Geostationary Orbit

[LethalDose]

...Your orbit just needs to have a 6 hour period.

Pretty much this.

If the orbit isn't circular, the satellite will appear to move (librate) east to west and back during 1 day. If the orbit isn't equatorial, the satellite with appear to librate north to south and back during a day.

So, for commsats, you really don't need a perfectly circular orbit and it doesn't need to be equatorial. You just need a 6 hr orbital period.

[juvilado]

thanks for the info. Of course i knew there is a wiki with the data, i just wanted to know HOW to calculate it. :-)

[Robbii6]

If you want to know how to do it go here----> EPISODE 2---- http://forum.kerbalspaceprogram.com/threads/77169-Life-in-a-day-Jeb-%28EPISODE-2-out-now%21%29

[Claw]

thanks for the info. Of course i knew there is a wiki with the data, i just wanted to know HOW to calculate it. :-)

http://en.wikipedia.org/wiki/Geostationary_orbit#Derivation_of_geostationary_altitude will show you the math.

With the key equations being:

The product GM is known with much greater precision than either factor alone; it is known as the geocentric gravitational constant μ = 398,600.4418 ± 0.0008 km3 s−2 (note that this value is specific to given body).

The angular speed É is found by dividing the angle travelled in one revolution (360° = 2À rad) by the orbital period (the time it takes to make one full revolution). As an example, in the case of a geostationary orbit for Earth, the orbital period is one sidereal day, or 86,164.09054 seconds). This gives:

So, for any given body you need to know μ (or at least it's M) and the sidereal period. Also note the resulting radius is from planet center.

[Darkmatterhorizon]

But there are other options, like Molniya or Tundra orbits, that work just as well in KSP. When I get RT set up in 0.24, I want to try them.

I'm a fan of Molniya orbits for my Kerbin comsats in RT. They are extremely forgiving of not being perfectly aligned, since most of the time spent in each orbit is above the KSC horizon, you have to seriously get out of position before you need to adjust anything. Most of the orbit is high enough above the Sun-Kerbal plane that you'll need fewer batteries for the darkout periods. You also get a decent amount of overlap with three orbits, so even if you do get out of position or run out of electrical power without noticing, it's likely that you'll still be able to phone home on one of the other two sats.

[Mathman]

I know this is an old post but perhaps someone will read it.

First, What I love about KSP is how it gets people interested and involved in orbital mechanics, i.e. MATH.

Now - many of the posts to the question had a lot of good information. One addition to the answer to clarify some minor points. A geosynchronous orbit is one which has a period equal to one sidereal day (the time it takes Kerbin to rotate once in reference to the stars) and is 6 hours. This is not the time between one noon and another. On earth, a day is the time between one noon time and another and a sidereal day is a bit less than that. In KSP the time between two noons (solar day) is 6h and about 50 seconds. [ check the link to get more info] So yes, a geosynchronous orbit has a period of 6 hours.

A geostationary orbit is a special case where not only is the period equal to 6 hours but the orbit is equatorial and circular, giving it an angular velocity equal to the surface of the planet. The satellite would appear from the ground to always be in the same location in the sky. Don't you just love math?

- - - Updated - - -

so i can only get in to a Kerbostationary orbit at 2868.75 m. Which is when my angular velocity is 0.

Does it matter if its on a polar or equatorial orbit or any in between?

For a kerboSTATIONARY orbit, the orbit must be equatorial and circular. However, a larger set of useful orbits are so called kerbo-SYNCRONOUS where the position of a satellite returns to the same point in the sky at least once a day. They can have non equatorial orbits. Sometimes useful.

There are also polar orbits, solar synchronous orbits, 'Molniya orbits (a semi synchronous elliptical orbit), a whole passel of different orbit types which are useful. Try looking them up some day.

[carlorizzante]

There was a very useful table of the orbital periods and altitude of Kerbin.

Did they remove it from Wikipedia? Can't find it any more :-(

Edit: I finally found this - http://wiki.kerbalspaceprogram.com/wiki/Tutorial:_Basic_Orbiting_%28Technical%29

Edited June 21, 2015 by carlorizzante

[ajburges]

Any low thrust engine works. Even better than RCS. I used a LV-1 at 6% engine limit to tune my Keosynchronus orbit. 0.0 m/s surface velocity at every point of the period.

[Dr.K Kerbal]

Cool! My dad gave me a challenge to put a probe in a kerb geo stationary orbit so I came here to get answers. I answers I have got!

[ineon]

@Dr.K Kerbal - just be aware that this thread is mainly from 2 years ago, and some of the info may be out of date. I don't think anything specifically about kerbostationary orbit has changed, but atmospheric density and drag has changed a lot since this thread was originally posted so getting out of Kerbin's atmo may be significantly different.

[Stone Blue]

On 9/24/2013 at 2:26 PM, ArmchairGravy said:

I highly recommend putting on RCS thrusters. Trying to get that exact speed without them...

 

On 9/24/2013 at 2:55 PM, Meithan said:

I just learned about that last night while spending a good hour trying (and failing) to get the altitude just right with the ship's main engine. RCS thrusters are a tremendous help.

 

On 4/14/2014 at 6:11 AM, Red Iron Crown said:

The ion engines work well for this, too. Don't even need a big solar array as the burns are short enough for batteries to cover it.

