Deploying 4 keostationary satellites in one flight

[kiwiak]

I thought about deploying 4 keostatonary satellites, separated by 90 degrees in one flight. Here is the plan. Circuralize on keo altitude, deploy first sat. Lower orbit to gain velocity, move ahead first sat a bit and burn pograde so apoapsis woudl be in same altitude as 1st sat, but separated b around 90 deg, than circuralize and release 2nd sat. And repeat for 3rd and 4th.

Question is what calculations do i have to use to calculate where shoudl i make my burns - how much angular separation shoudl i have from 1st sat during my burn.

Edited February 11, 2014 by kiwiak

[Fortunateson1969]

I think you're probably overcomplicating things. I'd only launch 3 satellites, with 120_deg separation.

Here's what I'm about to do for the second time. First, you launch. You can directly burn to 2868.75km, or do an apoapsis burn. Depends on where you want your satellites to "sit" (but I don't have much insight there...haven't done an AP burn, just the direct). Next, when you get to your new AP @ 2868.75km, you adjust your orbit so that your orbital period will resonate properly for what you're trying to do. I do four hours orbital period. Then, release your satellite and circularize it. Go back to your "shuttle" vehicle and complete a 4 hour orbit, then when you reach your apoapsis, release and circularize. Another rotation, and lastly another satellite.

RCS works well to get perfect Geo-sat maneuvers. I'm not 100% on the math for 90_deg, and I worked on it a bit. (You might try an orbital period of 1:30:00? That seems to work in my pen-and-paper simulations. I'm not sure if that's a proper orbit though.)

Sorry if this isn't helpful. Let me know if you have any other questions.

[Bean]

If you set up an orbit of apo 2868.75km and peri 1657.5km then release the sat at the apo and circularize you will end up with 4 sats 90 degrees apart

[Taki117]

In order for them to be truly in a synchronous orbit your orbital period must be exactly 6hrs. Your Ap and Pe are less important than your orbital period, but they should be close to 2868.75km.

[yaur]

This probably won't work because from LKO a 3:4 resonance will likely put you in the atmosphere (or lithosphere) so the way to really do this is to switch to

1) circularize at the desired orbit

2) release the first satellite

3) switch to a 5:4 resonance orbit

4) circularize at your next PE

5) repeat steps 4 and 5 until all satellites are deployed

MechJeb has a built in function to do this but there are plenty of calculators on the net to help you find the right ratio of SMAs (or you could do the math yourself http://en.wikipedia.org/wiki/Orbital_period)

edit: from a synchronous orbit you are probably fine going to 3:4, I believe the other direction is still more fuel efficient though.

Edited February 11, 2014 by yaur

[Navy2k]

Hi, why not just get an Orbit with an periapsis of 2868,75 km and an orbital time of 7:30h so you can drop an satelite every 7:30h and they will be apart 90°?

[KerbMav]

Actually, if you are placing satellites in sufficient number/altitude that they can always connect to at least there next neighbour, you will not need a synchronous orbit at all, they will just alternately link to KSC and distribute the signal through the network.

If you are using RemoteTech and playing career, the best available omni-directional antenna will let you get away with four satellites at a lower orbit (so they are not to far away from each other) that will cover most of the planet and connect your probe rockets at anytime during their launch and circularisation phase to KSC.

And yes, in such a configuration the most important thing is an equal orbital period. You may want to install VOID or KER which display periods to the fraction of a second and pack RCS in fine tuning mode.

[Javin]

Do you have any mods installed? I find getting a truly geostationary orbit without the aid of Flight Engineer is pretty much impossible. (Unless there's some other way to see your current orbit's period. I've not found it in the stock game yet.)

[TechnicalK3rbal]

Try watching Scott manleys video. He did three at 120 degrees, but I believe you should be able to do four at 90 degrees.

[kiwiak]

Thanks for advices, i might try your approaches tommorow.

I have engineer installed so there will be no rpoblem with that.

tehnicalk3rbal, do you mean interstellar quest?

[Alistone]

(Unless there's some other way to see your current orbit's period. I've not found it in the stock game yet.)

Subtract the time between Ap and Pe => double that time. That is your orbital period.

If you reach Ap in 5 minutes and Pe in 2 days 2 hours and 36 minutes then

your "half orbit" period is Pe - Ap => 2 days 2 hours 31 minutes.

Doubling gives your orbital period of 4 days 5 hours 2 minutes.

[TechnicalK3rbal]

Thanks for advices, i might try your approaches tommorow.

I have engineer installed so there will be no rpoblem with that.

tehnicalk3rbal, do you mean interstellar quest?

No, it was just a general tutorial-ish video. It's like 8 months old.

[CaptainKipard]

This might be useful.

[Kasuha]

1/ Get your apoapsis to approximately the stationary orbit height

2/ Time warp to the apoapsis

3/ Circularize to 6-hour orbital period

4/ Deploy satellite

5/ If you don't have any satellites left, deorbit and return to Kerbin

6/ Lower your periapsis and reduce your orbital period to 4.5 hours

7/ Time warp one orbit until you're at apoapsis again

8/ Repeat from point 3

Be warned - as far as I know, RemoteTech mod causes ships to randomly explode in 0.23. It should be ok if you run it under 0.22.