
0.4	72860743480	0.49	K8 V
0.3	63099254792	0.42	M0 V
0.2	51520325797	0.34	M4 V
0.1	36430371740	0.24	M5 V
0.08	32584315062	0.22	M9 V

For Jupiter masses (Brown dwarfs, superjovians, and LGGs):

Jupiter	limit/metres	limit/AU
masses
70	29774421720	0.20	Largest BD
60	27565758087	0.18
50	25163979198	0.17
40	22507347229	0.15
30	19491934472	0.13
20	15915097852	0.11
10	11253673614	0.08	Smallest BD
5	7957548926	0.05
2	5032795840	0.03
1	3558724067	0.02	Jupiter

For Earth masses (SGGs, large terrestrials):

Earth	limit/metres	limit/AU
masses
100	1996577120	0.01331	Saturn
50	1411793221	0.00941
25	998288560.2	0.00666
15	773270993.7	0.00516	Uranus/Neptune
10	631373122.5	0.00421
9	598973136.1	0.00399
8	564717288.4	0.00376
7	528244653.4	0.00352
6	489059517.7	0.00326
5	446448216.4	0.00298
4	399315424.1	0.00266
3	345817301.4	0.00231
2	282358644.2	0.00188
1	199657712	0.00133	Earth

For Earth masses (small terrestrials):

Earth	limit/metres	limit/km
masses
0.8	178579286.5	178579	Venus
0.5	141179322.1	141179
0.4	126274624.5	126275
0.3	109357032.7	109357
0.2	89289643.27	89290
0.1	63137312.25	63137	Mars
0.05	44644821.64	44645	Mercury
0.01	19965771.2	19966	Moon

 

[Carlobrand]

Sooo ... the jump limit for Terra is now a bit under 16 diameters instead of 100? Do I have that right? Why deviate so far from canon?

What about the military implications? For a size-8 world, attacking fleets were jumping in roughly 1.3 million Km out; they had a 2 hour 20 minute jaunt in (1 and 50 if they came in at speed, planning to decelerate all the way in) and no intelligence on what was at the planet until they were already more than halfway there; if they didn't like what they saw, they had a hard boost to the jump limit if they planned to jump out - and a competent defender's got sensors in far orbit and will already be boosting to meet him by that time. Favors defense.

If I have this alternate range thing right, the attacker jumps in well within sensor and weapons range of the planet; he can plan a bit of extra space to take his look see while still outside of the jump-limit and can choose to jump out immediately if he doesn't like what he sees or start launching missiles immediately if he does.

Seems to me it would make life very unpleasant for anyone in orbit during wartime. The first clue they have that a raider's arrived is when the missiles start hitting.

 

[BytePro]

All my CT stuffs states '100 diameters of a world' for safety - not of any given object. Worlds (not including GGs - terrestrial seemed be generally implied) were all assumed to have generally the same density - that is what I'd extrapolate from. (Our sun is just over 1/4 as dense as Earth, IIRC).

Rule mechanics give 42% chance of misjump between 10 and 100 diameters - jumping (pun) to 97% within 10. Factor that in to indicate any formula should be non-linear.

Regardless, there was plenty of room for not using 100 diameters from a star in the same context as from a world... till someone took 100D to be universal.

Where did that first happen?

 

[far-trader]

Regardless, there was plenty of room for not using 100 diameters from a star in the same context as from a world... till someone took 100D to be universal.

Where did that first happen?

Pretty early on actually. At least for Gas Giants (though not stars, nor universally).

The Traveller Book (collected LBB1-3 plus stuff) copyright 1982 includes a Typical Travel Times table (page 54) with Typical Use for Distance section of "Safe jump distance from... " for all world sizes 1 through A and small and large gas giants. They look to be 100D for a small gas giant being Neptune to Uranus size and a large gas giant being about Saturn size. The listed "Safe jump distance from... " being rounded to 5 million km and 10 million km respectively.

There may be other sources but that's the one that leaps to mind.

