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kyler9437

90° Eastern orbit?

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kyler9437    2

For one of my contract I need to get a satellite into a really high polar orbit. And I thought that would be easy enough but when I zoomed out to see where it wanted it. The orbit is at a 90° Eastern orbit. I attempted it but failed horribly. I have no idea how I'm going to get this one done. Anyone have any ideas? 

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Snark    6695
13 minutes ago, kyler9437 said:

I guess the Eastern part I guess wasn't relavent but I need to do a polar orbit but instead of it being in line with the Kerbal base this one is running west-east along the polls.

Remember that the target orbit isn't attached to the planet.  When the planet rotates, the orbit doesn't.

So, the Kerbal "base" (i.e. KSC) isn't under the orbit now... but it will be in another hour or two.  Thus the instructions above:  all you have to do is wait a little while until the planet rotates to the point where you are directly under the orbit.  Then you're all set.

14 minutes ago, kyler9437 said:

I read somewhere that I could try and sling shot around the mun first but that seems a little excessive 

Yes, it would be.  :wink:   Massive overkill, when all you have to do is sit on the launchpad for a little while until the planet rotates you to where you want to me.

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LN400    292

Um forgive my ignorance but what is a 90 deg. eastern orbit? You mean the  orbit is 90 degrees from where KSC currently is? If so, wait  about 1/4 of a day or 3/4, and let Kerbin rotate KSC into position. If that's not it, a screenshot to show what a 90 deg eastern is.

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Snark    6695
1 hour ago, kyler9437 said:

For one of my contract I need to get a satellite into a really high polar orbit. And I thought that would be easy enough but when I zoomed out to see where it wanted it. The orbit is at a 90° Eastern orbit. I attempted it but failed horribly. I have no idea how I'm going to get this one done. Anyone have any ideas? 

Hello, and welcome to the forums!  :)

Can you specify what you mean by "90 degree Eastern orbit"?  I have no idea what you mean by that.

In general, it's not too hard to get to a polar orbit, it just takes a bit more dV than equatorial because you don't pick up that free ~170 m/s from Kerbin's rotation.

The main thing is, if you're aiming for a particular polar orbit, it matters when you launch (unlike an equatorial orbit, where you can launch any old time you like).  Here's how to do it:

  1. Launch your rocket to the pad, but don't take off yet.
  2. Timewarp until KSC (and therefore your rocket) is directly under the target orbit.  You'll have to wait 3 hours at most (half a Kerbin rotation).
    • Easy way to do this:  Switch to map view.  Double-click on Kerbin, so that the map view is centered on Kerbin itself rather than your ship.  Zoom out until you can see the target orbit.  Now rotate the camera until you're looking at the orbit directly "edge-on" so that it appears on your screen as a straight line passing through Kerbin's center, rather than as an ellipse.  Once you've done that, leave the camera in that position and time-warp until your ship is sitting right smack-dab on that line.  There, it's time to launch.
  3. When that happens, take off, but instead of making your initial gravity turn to the east as you usually do, you do it to the north or the south (which one will depend on which direction the orbit is traveling over your head as you launch).
    • Ideally you want to aim just a smidgeon westwards of due north or due south, like five degrees or so, in order to cancel out Kerbin's rotation.  But you don't have to nail it exactly-- the worst case scenario if you don't quite get it correct is that you'll end up in an orbit that's not quite perfectly polar, and then just have to spend a little bit of dV to correct it once you're in orbit.
  4. After that it's pretty much the same as matching an equatorial orbit.

 

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kyler9437    2

I guess the Eastern part I guess wasn't relavent but I need to do a polar orbit but instead of it being in line with the Kerbal base this one is running west-east along the polls.  I read somewhere that I could try and sling shot around the mun first but that seems a little excessive 

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kyler9437    2

I feel so stupid lol, this is a complicated game and I guess I was looking for a complicated fix. Thanks for the help on that one!!! 

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wumpus    494
13 hours ago, Snark said:

Yes, it would be.  :wink:   Massive overkill, when all you have to do is sit on the launchpad for a little while until the planet rotates you to where you want to me.

Depends how high.  This was even done (go out and loop around the moon to position a GSO satellite) in real life (around 2000 or so).  Obviously this is only a serious option if the "revert to launch/assembly" is grayed out and you have plenty of delta-v left on board.

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Snark    6695
1 hour ago, wumpus said:

Depends how high.  This was even done (go out and loop around the moon to position a GSO satellite) in real life (around 2000 or so).  Obviously this is only a serious option if the "revert to launch/assembly" is grayed out and you have plenty of delta-v left on board.

Yes, but one really has to know what one's doing to pull off something like that; it takes some experience.  To someone who's brand-new to KSP and hasn't learned all the ropes yet, like the OP here, it's probably best left for later.  :wink:

 

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