Kerbin Semi-Synchronous Orbit altitude?

[Sippitous]

Just by looking at the parameters box that is available when you are focused on a planet such as Kerbin, Duna, Ike, or Eve (and others I assume), the info there is different. For Kerbin, I can only tell that the escape velocity is different. The mass may be different, but there may be a different rule for rounding cause 1.1.3 rounds to 3 decimals and 1.2 rounds to 2. For Duna, the mass is different, the GM is different, and the escape velocity is different. And Eve and Ike are different in similar ways.

 

[GoSlash27]

8 hours ago, Sippitous said:

Just by looking at the parameters box that is available when you are focused on a planet such as Kerbin, Duna, Ike, or Eve (and others I assume), the info there is different. For Kerbin, I can only tell that the escape velocity is different. The mass may be different, but there may be a different rule for rounding cause 1.1.3 rounds to 3 decimals and 1.2 rounds to 2. For Duna, the mass is different, the GM is different, and the escape velocity is different. And Eve and Ike are different in similar ways.

 

 Sippitous,

 If everything is different in a similar pattern, they've probably altered G. You should submit a bug report about it; a change there will skew the results of KER, MechJeb, and everyone who's ginned up spreadsheets.

 You may be in line for the chance to name something.

Great find!

-Slashy

[Rodhern]

11 hours ago, GoSlash27 said:

 Sippitous,

 If everything is different in a similar pattern, they've probably altered G. You should submit a bug report about it; a change there will skew the results of KER, MechJeb, and everyone who's ginned up spreadsheets.

 You may be in line for the chance to name something.

Great find!

-Slashy

Seriously?, you should submit a bug report that they changed parameters? [edit: yes, that one was a deliberate provocation for dramatic gesture].

That was a rhetorical question, what I am saying @Sippitous, is that you should check the change logs first, that you aren't just submitting that you have observed the intended changes to the game.

Edited September 24, 2016 by Rodhern

[Sippitous]

Kerbal should now be named McJebble! lol

[Rodhern]

2 minutes ago, Sippitous said:

Kerbal should now be named McJebble! lol

I didn't get that joke, could you explain it for dummies?

[Sippitous]

 @GoSlash27's recent comment about getting to name something. I was renaming something. Perhaps not that funny. 

[Rodhern]

5 minutes ago, Sippitous said:

 @GoSlash27's recent comment about getting to name something. I was renaming something. Perhaps not that funny. 

Ahh. Now I get it. Thanks.

[ recent experience shows that we sometimes need a little help to understand the funny in this thread ;-) ]

I also googled it in the meanwhile. I guess the "Kerbal" word made me miss the joke. Anyways, thanks for  explaining.

[Sippitous]

6 hours ago, Rodhern said:

Ahh. Now I get it. Thanks.

[ recent experience shows that we sometimes need a little help to understand the funny in this thread ;-) ]

I also googled it in the meanwhile. I guess the "Kerbal" word made me miss the joke. Anyways, thanks for  explaining.

Well, It didn't help that I spelled Kerbol wrong. Swing and a miss.

[Sippitous]

Guess this answers the question. From the devnotes: "...An example of these bugs people have found is the standardisation in gravity values to 9.80665, making the planet orbits shift ever so slightly and the geosync heights change - they’ll be back in their right positions..."

[Rodhern]

On 10/22/2016 at 9:14 PM, Sippitous said:

Guess this answers the question. From the devnotes: "...An example of these bugs people have found is the standardisation in gravity values to 9.80665, making the planet orbits shift ever so slightly and the geosync heights change - they’ll be back in their right positions..."

Steam just downloaded version 1.2.1 today. Seems you are right about the gravity. The Kerbin sea level gravity acceleration is back to exactly 9.81 m/s².

[Shikashi]

On ‎22‎.‎09‎.‎2016 at 4:06 PM, Sippitous said:

First thing first. I need to state my point. 

I BELIEVE THAT THE ALTITUDE OF A CIRCULAR SEMI-SYNCHRONOUS ORBIT AROUND KERBIN SHOULD BE: 1,581,516 M

 

@DrLicor  I understand all that. The difficulty of perfect precision is what I was sort of demonstrating. If you use the facts and numbers that all of us have accepted as true (such as the mass of kerbin, gravity at kerbin,rotational periods, etc) then the math points to an altitude height of what @GoSlash27 was saying:  1,581,745 m.  But, I am saying it should be 1,581,516 m. Not because of any math, but because when I physically (digitally) put a satellite in a circular orbit at the altitude of 1,581,516 m, it produces a semi-synchronous orbit that only shifts out of alignment 4 meters over the course of 10 years. That's very accurate. To demonstrate this accuracy I am going to digress for a bit. Time for some math.

 

A satellite in orbit around Kerbin at an altitude of 1,581,516 m  (taking into account Kerbins 600,000 equatorial radius) travels 13,706,869.27857718 meters every rotation (C=2πr).

C=2πr      13,706,869.27857718 = 2π(1,581,516 + 600,000)

 

A semi-synchronous orbit is 2 orbits per sidereal day. 

2 * 13,706,869.27857718 = 27,416,738.55715437 meters every day

 

Kerbin orbits it's star every 426.08 days

27,416,738.55715437 * 426.08 = 11,680,445,724.43233 meters every year

 

For 10 years

11,680,445,724.43233 * 10 = 116,804,457,244.3233 meters every 10 years

 

That a lot of traveling. And to be off by only 4 meters over that much time and distance is wonderfully accurate. if I wanted to adjust my orbit so that it was 100% accurate I would have to reduce my velocity by .000074707015747 m/s, which isn't possible in this game. (also, that's assuming I was at exactly 1,581,516.000000000 meters which isn't possible to determine. ooooh. maybe it is. I can pull the orbital info from the data files):

VESSEL
        {
            pid = e5bb18b8375041ed97456799c720ded5
            name = Semi Sync
            type = Station
            sit = ORBITING
            landed = False
            landedAt = 
            splashed = False
            met = 15542565.594103955
            lct = 1266696.2960705161
            lastUT = 16809261.91017447
            root = 0
            lat = 5.042437216409775
            lon = 14.704801337842444
            alt = 1581515.6353108771
            hgt = -1
            nrm = -0.59995234,0.0479642227,0.798596621
            rot = -0.306740254,-0.287918717,-0.899826109,-0.115439601
            CoM = 0.00144628342,-0.0832113847,-0.00246789306
            stg = 1
            prst = False
            ref = 0
            ctrl = True
            cPch = -0.08799998
            cHdg = 3.43
            cMod = 0
            ORBIT
            {
                SMA = 2181515.978894108 <-----------------------------------------that's pretty close 2,181,516
                ECC = 1.6117364556775186E-07
                INC = 54.999569826795124
                LPE = 178.55552523516766
                LAN = 299.9999740444099
                MNA = -0.082294934085444207
                EPH = 16809261.890174471
                REF = 1
            }VESSEL
      

 

So, back to my point. If I understand things correctly, then the altitude at which to put an object around Kerbin with a circular semi-synchronous orbit is 1,581,516 m which will have a velocity of 1,272.1 m/s. 

 

Ideas?......Thoughts?.....Agreements?.....Disagreements?

~KSP for life!

 

Not quite, a semi-synchronous orbit is half the orbital time of a synchronous orbit, when it doesn't move about the ground it's a synchronous orbit, or a geostationary Orbit

[Sippitous]

5 hours ago, Rodhern said:

Steam just downloaded version 1.2.1 today. Seems you are right about the gravity. The Kerbin sea level gravity acceleration is back to exactly 9.81 m/s².

I guess that scraps this discussion. I'm glad they fixed it.