Orbiting planets?

jedion357's picture
jedion357
December 15, 2010 - 1:43pm
KH's rules says a ship in orbit has a speed of 0 but moves 1 hex per turn
A KH's turn is 10 minutes

this means a ship orbits a planet 1/ hour

is that realistic?

should a space station be wizzing around a planet that fast too?

how should we portray a moon orbiting a planet?

Jedion's mind wants to know.
I might not be a dralasite, vrusk or yazirian but I do play one in Star Frontiers!
Comments:

Anonymous's picture
w00t (not verified)
December 15, 2010 - 1:56pm
Orbital Speed

The international space station travels around 27,000km/hr and completes about 15 order in a day.
ISS Tracker

I do not have a game mechanic at this time but interested in making one. Would fit with my categorical orbial listing in the last article. I'm still working on HEO yazarian drop speeds. lol

TerlObar's picture
TerlObar
December 15, 2010 - 2:23pm
It's a little fast but not terribly so and for the purposes of the game it works just fine.

In Low Earth Orbit (LEO), at say an altitude of 600km or about 7000km from the center of the planet, the orbital speed is about one orbit every 100 minutes or ten turns.  At a distance of 10000km from the center of the planet (i.e. center to center of two hexes), the orbital period would be about 2.8 hours or 16.5 turns.  So you could argue that it should really be only half a hex per turn but that's a little unwieldy.

Anything would orbit at that speed, ship, station, stray boot.  It depends on how close the moon is to the planet.  If it is just outside the atmosphere, it should be moving that fast.  If it is far away, then it should be moving very, very slowly.  The Earth's moon on the KH map would be 39 hexes away and, moving at it's orbital speed of 1 km/s, would take 16.66 turns to move one hex.
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Anonymous's picture
w00t (not verified)
December 15, 2010 - 2:48pm
So... let's make some chits with printed speed ratings. Just keep track of the turns and vola, you know when to move chits!

lol.

I love it, neither of us helped with a game mechanic. :-)

jedion357's picture
jedion357
December 15, 2010 - 2:56pm
Honestly though a moon wont move in the course of a KH's encounter; 16 turns? game wont go that long unless you have 20 ships using advanced damage rules.

for things in 1 hex orbit I guess we could allow them to move every other turn or every 3 turns to simulate slower speeds or we could put them 2 hexes away and allow them to move in an orbital path 1/turn.
I might not be a dralasite, vrusk or yazirian but I do play one in Star Frontiers!

TerlObar's picture
TerlObar
December 15, 2010 - 4:35pm
But if they were two hexes away they would move even slower.  At 20,000 km from the planet center, the orbital period would be 47 turns (to cover 12 hexes) so one hex every 4 turns Smile.

And yes, effectively the moons wouldn't move very far at all during a KH scenario and could be considered stationary.
Ad Astra Per Ardua!
Webmaster - The Star Frontiers Network & this site
Founding Editor - The Frontier Explorer Magazine
Managing Editor - The Star Frontiersman Magazine

jedion357's picture
jedion357
December 15, 2010 - 5:39pm
TerlObar wrote:
But if they were two hexes away they would move even slower.  At 20,000 km from the planet center, the orbital period would be 47 turns (to cover 12 hexes) so one hex every 4 turns Smile.

And yes, effectively the moons wouldn't move very far at all during a KH scenario and could be considered stationary.


thats cool. how far (in hexes) could a station realistically orbit a planet

For myself I'd make a transparency of the hex for a planet with orbit lines in hex patterns surrounding that hex
each orbit line would have the appropriate numbers on it for simulating an orbit ie: "1 for 4" would be printed one the 2 hex away orbit line thus I could secure this transparency over the hex map where I want the planet (my KH's map is laminated so I'd scotch tape the tranparency to it)

perhaps a chart of orbital hex distance from the planet and the speed of that orbit might find its way into the zine- that'd be a great reference table.Wink
I might not be a dralasite, vrusk or yazirian but I do play one in Star Frontiers!

dmoffett's picture
dmoffett
December 18, 2010 - 5:42pm
Does not the mass of the planet or other stellar body have an effect on this?
The bombing starts in five minutes.

TerlObar's picture
TerlObar
December 19, 2010 - 3:22pm
dmoffett wrote:
Does not the mass of the planet or other stellar body have an effect on this?

Yes, but in the case of a station, ship or small moon, not significantly.

The earth's moon is much larger that most moons relative to the size of their parent planet and the earth and moon actually rotate about a point about 1000 km below the surface of the Earth, not the Earth's center but that is on a period of ~28 days so not something you would even worry about in a game scenario.
Ad Astra Per Ardua!
Webmaster - The Star Frontiers Network & this site
Founding Editor - The Frontier Explorer Magazine
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dmoffett's picture
dmoffett
December 28, 2010 - 11:43am
"That's no moon... Its a space station!"
The bombing starts in five minutes.