An exhaustive list of synchronous, demi-synchronous, and quarter-synchronous orbits

[SkyRender]

Seeing as synchronicity is such a useful feature in orbits, I decided to compose a listing of the most common (1:1, 1:2, and 1:4) orbital synchronous periods. Hopefully it will help you out as you develop your satellite networks and the like! Disclaimer: some of these calculations may be slightly different from the wiki's by a few meters; this is mostly due to rounding error. The difference is generally about 0.00001% or so, which even in orbital terms is not very much.

Synchronous Orbits

Kerbin: 2,868,799m

Mun: Outside SOI

Minmus: 357,947m

Duna: 2,880,045m (unstable due to Ike)

Ike: Outside SOI

Moho: Outside SOI

Eve: 10,328,626m

Gilly: 42,139m

Dres: 732,257m

Jool: 15,010,755m

Laythe: Outside SOI

Vall: Outside SOI

Tylo: Outside SOI

Bop: Outside SOI

Pol: Outside SOI

Eeloo: 683,703m

Demi-Synchronous Orbits

Kerbin: 1,585,206m

Mun: 1,797,358m

Minmus: 203,290m

Duna: 1,695,902m

Ike: 666,215m

Moho: Also outside SOI

Eve: 6,247,599m

Gilly: 21,735m

Dres: 410,227m

Jool: 7,235,946m

Laythe: 2,767,221m

Vall: 2,152,598m

Tylo: 8,697,010m

Bop: Also outside SOI

Pol: Also outside SOI

Eeloo: 352,998m

Quarter-Synchronous Orbits

Kerbin: 776,594m

Mun: 1,058,257m

Minmus: 105,862m

Duna: 949,939m

Ike: 371,584m

Moho: 7,061,340m

Eve: 3,676,713m

Gilly: 8,882m

Dres: 207,362m

Jool: 2,338,124m

Laythe: 1,558,220m

Vall: 1,245,040m

Tylo: 5,256,750m

Bop: 987,926m

Pol: 931,900m

Eeloo: 144,666m

For those not in the know, synchronicity is when cycles match up. In orbital terms, a synchronous orbit is one where the same spot on the surface is visible at all times (commonly referred to as geosynchronous orbit here on Earth). Demi-synchronous passes over a given area twice per sidereal day, and quarter-synchronous four times per sidereal day. ("Sidereal day" means the actual time from mid-day to mid-day on a planet or moon.)

Edited August 31, 2013 by SkyRender

[Ignamious]

Great! Thanks for this. IT's already in my KSP Notebook.

[SkyRender]

Incidentally, I can calculate other synchronous orbits (ex. 1:3, 1:5, 2:3, 3:4, etc.) if anyone is interested. It's actually not very difficult since I have a spreadsheet set up for the lot of it. I literally just have to plug in two numbers at this point and I can get the full read-out of all possible synchronous orbits. If you want to calculate them yourself, here's the formula you need:

((6.67428e-11 * body's mass / (2 * pi / desired sidereal period) ^ 2) ^ (1/3)) + equatorial radius

All of the required values are on the wiki. To get the synchronous period you're after, multiply sidereal day by the appropriate fraction (so a 1:3 resonance you would multiply the sidereal day by (1 / 3), for example).

[Specialist290]

Nicely done! I'll be adding a link to this from the Drawing Board

[SkyRender]

Just for kicks, I calculated a bi-synchronous (2:1) Kerbin orbit: 4,906,376m. As you can imagine, the majority of planets do not have bi-synchronous orbits available. Unsurprisingly; many don't even have 1:1 synchronous orbits! Kerbin's spin is so fast, however, that you can go up quite a ways in terms of multi-synchronous orbits. The Mun occupies the sextisynchronous (6:1) orbital position, for example.

[Estel]

can we see the spreadsheet? i really need 4:3 orbits for all bodies with synchronous orbit and 5:6 orbit for all bodies with only demi synchronous for my remotetech constellations

[SkyRender]

can we see the spreadsheet? i really need 4:3 orbits for all bodies with synchronous orbit and 5:6 orbit for all bodies with only demi synchronous for my remotetech constellations

Sure. It's an OpenOffice spreadsheet, so you may need to convert it to get it to work with Excel.

EDIT: Also, for your particular orbits, you're not thinking with fractions there. What you really want is the 5:6 resonance of a 1:2 resonance. That's 2.5:6, I believe. And if you want a 4-satellite geosynchronous array, a 3:4 resonance would be faster to set up than 4:3.

Edited September 4, 2013 by SkyRender

[Estel]

Sure. It's an OpenOffice spreadsheet, so you may need to convert it to get it to work with Excel.

EDIT: Also, for your particular orbits, you're not thinking with fractions there. What you really want is the 5:6 resonance of a 1:2 resonance. That's 2.5:6, I believe. And if you want a 4-satellite geosynchronous array, a 3:4 resonance would be faster to set up than 4:3.

Thanks,ill make good use of this

[Sorcie]

Thanks for this, found via google search. <3

[Kerbal01]

this should be stickied.

[Guest]

Eve:

In the wiki:

On the sidebar, Synchronous orbit is 10 328.47 km.

In text: A synchronous orbit of Eve requires an altitude of 10373.195 km and a velocity of 858.95 m/s

(Engineer states that orbital period is 3d4h30m for that orbit)

In-game data states that Eve rotational period is 3d4h21m, but is it star day or solar day?

OP: 10,328,626m

Looks like value stated in the OP is much more accurate.

 

 

Edited January 8, 2017 by Guest

[Sharpy]

Any chance for Pe altitude of orbits resonant with these with either 2/3 resonance where possible, or 4/3 where the former would lithobrake?

Say, I want to deploy three relays into a demi-synchronous orbit of... uh, let's pick Vall. The craft carrying the three brings them into an orbit of Ap: 2,152,598m  and Pe of (some X) that has a period of 2/3 of the demi-synchronous. Then, each time I reach Ap. I release one satellite and circularize its orbit. As result, I have three evenly spaced relays.

[SkyRender]

This was actually done quite a long time ago!  Since then, I made an online version that's more flexible: http://www.skyrender.net/ksp_sync_calculator.html

EDIT: Sharpy, your question is easily answered with my online calculator!  Just plug in Vall as the body, 1 as the numerator, 2 as the denominator, and 3 as the satellite count.  That gives you a counter-sync height (ie. the lowest point you'll have to go to get them evenly spaced) of 879,086m.  Ie. put your apoapsis at 2,152,598m and periapsis at 879,086m, then boost each satellite after another of their full orbits up to a circular orbit at apoapsis.  I've tested it before and gotten perfect results every time with this calculator, so it should work for you too.

Edited January 19, 2017 by SkyRender