Multi-Satellite Launches

[spacegeek37]

I'm used to the direct communication system, but when I got the Breaking Ground expansion I tried to make some deep-space relays for rovers, and instantly ran into some problems.

 

Relay antennas are exclusively non-foldable, so has anyone come up with a way to fit more than one relay satellite onto a rocket without using huge parts? Making three trips per body seems like a complete waste of time and resources when these satellites weight so little. If not, is there a mod or config option to make folding antennas work as relays? I can't see why they wouldn't be able to.

[Geonovast]

The HG-5 is a folding relay antenna, it's just not very strong.

The best way to get multiple sats in one launch is to use the "Interstage Nodes" option on the fairings, which will let you attach multiple stacked payloads without them touching.

(not my pic)

[Superfluous J]

I basically do what @Geonovast posted. In fact I thought it was one of my pics One trick, mount the two interior satellites facing each other and you save the need for that inner truss, as the middle satellite will be attached to the same truss the top satellite is on, only on the bottom of it. Doesn't save mass, but it does allow for SLIGHTLY longer satellites. You can also slightly rotate the two bottom satellites so they are more "next to" each other than facing off. I think I have a pic around here somewhere I'll try to dig it up and update this post with it.

You can also - if you don't want to use fairings and don't mind a draggy front-end on your rocket (hint: you should mind a draggy front-end on your rocket) you can also radially mount the satellites. Back before they made a real atmosphere I frequently sent up 5 satellites at a time, 4 radially and 1 on the front.

Edited August 28, 2019 by 5thHorseman

[Aegolius13]

I like to stack multiple satellites per level, as shown below (those are smaller sats of course, but the same concept applies). You can do the same on upper levels using cubic octagonal struts to create extra nodes).  But I find it makes sense to put fewer sats on the top, so the fairing can taper around them.

 

 

 

[spacegeek37]

18 hours ago, Geonovast said:

The HG-5 is a folding relay antenna, it's just not very strong.

The best way to get multiple sats in one launch is to use the "Interstage Nodes" option on the fairings, which will let you attach multiple stacked payloads without them touching.

Thanks for that. I somehow missed interstage nodes since they were added ages ago, and haven't seen them in any videos that I can remember. You just made my KSP save a whole lot cooler.

[Cavscout74]

I also tend to make a network with RA-2 relays around a planet then a single larger relay in a highly elliptical polar orbit - so rovers or whatever talk to the nearest small relay, which bounces through the large relay back to Kerbin, rather than trying to make a network of RA-15 or RA100 relays in a single launch.   Especially early on, the large relay will get sent as a science probe that can also act as a relay, then later in the career the smaller relay network will get set up.

Edited August 28, 2019 by Cavscout74

[ajburges]

On 8/28/2019 at 3:51 PM, Cavscout74 said:

I also tend to make a network with RA-2 relays around a planet then a single larger relay in a highly elliptical polar orbit - so rovers or whatever talk to the nearest small relay, which bounces through the large relay back to Kerbin, rather than trying to make a network of RA-15 or RA100 relays in a single launch.   Especially early on, the large relay will get sent as a science probe that can also act as a relay, then later in the career the smaller relay network will get set up.

Another thing to consider is polar relays are great for many things:

> Resource scanner

> Anomaly detection over several days (at sufficiently high altitude you can see the entire planet face in Kerb net).

> With proper resonance, you are in a mapping orbit and can complete grab/temp scans above x contacts without fuel burn. Not to mention transmitting grav scans for every biome!

> I like to use my polar relay as a synchronization timer in case my Draim constellation desynchronizatizes.

Edited August 30, 2019 by ajburges

[vossiewulf]

These are landers, but it works just as well with satellites. I have bi-coupler and tri-coupler versions also. Can't remember if those or stock or not.

Relay sat. About 3000g orbiting outside Minmus. Solves a lot of problems. You only really need one, back it up with a few smaller much lower-power relay sats in close orbit around Kerbin to ensure global coverage. And for total coverage do triple relay sat launches for the Mun and Minmus.

