Strange Orbit

[HerobrineLiu]

Hey guys, so I was just setting up a relay in high Kerbin orbit, and i created a maneuver node. Suddenly, 3 random predicted orbits appeared, and the apoapsis appears to be outside of Kerbin's SOI. Furthermore, I didn't even touch the node, meaning that the orbit should be unchanged. (Yes, I am a nub who uses MechJeb). Does anyone know what could've caused this? It's not really a problem. I couldn't get it to happen again. I'm just curious. 

https://imgur.com/q1ovg4E 

[KerikBalm]

Looks like a bunch of gravity assists from Mun

[Vanamonde]

Yep. Your path will be affected by Mun, but not beyond Kerbin's SOI. The projected path line would terminate at a point in space if that where the case. 

[4x4cheesecake]

1 hour ago, HerobrineLiu said:

I didn't even touch the node, meaning that the orbit should be unchanged.

In this case, your orbit will change anyway, thanks to the Mun, but just after one more orbit around Kerbin so KSP does not show you the Mun encounter yet. By adding the maneuvernode, the Mun encounter becomes visible because the game starts to calculate the next orbit and actually shows you the encounter with the Mun and how your trajectory will change in the future.

1 hour ago, HerobrineLiu said:

Yes, I am a nub who uses MechJeb

*Chookh chookh* Can you hear that? It's the wayne-train on its way to the mount whateverest If you don't want to participate in a challenge which prohibit this mod, you can do what ever makes fun to you^^

[Snark]

Moving to Gameplay Questions.

[Superfluous J]

Totally unrelated. If you take your imgur page and click the image to make it big, then right click it and "Copy image location", and then paste that here you get a nice picture so we can see it without having to go to imgur.

[HerobrineLiu]

12 hours ago, 5thHorseman said:

Totally unrelated. If you take your imgur page and click the image to make it big, then right click it and "Copy image location", and then paste that here you get a nice picture so we can see it without having to go to imgur.

Cool, Thanks!

Any idea why the apoapsis is outside Kerbin's SOI though?

Edited August 10, 2018 by HerobrineLiu
I forgot to add a space between word .--.

[4x4cheesecake]

8 minutes ago, HerobrineLiu said:

Any idea why the apoapsis is outside Kerbin's SOI though?

It doesn't look like the Ap is outside of Kerbins SOI. Like Vanamonde already said:

17 hours ago, Vanamonde said:

Your path will be affected by Mun, but not beyond Kerbin's SOI. The projected path line would terminate at a point in space if that where the case.

Kerbins SOI is 84,159,286m (very roughly twice the distance between Kerbin and Minmus)...what's the height of the green Ap?

[Superfluous J]

5 hours ago, HerobrineLiu said:

Cool, Thanks!

Any idea why the apoapsis is outside Kerbin's SOI though?

Oh sorry I thought that was answered. Things get crazy when you encounter other bodies orbiting the same body you're orbiting. However like Vanamonde I see no indication that the projected Ap is actually outside of Kerbin's SOI.

As to why it changed at all: KSP doesn't predict forever, just the "current orbit" from your ship. When you place a maneuver node, it forecasts the "current orbit" from that node which looks further into the future. Think of it as a "fog of war" type thing with only a certain visual distance. Your first Mun encounter is farther into the future than your ship can see, but not farther than the maneuver node can see.

[HerobrineLiu]

Huh, I was always under the impression that Minmus was about the edge. My maneuver nodes show an escape trajectory when I get past it. I learned something today!  (I'm also kind of ashamed I didn't learn it after 545 hours)

[Xd the great]

13 hours ago, HerobrineLiu said:

Huh, I was always under the impression that Minmus was about the edge. My maneuver nodes show an escape trajectory when I get past it. I learned something today!  (I'm also kind of ashamed I didn't learn it after 545 hours)

Thats the beauty of ksp. You play for 1000 hours and you still learn from it.

And if you wanrt to learn more about gravity assists, as in how to use the "strange orbit", to your advantage, it is really worth learning.

https://en.m.wikipedia.org/wiki/Gravity_assist

[Superfluous J]

14 hours ago, HerobrineLiu said:

Huh, I was always under the impression that Minmus was about the edge. My maneuver nodes show an escape trajectory when I get past it. I learned something today!  (I'm also kind of ashamed I didn't learn it after 545 hours)

While it's about twice as far as Minmus' orbit in distance, it's only about 20m/s of dV more burn from a 100km orbit. Or thinking in percentages, the burn to Minmus is about 98% of the burn to leave Kerbin's SOI.

So it is true, [#obiwan] from a certain point of view.

[HerobrineLiu]

4 hours ago, Xd the great said:

Thats the beauty of ksp. You play for 1000 hours and you still learn from it.

And if you wanrt to learn more about gravity assists, as in how to use the "strange orbit", to your advantage, it is really worth learning.

https://en.m.wikipedia.org/wiki/Gravity_assist

I’ve always wanted to attempt something like that, with Duna or Dres to shoot me towards Jool. Unfortunately, I’m lazy and bad at math so I just slap on more NERV engines and tanks instead. I’ve also noticed that gravity assists tend to amplify your orbital inclination. (Or it’s just Tylo.) 

[Xd the great]

6 hours ago, HerobrineLiu said:

I’ve always wanted to attempt something like that, with Duna or Dres to shoot me towards Jool. Unfortunately, I’m lazy and bad at math so I just slap on more NERV engines and tanks instead. I’ve also noticed that gravity assists tend to amplify your orbital inclination. (Or it’s just Tylo.) 

Yes, gravity assists can change your orbit inclination.

I suggest attempting a minmus return by a munar gravity assist. Should not be hard.