Help with a relay attempt.

[MickB]

In my Galileo install I'm testing out designs for an unmanned lander probe to Gratian. Since Gratian has an atmosphere I can't keep a Communotron 88-88 opened as I enter the atmosphere. So what I'm trying to do is have a short range Communotron 16-S on the lander that won't get ripped off by the atmosphere, and have a probe orbiting above with an 88-88 connected back to command to relay a signal to the lander. I also have an RA-2 relay antenna on the orbiting probe. When I cheat everything into Gratian's orbit the orbiting probe part functions fine, has a good connection, but when I decouple the lander part it gets no connection to the relay, even when they're right next to each other. 

 

In short: 

Lander: has Communotron 16-S

Probe relay: has Communotron 88-88 and RA-2 relay antenna

Lander won't connect to probe's signal. 

Everything has power, line of sight, probe cores...what am I doing wrong?

[Gordon Fecyk]

If this is anything like trying to land a probe on Eve, which would be hasher plasma-wise, you're likely going to lose comms at some point during the descent and then regain it after the worst of the re-entry process.

It almost sounds like the lander is missing a probe body of its own.

Can you make craft files available for inspection?

[MickB]

https://pastebin.com/4vTaxtGR

I think the only two mods for parts are B9 and Interstellar Extended. I can make another one with all stock parts if that helps.

Also, as I keep playing around with this, if I just have the largest relay and nothing else on the orbiting probe, it works. Can I not use a direct antenna for connection to KSC and then a smaller relay on the same probe to relay the signal? Or do I need a relay that can connect to KSC?

[Gordon Fecyk]

OK I grabbed the needed mods, and holy cow there's a lot of them. Here's a screen shot:

That red arrow is the Communotron 16-S. Just to save my head from spinning I'll make a stock version of this:

I'll use Rapiers in place of your nuclear atmospheric engine, and try to land this on Laythe in the stock game. At first glance, I'll need a local relay network around Jool and probably a 'regular' geostationary relay network around Kerbin to ensure connectivity.

[some time later]

I seem to have connectivity at least to here. And I managed to take this craft through Laythe's atmosphere without signal loss. Odd; at first I had plasma blackout turned off, but then I turned it on and tried again, and didn't lose signal through the entire descent.

And then Ferram Aerospace laughed at the un-aerodynamic design and the thing broke apart in the thicker air. :-) But hey, it should work. On the second attempt I managed to get to 3000 m on a slow descent in air-breathing mode, and still haven't lost signal. I'm not sure why your original design is failing.

Edited July 1, 2017 by Gordon Fecyk
Added progress on Stock example

[Gordon Fecyk]

8 hours ago, MickB said:

Can I not use a direct antenna for connection to KSC and then a smaller relay on the same probe to relay the signal? Or do I need a relay that can connect to KSC?

If you want to control this from the Space Center directly, the probe needs to see a relay probe that can see the Space Center somehow. If there were a crew on that service craft and the number of pilots required was met, you could control probes from that crewed service craft without that craft needing a KSC connection. However, the crewed craft still needs a relay antenna to do so. 

[MickB]

19 hours ago, Gordon Fecyk said:

If you want to control this from the Space Center directly, the probe needs to see a relay probe that can see the Space Center somehow. If there were a crew on that service craft and the number of pilots required was met, you could control probes from that crewed service craft without that craft needing a KSC connection. However, the crewed craft still needs a relay antenna to do so. 

Thanks, this is what I was hoping wasn't the case. Those big relays are hard to fit inside reasonably sized fairings without looking ridiculous. Thanks for the help and working the rest out. Good to know it'll work.

[Gordon Fecyk]

3 hours ago, MickB said:

Those big relays are hard to fit inside reasonably sized fairings without looking ridiculous.

If it helps, the fairings in 1.2 and later have optional scaffolding. I found I could fit three relay probes using RA-100s into a 3.75 m fairing and then use a 3.75 m craft to take it anywhere. Here's an example that you can easily replicate, or improve on.

These probes have Gigantor solar arrays, making them suitable for use around Jool just below Laythe's orbit. All you'd have to do to this craft is attach an additional probe core to control the empty scaffolding after deploying these guys, build the fairing, then use an appropriate launcher to get this package where you need it. Or just make sure you deploy that top probe last, so you can take advantage of its solar arrays and signal strength to control the launcher until you don't need it anymore.

While these RA-100s will certainly maintain a connection to Kerbin from as far as Jool, it's only at 55% strength and you'll need additional relays for some of the worlds in Galileo's Planet Pack. You should also mount a couple of 'regular' antennas to your launcher so you can control the empty scaffolding. Or just delete it via the Tracking Station, I suppose. Some additional tips: Set the force percent on those decouplers to zero, disable staging on them, maybe even disable staging on the fairing.