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Jool Relay Network


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So, I wanted to build a Relay Network for a Jool mission. So I sent several satellites there. The problem is that the satellites are not communicating with each other, making the network impossible. Any idea what could be happening?

oh, BTW. I’m using a single core, the HECS2 for the satellites, as well as a single Communotron 88-88 antenna.

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You need a relay antenna to communicate between different vessels, a direct antenna like the 88-88 can only send data to another antenna or the tracking stations on Kerbin. You’ll probably want the RA-100 dish as it’s the most powerful relay, however relay dishes are big and heavy compared to a direct antenna of the same power,

For Jool, as for any planet, the best orbit for relays is a high polar orbit: with three or four evenly-spaced relays you’ll have coverage almost all the time without the inconvenience of Jool or a moon getting in the way and blocking the signal, or one of the moons snagging your satellite and lobbing it out of the solar system with a gravity assist (glowers at Tylo); the same applies for relays around the moons, though I’d stick to just Laythe unless you plan to do a lot on one of the other moons.

Three high-orbit, evenly-spaced relay sats with RA-15 dishes should cover any moon with enough signal strength to reach anywhere on the ground and also reach the high Jool orbit relays with an RA-100 or two which can then forward the signal back to Kerbin.

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5 hours ago, VoidSquid said:

In addition to that, here's a good guide to build a relay network for the whole Kerbol system:

https://wiki.kerbalspaceprogram.com/wiki/Tutorial:Setting_up_a_CommNet_system

I follow similar models, and that I do them bit by bit.

So basically as a decent window opens on a planet I send a small fleet a ships, headed by the relay network sats.

(Kerbin, Mün and Minmus gets theirs as soon as the tech is available).

 

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15 minutes ago, Curveball Anders said:

I send a small fleet a ships

Old me is just (again) procrastinating.  Seven rockets with relay sats (three each) on the way to the Jool system, plus five ScanSat rockets (four sats each) ... plus rovers, landers, tankers, taxis.

I'm accepting another Mun landing contract now.

I'm lazy :D  

Edited by VoidSquid
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1 hour ago, jimmymcgoochie said:

 

For Jool, as for any planet, the best orbit for relays is a high polar orbit: with three or four evenly-spaced relays you’ll have coverage almost all the time without the inconvenience of Jool or a moon getting in the way and blocking the signal, or one of the moons snagging your satellite and lobbing it out of the solar system with a gravity assist (glowers at Tylo); the same applies for relays around the moons, though I’d stick to just Laythe unless you plan to do a lot on one of the other moons.

 

I would offer the alternate opinion that as a "minimal" relay constellation network, the best inclination would be equatorial. The reason being, that most of your "work" is probably going to be on or around equatorial anyway - shooting for moons, etc. 

Note, a 3-satellite constellation cannot give 100% coverage (and if its equatorial, the patches of no comms will be near the poles) but it can come pretty close, and if you have the available readout on inclination and take care to set all sats to 0.0deg, then the "dropout" will be at latitudes >89.9deg.

The ideal layout is an equilateral triangle around the body:

KSP%20CCD%20Image%20115.png

The minimum altitude for each satellite to "see" each other, assuming a perfect equilateral triangle, is 2x radius of the body (but in practice, you'll want a bit more to ensure comms even if imperfect). For Jool, this is 2x 6000km. Laythe's orbit is 27000km and its SOI is 3700km so choose the altitude of the satellites between 12,000km - 23,300km and they won't be peturbed by Laythe.

Jool's Ap is 72Gm and Kerbin's is 14Gm so the worst case distance could be (I've not worried about if they're in orbital resonance which might make it never occur...) 86Gm. Thus, RA100 is required. 1 of the relays could be a small one. You couldn't rely on only 1x RA100 because it will be occluded by Jool; but at any point, only one/none of the sats will be occluded.

Don't forget that at certain times Jool->Kerbin direct path will be blocked by the sun; so for 100% comms you'd need something else, somewhere else. Eg a relay network around another planet or on its own solar orbit. In my first career when I did the sentinel contracts I always stuck a relay on it too, as a "nice to have".

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I totally forgot about occlusion modifier. The point being, 3 isn't perfect but will 99.9% do the job. The layout for an "ideal" 4 satellite constellation is possible but its a bit complex to visualise.

When I last sent a bunch of relay satellites up I managed to design a very compact (vertical) package so it was possible to stack 6 without flyability issues of a taller payload.

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