Setting Up A Relay Network Around Duna

[The Flying Kerbal]

I'm thinking about setting up a satellite network around Duna; I realise geostationary networks aren't possible as Ike gets in the way, but that's not what has me scratching my head.  No, it's more like a Catch 22 situation I'm thinking about.

How can I control the deploying of my satellites if I don't have a relay network to pass signals from Kerbin to Duna???  I'm pretty sure this has an obvious and simple solution - and I admit I haven't really thought about it very much just yet - but on the face of it, it does seem to be a problem.

Advice, suggestions any and all help will be very much appreciated.

Thanks.

[Human Person]

6 minutes ago, The Flying Kerbal said:

How can I control the deploying of my satellites if I don't have a relay network to pass signals from Kerbin to Duna???

you need a direct connection with the first satelite.

[Aegolius13]

Well, the satellites are your relay network.  They will work fine by themselves as long as there is nothing (most likely, Duna or Ike) blocking line-of-sight between the satellite and Kerbin.  You should be able to time your manuevers to fine-tune your orbits for when this path is clear.  Also, if you're playing on standard settings, you can get limited probe control even without signal.  This should work for basic stuff like pro/retrograde burns, though you will probably need a connection to get your orbits exactly how you want.  

Word to the wise - when setting up satellites around Duna, be careful not to let them cross into Ike's SOI, or they'll get flung all over the place.  They can either by close to Duna, or way far out past Ike, but watch out for that middle range.  

[Spricigo]

How you planned your network around Duna? How you planned to delivery the relays? 

Depending on your setup it may be just a matter of not doing the capture behind Duna*.

Assuming you send the vessel in a Hohmann transfer you want your capture on the day side of Duna.

... Or you just bring more fuel so you can do the maneuver even if you lost LoS at the ideal time.

...Or bring an extra relay for then sole purpose of bouncing the signal for the capture burn.

 

Many ways yo solve the issue.

 

 

I sometimes have a Remote Control Point. But that is because it's  "some extra" to build into a different vessel.

*ok, something else may get in the way, but a lot less likely.

[The Flying Kerbal]

Great answers guys, thanks so very much! 

[Draalo]

I recommend 2 relays in a excentric polar orbit.

 

Aim for the center of una when you do the transfer burn. When entering Dunas SOI just do a small burn so your PE is 60km above north or southpole. At PE just burn untill you keep in orbit. 

Decouple sat1, just a probecore with solar and a relayantenna. No need for engines.

Sat2 will be the same but still with attached tank and engine.

At AP you may change inclination, raise your PE as high as your remaining dV budget allows, at PE lower the AP as much as possible.

 

At least one sat will allways have line of sight to Kerbin.

 

[The Flying Kerbal]

Great answer Draalo, I was toying with this idea myself but wasn't sure if it was a good one, your answer has now convinced me that this is the way to go!

[bjerrang]

Edited January 23, 2018 by bjerrang

[Snark]

Also, note that if you've got a rover exploring the Ike-facing side of Duna... Ike orbit is a great place to put a Duna-synchronous satellite.    Just go for a high polar orbit around Ike.

[Gordon Fecyk]

If you can match Ike's orbit precisely, you can place relays along the orbit. I time-warped this for a couple of years and found it stable enough to work.

You don't need to do this though, since relay antennas don't need to point in a specific direction. Simpler to have this trio of relays inside or outside Ike's orbit.

If you're curious though, get a relay launcher of some kind in low Duna orbit, target Ike and match its inclination, then study Ike's path for a bit. Find its AP and PE in map view. As you place each relay, use the target markers to find the right spot for each one. I'm not exactly sure because Ike's orbit isn't a perfect circle, but maybe if the speed in Target mode is zero when Ike is targeted, it should be set.