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PostPosted: Tue Apr 04, 2017 7:04 pm 
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Posts: 314
Location: Near Frankfurt, Germany
Besides the star system generation rules, I´m also working on my own setting.

I like my sectors relatively sparse, more like much of the Gateway Domain than like the Spinward Marches, but with Traveller jump drive, this results in four problems:
1) Jump-1 pretty much gets you nowhere
2) Jump-2 travel options are severely constrained
3) Jump-3 drives and higher are pretty technologically advanced, shutting less advanced actors out from interstellar travel unless they get their drives from elsewhere
4) Fuel requirements at higher jump numbers cut harshly into the available cargo space of a vessel, making trade in particular far less efficient

The fourth point is mitigated with the optional rules to halve jump fuel consumption, but the other problems remain.

The solution I came up with for my setting is this:
- Jumping is possible only between stars that are sufficiently close and sufficiently massive that a jump lane has formed between them.
- To determine presence of a jump lane between two stars, add the Lane Radius of each star; if the result is equal to or higher than the distance in hexes/parsec between the two stars, a jump lane exists
- Lane Radius is 0 for brown dwarves, 1 for M-class stars, 2 for D, F, G and K-class stars and 3 for O, B and A-class stars.
- Jump duration is 48 hours, plus (120 divided by jump drive rating) hours per parsec jumped, or 48+1d6 hours for jumps within a system.
- Jump fuel consumption is 5% of the ship´s mass (in d-tons) per parsec jumped, or a flat 5% for jumps within a system.

This means maximum jump distance is, in practice (with O/B/A stars so rare), between 2 and 4 parsec. At a 15% probability for a star system per hex, my default setting, this gives a nice "landscape" of clusters, arms, dead ends and rifts.
Travel times are (at Jump-1/Jump-2/Jump-3)
1 parsec: 7 days / 4 days, 12 hours / 3 days, 16 hours
2 parsec: 12 days / 7 days / 5 days, 8 hours
3 parsec: 17 days / 9 days, 12 hours / 7 days
4 parsec: 22 days / 12 days / 8 days, 16 hours

Regardless of jump ratings, starships would probably be constructed with 20% (4 parsec´s worth) jump fuel and 4 weeks (perhaps 6 for Jump-1 ships) of reactor fuel.

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Space isn't remote at all. It's only an hour's drive away if your car could go straight upwards. Sir Frederick Hoyle
Earth is the cradle of humanity, but one cannot live in a cradle forever. Konstantin Tsiolkovsky
Man has earned the right to hold this planet against all comers, by virtue of occasionally producing someone completely bat**** insane. xkcd #556
Just like people, stars can be very important without being terribly bright. Phil Plait, "Bad Astronomy"


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PostPosted: Tue Apr 04, 2017 7:17 pm 
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Location: Near Frankfurt, Germany
Here´s the map I´ve made for the setting; it´s 3x3 sectors, the entire extent of the setting that is known at the time, with the Sol system at hex 1620 of the central sector.

I´ve populated the map with stars as soon as I nailed that part of the generation rules down, but no planets so far. At 15% probability per hex, there´s approximately 1,700 systems and, with binaries and trinaries, maybe 2,500 stars.

Unfortunately, the map is zoomed too far out to show the actual stars; what this shows is a network of jump lanes - not ALL lanes, but those necessary to connect all F, G and K class stars (i.e. those most likely to have habitable worlds) to one another, excluding of course those too isolated to connect to any other (maybe a few dozen overall). The network includes other stars, but only those necessary to connect F, G and K class stars to one another - stop-overs on the trip from one important system to another.
Once full systems are generated, I expect to change the network into one connecting all systems with habitable worlds with one another instead of by star type; since most of these habitable worlds should be in the same kind of stars, I don´t expect the overall network to change much, though.


Attachments:
Star Map.jpg
Star Map.jpg [ 192.1 KiB | Viewed 389 times ]

_________________
Space isn't remote at all. It's only an hour's drive away if your car could go straight upwards. Sir Frederick Hoyle
Earth is the cradle of humanity, but one cannot live in a cradle forever. Konstantin Tsiolkovsky
Man has earned the right to hold this planet against all comers, by virtue of occasionally producing someone completely bat**** insane. xkcd #556
Just like people, stars can be very important without being terribly bright. Phil Plait, "Bad Astronomy"
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PostPosted: Wed Apr 05, 2017 12:14 pm 
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Joined: Tue Mar 24, 2009 12:44 pm
Posts: 5
I'm surprised there aren't any disconnected lane segments. Is there any alternate FTL system that might allow a transit without a jump lane meeting the described threshold?

Simon Hibbs

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PostPosted: Wed Apr 05, 2017 1:17 pm 
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Joined: Thu Jul 12, 2012 10:11 pm
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Location: Near Frankfurt, Germany
shibbs wrote:
I'm surprised there aren't any disconnected lane segments. Is there any alternate FTL system that might allow a transit without a jump lane meeting the described threshold?

