Position probe in orbit of planet 170* off?

[xtoro]

So I have outer planets installed. I'd like to use Jool's orbit as a relay network using RemoteTech. One probe will orbit Jool on a polar orbit, and I want the other to be on the same orbital path as Jool, but 170 degrees off, almost directly opposite from it, behind the sun. The reason I want it 170 degrees and not 180 is so that the sun doesn't block the signal between the 2 probes.

What's the best way of doing this while using as little dV as possible?

Option A) Launch ~180* off of the normal launch window, but use lots of dV to raise the PE when I get to the AP.

Option Launch to Jool, capture, then leave Jool SOI to have similar orbit. Then lower PE or raise AP to get a different orbital period, and wait years for them to be opposite from each other.

Option C?) Is there maybe some gravity assist that might help land me close to where I want to be?

[CalculusWarrior]

Option A will be the fastest one, but yes as you noted, it will use quite a bit of delta-v (as it's essentially a Hohmann Transfer in solar orbit). B will take as much delta-v as a Jool transfer (plus the amount spent maneuvering), but will take many, many years to work. As for C, I'm not an expert on gravity assists; it may be possible to use Jool to edit your orbit so that it's close to what you want, but that will likely take a long time as well.

Thus, in my opinion, Option B is your best shot.

[Snark]

You might save some dV with option B, but it seems like a lot of hassle-- most of the dV in going to Jool is with Kerbin departure, not Jool arrival. I'd go with option A. It's just a relay satellite, right? Not like it's going to be a monster huge craft, the only heavy components will be a couple of 0.5 ton antennas and a gaggle of RTGs.

In principle, you could save a little dV by getting a gravity assist off Duna, but the amount would likely be so small that it's really not worth the bother.

A suggestion, when launching your anti-Jool relay, give it some solar inclination so that its orbit is "tilted" from the plane of Jool's orbit. Doesn't have to be a lot, just a couple of degrees. That will be enough that you don't have to worry about the sun blocking the signal-- the sun is pretty tiny when seen from Jool's distance.

[FancyMouse]

I wouldn't bother to actually place the satellites in Jool SoI. For relay all it matters is the orbital altitude, not its exact location in that orbit. So if I were you I would just do identical Hohmann transfers (relative to Sun) with two satellites launched 170/360 Kerbin year apart.

[xtoro]

But the reason I went with 170 degrees is so that the sun will never be between them. If I place it 180 across and inclined, wont there still be 2 points where the sun is between them at the ascending and descending nodes?

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I wouldn't bother to actually place the satellites in Jool SoI. For relay all it matters is the orbital altitude, not its exact location in that orbit. So if I were you I would just do identical Hohmann transfers (relative to Sun) with two satellites launched 170/360 Kerbin year apart.

I thought of this as well, but it's as much dV as option A. The reason I want Jool to have one is because of probes and rovers in the Jool system of moons.

[FancyMouse]

I thought of this as well, but it's as much dV as option A. The reason I want Jool to have one is because of probes and rovers in the Jool system of moons.

You need another network for within Jool system anyway. I wouldn't overlap the responsibility for communication within Jool system and interplanetary relay, as it will simplify the design, at least to me. e.g. if I don't put the relay satellite around Jool I don't need to worry about blackout time by Jool etc.

dV is not important actually - just spam Ions. Using this approach you don't care your orbit shape, as long as period matches Jool's.