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How do I change inclination


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There are three parts to each node:

  • Prograde :prograde: or retrograde :retrograde: which will directly change your orbital velocity- burning prograde makes you speed up, retrograde makes you slow down. Use these to increase or decrease your orbit’s apoapsis or periapsis e.g. to fly from Kerbin to the Mun. Prograde will increase your altitude 180 degrees around your orbit from where you are while retrograde will decrease it.
  • Radial in :antiradial: or out :radial: which will change the shape of your orbit, but since they’re perpendicular (at 90 degree angles) to prograde and retrograde your orbital velocity will be unchanged. Think of them as “up” and “down” relative to your current orbit- burning radial in will decrease your altitude 90 degrees ahead on your current orbit but raise it 90 degrees behind, while radial out will raise your orbit ahead and lower it behind. Use these to move your apoapsis and periapsis around a bit e.g. if you’re getting a bit too close to the Mun at your closest approach, a bit of radial out will lift that periapsis away from the big scary mountains.
  • Normal :normal: and anti-normal :antinormal: which will change your orbit’s inclination- think of them as “left” and “right” when facing prograde. Burning towards normal will increase your orbital inclination towards 180 while anti-normal will decrease it towards -180, but there’s a catch: orbital inclination is measured from the point where your orbit crosses the equator, so to change your inclination to a specific value you need to do your (anti/)normal burn at the ascending or descending node, when you’re crossing the equator.

When you’re trying to burn radial or normal, you’ll need to add a bit of pro- or retrograde to it to prevent your orbit from getting higher or lower- this is because adding some extra momentum in any direction will change your overall velocity; prograde is the direction you’re travelling in, so if you add a lot of normal you’ll start dragging prograde to the left and increasing orbital velocity. The in-game tutorials might be of some help to you, but as with a lot of things in KSP experience is the best teacher. A mistake is only a failure if you don’t learn from it!

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One thing that's not been mentions is the Ascending and Descending Nodes on your orbit.  There are on the "mid point" of your orbital inclination and are the easiest ( least dV ) points at which to change your inclination.

As you experiment in orbital dynamics you will get a feel for this.  

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A good place to learn to use inclinations is going to and returning from minmus, try to set your orbit around minmus to be roughly at its equator before you reach it (middle of transfer basically), then do the same returning to kerbin. Minmus is on a tilted orbit, which makes this a good place to learn before heading to interplanetary inclination changes.

you might also notice its cheaper to adjust inclination mid transfer than from the orbit of another body (I believe its also cheaper to adjust inclination the further you are from the body your orbitting? not sure on this).

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1 hour ago, FusionNexus said:

you might also notice its cheaper to adjust inclination mid transfer than from the orbit of another body (I believe its also cheaper to adjust inclination the further you are from the body your orbitting? not sure on this).

The slower the orbital velocity, the less dV to change inclination, so yes, it’s cheaper in a higher orbit. In an elliptical “egg-shaped” orbit, ideally the An and Dn will be at the Pe and Ap. Since the orbit is slowest at the Ap, it takes less dV to change inclination there. 

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