Simon Hibbs


There actually quite a few stars that are too isolated to connect to the lane network, maybe a hundred or so; I haven´t included any lanes between them because they´re not part of the network. You can assume isolated single systems and small cluster of up to five systems to sit in all of the larger gaps in the map.

There´ll also be many M class stars near those connected by the lane network that don´t have any lanes shown here because, for this preliminary network, I assumed they wouldn´t hold any inhabited worlds - so for this network, they are only included if a stopover there is necessary to get from one F/G/K star to another.

Both decisions are to reduce clutter on the map and make the more relevant features easier to notice.


As for alternate FTL systems, the setting is at TL 12 at the moment; I imagine in the setting´s future a more advanced jump drive may be developed that extends jump lane thresholds by another parsec. I haven´t done a complete check, but that should be enough to connect every star on the map; but it would also virtually eliminate all those rifts, as right now, a lot of what looks like a wide rift on the above map is actually full of 3 parsec gaps between M class stars.
Or maybe an alien civilization from outside the maps area already has such a jump drive, and uses it to go where nobody else can?

_________________
Space isn't remote at all. It's only an hour's drive away if your car could go straight upwards. Sir Frederick Hoyle
Earth is the cradle of humanity, but one cannot live in a cradle forever. Konstantin Tsiolkovsky
Man has earned the right to hold this planet against all comers, by virtue of occasionally producing someone completely bat**** insane. xkcd #556
Just like people, stars can be very important without being terribly bright. Phil Plait, "Bad Astronomy"


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PostPosted: Wed Apr 05, 2017 6:02 pm 
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Joined: Thu Aug 28, 2008 10:09 am
Posts: 501
I suppose I'm just thinking that it might be nice to distinguish ships by their range or ability to do 'off grid' jumps, but then you pretty much might as well use regular Jump Dives.

Simon Hibbs

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Check out StarBase, the open source science fiction campaign mapping application.


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PostPosted: Wed Apr 05, 2017 9:40 pm 
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Location: the Retirement Coast, NSW, Australia
What are D-class stars? White dwarfs? Aren't they small, low-mass, and dim?

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PostPosted: Thu Apr 06, 2017 7:35 am 
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Joined: Thu Jul 12, 2012 10:11 pm
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Location: Near Frankfurt, Germany
Agemegos wrote:
What are D-class stars? White dwarfs? Aren't they small, low-mass, and dim?


Yup, white dwarfs. Small and dim doesn´t matter for the purpose of jump lane length; their mass varies, but most seem to be around the same mass as K class main sequence stars.

_________________
Space isn't remote at all. It's only an hour's drive away if your car could go straight upwards. Sir Frederick Hoyle
Earth is the cradle of humanity, but one cannot live in a cradle forever. Konstantin Tsiolkovsky
Man has earned the right to hold this planet against all comers, by virtue of occasionally producing someone completely bat**** insane. xkcd #556
Just like people, stars can be very important without being terribly bright. Phil Plait, "Bad Astronomy"


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PostPosted: Mon Aug 28, 2017 2:02 pm 
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Joined: Tue Jul 08, 2008 8:42 pm
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Location: Texas, USA
I really like this idea. I have been fooling around with an idea of a setting similar to Lois McMaster-Bujold's Vorkosigan setting - Jump points and Jump lanes that don't seem to regard distance, but have been struggling to figure out how to MAP this and more importantly, how to create a random setting.

Using your ideas might just work... :)

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PostPosted: Mon Aug 28, 2017 2:05 pm 
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Location: Texas, USA
One idea I came up with for Jump Fuel issues it to reduce the fuel required with TL.

Code:
TL  % Fuel
9     10
10    8
11    5
12    4
13    3 
14    2
15    1

That makes a higher TL J-1 drive actuall worth something, as it uses less fuel.

Just a thought.

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My friends call me Richard. You can call me Sir.
www.XmasDragon.com


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PostPosted: Mon Aug 28, 2017 2:40 pm 
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Joined: Sat Sep 01, 2012 2:44 pm
Posts: 183
Location: Colorado
Cyborg IM1 wrote:
One idea I came up with for Jump Fuel issues it to reduce the fuel required with TL.

Code:
TL  % Fuel
9     10
10    8
11    5
12    4
13    3 
14    2
15    1

That makes a higher TL J-1 drive actuall worth something, as it uses less fuel.

Just a thought.


That's a pretty big difference! Will make a huge difference to ship designs and the economy of trade. How widespread would the higher TL ships/shipyards be?

On a slightly related note, has anyone tried limiting jump/ship displacement by TL? Something like this:
Attachment:
Screen Shot 2017-08-28 at 8.42.13 AM.png
Screen Shot 2017-08-28 at 8.42.13 AM.png [ 14.65 KiB | Viewed 163 times ]

The displacements are arbitrary, just placeholders to illustrate the idea. (Perhaps this needs a thread of it's own, apologies for the thread jack).


Last edited by hiro on Mon Aug 28, 2017 2:44 pm, edited 1 time in total.

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