 

[BytePro]

Don't have that one... but noticed Scouts (1983 15th printing edition) did have 20 to 200 radii for stars as higher probability of misjumps (see post in "jump masking" based on gravity ).

Scouts has small GGs as 40,000 to 120,000 km in diameter (gives 20 to 60 thousand for radius - pg48) - and Large GGs as 'at least' 120,000 km. So that would be 4 to 12 million km for small - and at least 12 million km for large.

So 5 million is quite on the low side for most of the range of small GGs - Neptune and Uranus are close though.

The 10 million for large GGs is quite low - being ~83% of the minimum for a large GG. (Jupiter, IIRC, would be over 14 million km for 100D and Saturn over 12 million).

 

[aramis]

200 Radii is 100 diameters.

 

[Otto Harkaman]

Well I didn't understand at all the original conversation of this thread that Tobias resurrected. But I have been thinking of safe or normal jump distances from planets for game playing Mayday or CT.

I noticed that chart Far-Trader mentioned.

I will probably use it to help construct some solar space battlefields for Mayday and maybe CT. Interesting I have a picture of the Efate solar system from one of the old computer games. I think according to this chart and Mayday's scale 300,000km that a ship only has to be two or three hexes away to jump? In Mayday it says a ship has to be at least forty hexes away from a world pg11.?

I don't know how they derived from the basic information on how to construct the solar system A646930-D. It would be easy to put the inner solar system on a hex map with the the jump safe zones marked. I think it would make interesting space combat.

 

[BytePro]

200 Radii is 100 diameters.

Yes - sorry that observation is so automatic for me I neglected to point it out even though I meant to...

My comment was in reference to that as a reference to 100D other than just for terrestrial 'worlds' (a question I earlier posed). Though not an absolutely explicit one given the phraseology used.

far-trader's table supports that ambiguity as well - as further evidenced by the scan of same that Otto provided above... 'a safe jump distance from large gas giant' of 10,000,000 km is less than 100D of the minimum diameter as defined in Book 6, which would be, at a minimum, 12,000,000 km (not sure if 1982 The Traveller Book provided a different Large GG diameter - or whether its contents are 'officially' considered superseded by later works).

Though I had my 'Jump Density Threshhold' (re: http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=26200 post #11) thought up as an armchair exercise - in play, simply used the 100D limit and ignored stars for jump (close in orbits not being interesting for play and most systems lacking larger stars, probably wouldn't have mattered), so really only used 100D for all worlds.

... I think according to this chart and Mayday's scale 300,000km that a ship only has to be two or three hexes away to jump? In Mayday it says a ship has to be at least forty hexes away from a world pg11.?

That scale sounds off - at 6G, 300,000 km is over an hour, IIRC.

Jump in terms of space combat basically halts space combat, so not sure that would be very enjoyable? (BTW: 100 D safe limit can be reduced over 10D for ~42% risk in CT.)

 

[aramis]

TTB provides no diameters for GG's by class at all, other than by the 100 diameter radius inferring a size for the GG's. It does give explicit template sizes for Jupiter, Saturn, Uranus and Neptune in ship combat.

 

[BytePro]

Thanks - much appreciated!

I guess I should have asked earlier - any CT 100D jump limits mentioned for stars, and, shudder, that other jump issue?

Canon, or not, doesn't matter to me... my resources* and knowledge being limited in that area, and my speculations are just that (do know many of these topics are hotbeads for strong sentiments to derail, er, civil discussions - hoping to avoid that level, of course). My curiosity does have an impact on stuff I hope to freely share that others might find useful (mostly not wanting to blatantly trample on what's already published, and defacto accepted, out of my ignorance).

* - I've intentionally avoided buying current collections for a number of reasons (though eventually I know I'll break down...)

 

[Carlobrand]

"That other jump issue"? There's another jump issue?? Oh, lord.

 

[far-trader]

...and, shudder, that other jump issue?

"That other jump issue"? There's another jump issue?? Oh, lord.

Only ONE other jump issue?

That's a relief