Satellite relay network question ( using RemoteTech 2 )

[bandi94]

Hy. I started playing in career mod few day's ago , after that i found this mod which gives a bit more realistic feel to the game. So i started experimenting with satellites to set up a stable connection around Kerbin. Now i did that with 4 satellites on a 1Mm Orbit they work very well i have no black-out or something similar. I did this with Communotron 16 ( Satellite-Satellite , Satellite - Command Center ) and Comms DTS-M1 for Satellite - Mun communication.

Now in career mode i don't have the Radioisotope Thermoelectric Generator ( almost the last part in tech tree) only Photovoltaic Panels so on the night side of Kerbin i am 100% on battery power so each satellite have 6 x Z-200 battery to have enought energy.

The problem is that i want to place 3 satellite on Mun orbit but the Mun have a bigger night side after a rough calculation i will need 10 x z-200 battery to have enought energy on the night side.

Is there any other orbit configuration to get a smaller night side or to get the smallest black-out spot possible. If not i think i need to rely only on the day side of the Mun and have a complet black-out on the night-side and use the flight-computer for all executions on the dark side.

Thx for any good tip .

Edited September 19, 2014 by bandi94

[Geschosskopf]

If you put your satellites in circular, equatorial orbits, then you're pretty much stuck with long nights. About the only way to avoid long nights is to use highly inclined, rather eccentric orbits with Pes at low altitude and Aps out there a good way. The satellite will thus spend most of its time above or below the ecliptic, out of all the shadows, and when it's down near the ecliptic, it's moving very fast so its night is short.

[Taki117]

Another option is to simply use bigger batteries. I'm not sure if you are using BTSM or not, but if now you could always use the Z-400 Radially mounted battery. Not only does it hold more charge, but as of .24 it is also physics-less.

[bandi94]

Thx for both of you. Well i think my first round of satellites will have more batteries , the eccentric orbit will need more sat sync to cover the Mun ( i think ) and how i am on the begin with the game i have all the chance to fail , anyway when i get more exp with the game i will send more satellites and try new thing's.

Well i dont use BTSM , but i use TecLife and MKS for the life support realism.

[yaur]

One trick is to drop com bases on the poles. in general these won't need to worry about night time (perpetual twilight) and can hit satellites beyond a fairly reasonable distance.

[bandi94]

One more question . I managed to put the satellites on orbit with a +/- 0.2m/s difference ( a personal record after a dozen of burns ) is this enough to keep them sync for some time or i will end up with a de-sync ? The distance between them is +/- 2.2Mm the Sat-Sat antena is a 2.5Mm range so i have a bit of gamble space.

Thx.

And i will study the pole positioning to.

[Taki117]

@Taki117 One more question . I managed to put the satellites on orbit with a +/- 0.2m/s difference ( a personal record after a dozen of burns ) is this enough to keep them sync for some time or i will end up with a de-sync ? The distance between them is +/- 2.2Mm the Sat-Sat antena is a 2.5Mm range so i have a bit of gamble space.

Thx.

And i will study the pole positioning to.

If they are all within .2m/s of each other they will oscillate in their orbits, but they shouldn't get out of position by too much. IF they do it's going to be years before they are far enough out to matter. If you have RCS on them you can fix their orbits easy enough.

[Kryxal]

Worry less about the actual speed, pay attention to the orbital periods, and you should be able to get it pretty much dead-on.

[Alshain]

Wait, the only way is highly eccentric orbits? That doesn't sound right. Correct be if I'm wrong but wouldn't a higher orbit also result in a shorter night/eclipse. A circular equatorial LKO is going to have a lot longer lack of sun than a circular equatorial geosync orbit.

[Kryxal]

A higher orbit means a lower orbital velocity, so the time spent eclipsed is longer ... but it's a smaller fraction of the orbit. I could see that altering due to the reduction in velocity normal to the Kerbol-Kerbin vector nearer the edges of LKO, though...

It might be interesting to make a formula giving the numbers for this.

OK, this seems to be the formula, note that arcsin is in radians, x is in km, and this is Kerbin-specific and above sea level:

((600+x)^3/3531.6)^.5*2*arcsin(600/(600+x))

The general formula is

2*arcsin(r0/r)*(r^3/GM)^.5

where r0 is the radius of the body, r is orbital radius (from center of celestial body), and GM is as defined for that body, and WATCH YOUR UNITS OF MEASUREMENT!

Side note: it looks like the local minimum for occluded time in orbit around Kerbin is at 129 km.

Edited September 19, 2014 by Kryxal

[Aedile]

For your power needs

Well, darktime in Mun orbit is not that much longer. Well it is, however you can be much closer for good coverage.

However also note that Mun will get eclipsed by Kirbin (for much longer than kirbin gets eclipsed by Mun), you can see how long that is by using Mun orbit stats.

The further from the planet you are, the longer battery life you need.

However it's much easier to keep them in sync.

I usually have omni antenna only sats pretty high (750 for momm16 or 2000 for comm32, which will allow for max drift before disconnect). Dish sats on polar elliptical orbit

You can do just fine

[bandi94]

Thx, that Plugin look's very useful. Well i have 4 satellites with comm16 orbiting kerbin at 1Mm , i want to place 3 more on Mun orbit somewhere around 750km ( i will use them for some rover's so if i will lose the signal somewhere on the back-side of the Mun it would be not a big problem) , after that place 2 more on a high kerbin orbit in range of the comm16 from the first orbiting satellites so it will be around 2-2.5Mm those 2 would be long range satellites picking signal from the lower orbiting satellites and relay the signal with long range dish, anyway on that orbit ( 2-2.5Mm ) i think 2 sats are enough to cover everthing without a black-out spot from kerbin blocking the signal.

P.S. I downloaded KS's modepack and it have some nice battery packets they look very nice on the sats. Slow i will send more and more sats to expand and make a stable connection.