Not sufficient for geosynchonicity. Orbit must be circular and equatorial as well.

RCS thrusters also have have the ability to change limits... And I'll add that, rather than changing limits on several RCS thrusters, I found placing a single Ant engine is even more "fine-tuned" and I can get even closer to a perfect orbit.... (I havent tried ion engines yet...Maybe this discussion will give me reason to try now...)

 

I'll also state that KEO orbit seems to be: Kerbisynchronous Equatorial Orbit (KEO) has a circularly uniform altitude of 2 863.33 km and a speed of 1 009.81 m/s, and NOT 2868.75/1009.0m/s, as I had always thought for a long time...

Edited January 21, 2016 by Stone Blue

[Dr.K Kerbal]

Dont worry. I tried it today and im only one second off.

[MrCamoga]

On 20/1/2016 at 1:49 PM, Stone Blue said:

 

 

RCS thrusters also have have the ability to change limits... And I'll add that, rather than changing limits on several RCS thrusters, I found placing a single Ant engine is even more "fine-tuned" and I can get even closer to a perfect orbit.... (I havent tried ion engines yet...Maybe this discussion will give me reason to try now...)

 

I'll also state that KEO orbit seems to be: Kerbisynchronous Equatorial Orbit (KEO) has a circularly uniform altitude of 2 863.33 km and a speed of 1 009.81 m/s, and NOT 2868.75/1009.0m/s, as I had always thought for a long time...

I have a geostationary orbit with a crcular orbit of 2.863.334m and the navball says that I'm going at 0.2m/s relative to the ground. My inclination is practically zero, what could I be doing wrong? 

Edit:

np I ended up matching exactly the orbit in the save file

Edited May 1, 2016 by MrCamoga

[KSPISAWSOME1]

Do you know how many meters it is?

[Dark Lion]

Is geostationary altitude at Kerbin really 2,863,334m? I didn't pay much attention to more than my orbital period and station-keeping, relative to the surface, but I seem to remember questioning the Wiki afterward because I still needed minor correction burns at each apsis to circularize the orbit with a perfect 6 hour orbital period... but I'm kind of OCD about that, so maybe Kerbal Engineer Redux isn't accurate? Stock KSP won't tell me my orbital period unless I'm EXACTLY at an apsis or maneuver node, so I really just don't know. I'm far too lazy for all this complicated math! I think hard enough in planning and assembly of these crazy contraptions...

[monstah]

1 hour ago, TheLionsBite said:

I still needed minor correction burns at each apsis to circularize the orbit with a perfect 6 hour orbital period...

Kerbin's sidereal day is around .09s shorter than 6 hours, you have to synchronize to that

Also, using KER, just synchronize the period and forget about the altitude (well, just keep it roughly circular). You can later circularize it perfectly by burning radial in/out when the probe crosses the average altitude to cancel it's vertical speed, and the period is unaffected.

[bewing]

Perfect circular orbits make some of the orbital calculation algorithms freak out. To keep the game stable, I don't recommend them in general.

[NumlockHolmesBR]

I used some mods to accomplish the image below (its not actually perfect, but is on the decimeter mark), and they are:

• MechJeb2 (pointing me to the right direction, and limiting my engines to as low as 0,000001m/s)
• Kerbal Engineer Redux (for detailed orbital info)

First, I used MechJeb to create a maneuver node to put my inclination to 0º, which wasn't perfect (but still useful to know WHEN to burn), than I created it again to kown when to burn and burned  manually by using  the tool "Limit acceleration to:" under "Utilities" on MechJeb to block my acceleration to 0,00001 (or something like that), once my inclination was non existing i rose my apoapsis and then my periapsis using a very, very low acceleration (thanks MechJeb) to fine tune it, than maneuver node again, this time to semi-major axis, manual burn, increasing the acceleration restraints on MechJeb until it was on the spot.

 

Results?! See for yourself :3

Again, not a PERFECT geosynchronous, but a REALLY close one, the best I could do with lots of tools in my hands, maybe a better orbital information mod....

[Rayder]

The data for a geostationary orbit around Kerbin is as follows:

Orbital Period: 5h 59m 9.4251830898s
Semi-Major Axis: 3,463,334.059488768

Using KER will get you extremely close but for perfect results either edit the save file, use Alt+F12 or HyperEdit.

Edited January 3, 2018 by Rayder

[ConArt70]

So the mission I have to do requires a keosynchronous orbit. I can't remember the exact inclination but at a rough guess it was 45 degrees. Is this possible? Reading the comments it appears so, i just assumed it  meant stationary over kerbin.

[bewing]

1 hour ago, ConArt70 said:

So the mission I have to do requires a keosynchronous orbit. I can't remember the exact inclination but at a rough guess it was 45 degrees. Is this possible? Reading the comments it appears so, i just assumed it  meant stationary over kerbin.

Welcome to the forums. There is a difference between synchronous and stationary. "Synchronous" just means it has the same orbital period as the day length of the celestial object being orbited -- inclination and eccentricity don't matter. "Stationary" means that it seems to hover over one point on the equator.

The game gives you both types of contracts occasionally.

 

Edited September 10, 2019 by bewing