[dire]

On 8/30/2019 at 3:57 PM, vossiewulf said:

These are landers, but it works just as well with satellites. I have bi-coupler and tri-coupler versions also. Can't remember if those or stock or not.

Relay sat. About 3000g orbiting outside Minmus. Solves a lot of problems. You only really need one, back it up with a few smaller much lower-power relay sats in close orbit around Kerbin to ensure global coverage. And for total coverage do triple relay sat launches for the Mun and Minmus.

Really like the design of your quad-probe. It looks more or less stock to me, although on close inspection it has some fiddly bits I can't quite identify. I thought the gold bit was a probe core, but it's the wrong shape. Although I am checking in version 1.5, so they might have new skins in later versions.

Your second probe might have some visual mods, or maybe some custom dish parts because I don't see a stock dish that looks exactly like those dishes do Ditto your forward solar panels; they either look like custom textures for the 3x2 stock panel, or custom parts. The large solar panels sort of look like Gigantor arrays maybe on pipes or actuators?

Anyway, worth mentioning is that this is a very inefficient way to do a relay satellite. Each additional dish adds less power than previous dishes, so if those are all RA-2 dishes for example with a range of 2 GM each, you could replace all of them with one RA-15 relay antenna with a range of 15 gm and probably wind up with a very comparable probe that has 1/10th the payload mass. My rule of thumb is generally, one dish is good, two is better, if I have to do more than 4 I might want to look at sending up two probes instead. Also one RA-2 can reach anywhere in kerbin's SOI that it has line of sight to, at least out to Minmus orbit. So unless you are talking to Dres that is probably overkill, and depending on what dish those are they might not reach out to Jool.

When I first looked at it I initially thought that was actually a carrier for like 6 individual relay sats, and that would be very cool. 

Edited September 2, 2019 by dire

[vossiewulf]

3 hours ago, dire said:

Really like the design of your quad-probe. It looks more or less stock to me, although on close inspection it has some fiddly bits I can't quite identify. I thought the gold bit was a probe core, but it's the wrong shape.

Yeah, I like parts, so I have most of them. The gold parts are Procedural Parts batteries. The pod is a little tiny 1-kerbal unit that is perfect for small landers from one of the Umbra Space Industries mods. The heat shields are SSTU.

The second one uses Coatl Aerospace antennas (he has lots of useful antennas) and a bunch of Near Future parts, Solar/Electrical/Construction, and I think some Contares parts too. I use stock parts pretty rarely.

3 hours ago, dire said:

Anyway, worth mentioning is that this is a very inefficient way to do a relay satellite. Each additional dish adds less power than previous dishes, so if those are all RA-2 dishes for example with a range of 2 GM each

They are 100G, but noted, thanks. Actually I never have figured out a way to tell exactly how many Gs are had by a relay sat with multiple antennas.

3 hours ago, dire said:

When I first looked at it I initially thought that was actually a carrier for like 6 individual relay sats, and that would be very cool. 

I did a six-lander Mun invasion once, with landers very similar to what you see above stacked six high with stack separators between each and an orbital maneuvering stage with lots of Dv for multiple plane changes. The mission was to do a large number of science experiments in every Mun biome in one trip. I looked for the screenshots, no luck. I have too many KSP screenshots.

[dire]

A sat with a single rated antenna has the power listed for the antenna. Two satellites with a single 100g relay dish each can always talk from Jool to Kerbin, and a probe with a 100g direct link can always talk to KSC if it has line of sight.

2 identical dishes have a power of 1.68 times a single dish, and 4 dishes have a power of 2.8 times a single dish. So four 15G communication dishes on one sat have a range of 42 gm, which if I recall covers everything but Jool and Eeloo.

With 20 x 100GM satellites, you'd have a power of 945 GM and you'd be able to talk to a level 3 tracking station from 486 GM or to a probe with NO antenna and only the 5k onboard from about 68 MM - within the kerbin SOI, for example.

Note that "What you can talk to" depends on the power of BOTH vessels (or the vessel and the tracking station), so if both vessels have the same power, the rated power is the range they can talk. It's reasonably accurate over close-ish values to take the average, but the actual math is the square root of (the first vessel's power x the second vessel's power).

Edited September 2, 2019 by dire