How do you launch to synchronous orbit with more than 1 launch.

[Athen]

So, I want to establish a 3 satellite synchronous orbit relay on kerbin (https://meyerweb.com/eric/ksp/resonant-orbits/), but I cant launch more that 1 satellite at a time. How do I time my launches correctly so that they reach synchronous orbit while maintaining a proper triangular positioning? 

[bewing]

Launch the sats exactly 2 hours apart, and perform precisely the same ascent each time. Then adjust the orbits to get them to have the correct periods.

[klesh]

5 hours ago, Athen said:

but I cant launch more that 1 satellite at a time.

 

How come? Have you unlocked fairings yet? There are a few methods to launch multiple satellites on the same ship and an interesting ballet to be performed which allows you to drop them off one by one at their intended positions. Most of those methods involve the fairing parts, and the truss structure and internal nodes to stack repeats of the same satellite on the same rocket. 

[FloppyRocket]

Or, you could launch the 2nd and 3rd satellites into slightly lower orbits than keostationary, wait until each drifts into the correct position, and then circularize.

Edited March 2, 2019 by FloppyRocket
typos are my friend

[Stone Blue]

While setup for remotetech, this also works for stock... and for moar than just comm sats... basically anything you want in a constellation

https://ryohpops.github.io/kspRemoteTechPlanner/

 

Basically, with multple sats on one launch, you need to setup a resonant orbit for the delivery vehicle.
That site displays exact parameters for for both Single & Multiple Launch missions. (kind of a misnomer, as Single/Multiple means for the payload vehicle...*not* for the sats/payloads themselves)

Edited March 2, 2019 by Stone Blue

[Athen]

7 hours ago, klesh said:

 

How come? Have you unlocked fairings yet? There are a few methods to launch multiple satellites on the same ship and an interesting ballet to be performed which allows you to drop them off one by one at their intended positions. Most of those methods involve the fairing parts, and the truss structure and internal nodes to stack repeats of the same satellite on the same rocket. 

My satellites i want to launch are a little too big for the nodes. At most i could launch 2 at a time.

[overkill13]

2 hours ago, Athen said:

My satellites i want to launch are a little too big for the nodes. At most i could launch 2 at a time.

Place a second fairing on the last node of the first fairing.  Place two sats between the fairing bases and the last on on top of the second fairing.  Build a fairing around all three sats from the lower base and leave the upper base without a fairing built on it.  Or create an interstage between the two bases and cap the top one with a pointy fairing.

[Superfluous J]

• Launch sat 1, put it in the orbit you want.
• Launch sat 2, put it in an elliptical orbit with Ap at the orbit of Sat 1. Then set up the first step of a rendezvous so on the next orbit, the 2 satellites are near each other.
• When they are actually near each other, burn with Sat 2 so that its orbit is 1/3 or 2/3 the period of Sat 1. 2/3 is easier. 1/3 may not even be possible.
• Next orbit, it will be in the proper place at Ap, so burn it into an orbit that matches Sat 1's in period.
• Repeat for Sat 3, but use Sat 2 as your reference point.

[Starman4308]

19 hours ago, bewing said:

Launch the sats exactly 2 hours apart, and perform precisely the same ascent each time. Then adjust the orbits to get them to have the correct periods.

That won't work for geosynchronous orbits. Spacing by a fraction of Kerbin's sidereal day works well for spacing longitude of the ascending node, but that's arbitrary for geostationary birds.

What does work is to initially place them into a resonant orbit, and circularize after different numbers of orbits. For example, if you did a 2/3 resonant parking orbit, one would circularize after two orbits, one after one, and one immediately on hitting apoapsis.

[pincushionman]

On 3/2/2019 at 9:51 PM, Starman4308 said:

That won't work for geosynchronous orbits. Spacing by a fraction of Kerbin's sidereal day works well for spacing longitude of the ascending node, but that's arbitrary for geostationary birds…

Why not? You’ll end up with three sats on the same orbit, spaced by 2 hours out of 6.

[GoatRider]

6 minutes ago, pincushionman said:

Why not? You’ll end up with three sats on the same orbit, spaced by 2 hours out of 6.

Think about it. Imagine you could launch it straight up instantaneously to keosynchronous orbit. 2 hours later, launch the next one- the first one is still straight up, since it's in keosynchronous orbit, so the second one ends up in the same spot. Then do it with the 3rd- you end up with 3 satellites in the same spot. Same thing will happen if you use a normal transfer orbit to get it there, it's just harder to visualize.

[Starman4308]

8 hours ago, pincushionman said:

Why not? You’ll end up with three sats on the same orbit, spaced by 2 hours out of 6.

Let's say you try this.

Your launch site has rotated by 120 degrees... but the first satellite has also rotated by 120 degrees. Both will end up looking at the same patch of Kerbin.

[pincushionman]

10 hours ago, GoatRider said:

Think about it. Imagine you could launch it straight up instantaneously to keosynchronous orbit. 2 hours later, launch the next one- the first one is still straight up, since it's in keosynchronous orbit, so the second one ends up in the same spot. Then do it with the 3rd- you end up with 3 satellites in the same spot. Same thing will happen if you use a normal transfer orbit to get it there, it's just harder to visualize.

 

1 hour ago, Starman4308 said:

Let's say you try this.

Your launch site has rotated by 120 degrees... but the first satellite has also rotated by 120 degrees. Both will end up looking at the same patch of Kerbin.

You guys are right! I tip my hat to you.

[bewing]

Yeah, you're right. Since the target orbit is synchronous, you will need to launch to a lower orbit and then raise your Ap and circularize with the proper timing.

[Kryxal]

I'd probably launch direct to required AP and a pair of 4-hour orbits for the first sat, direct to AP and a single 4-hour orbit then circularize for 2nd, and direct to AP and circularize for the 3rd.

On second thought, circularizing and changing your AP to that required for stationary/synchronous at a fixed point will probably work better.