# Are there AN and DN for Kerbin itself, when orbiting it?

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I want to change my orbit's inclination to, hopefully, make an orbit that crosses the poles (this is after I had already launched into an equatorial orbit, yes I know it's much easier and more efficient to launch directly into such an orbit). I know when you do rendezvouses in orbit, you can match orbit inclination by burning during an AN or DN. But if I'm just orbiting and want to change my orbit inclination, I can just do it at any time, yes? Or when I have an inclination that is > 0, does it become more efficient to burn at specific points in the orbit itself?

And another question regarding this - is it possible to make inclination change burns without affecting your AP and PE? When I tried, I inevitably stretched out my orbit height, even though I was burning at 90 degrees to my velocity vector and shouldn't have been adding any velocity to my orbit.

Edited by guitarxe
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Yes, set the Mun as the target. Since it is in a pretty much perfect equatorial orbit of Kerbin, you will have the AN/DN in relation to it available. Of course, if your circular, the AN and DN hardly matter for just inclination changes. You can really do it anywhere.

I gotta warn you though, changing from equatorial to poles in LKO is not just inefficient, it's VERY inefficient. You need to have a bunch of dV to do it.

Second question: yes and no. Your inclination change will always change AP/PE but you can counter the change by aiming it right. When you make a maneuver node you would change the inclination and then adjust the AP/PE afterward, you will see the direction you aim is not right on the Normal/Antinormal mark, but just off it to correct the eccentricity.

Edited by Alshain
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And another question regarding this - is it possible to make inclination change burns without affecting your AP and PE? When I tried, I inevitably stretched out my orbit height, even though I was burning at 90 degrees to my velocity vector and shouldn't have been adding any velocity to my orbit.

As soon as you start your inclination change burn, your velocity vector changes, so you would need to adjust your heading continously in order to burn at an angle of 90Ã‚Â°.

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Of course, if your circular, the AN and DN hardly matter for just inclination changes. You can really do it anywhere.

I believe you meant to say that an inclination of 0 means that AN and DN hardly matter. Inclined circular orbits still need to do inclination changes at the nodes.

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If you're already in orbit and do want to make a big inclination change, it takes less delta-V to raise apoapsis (eg to as far as Minmus), make the plane change at apoapsis, then lower your orbit again. Even less if you aerobrake back down.

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I believe you meant to say that an inclination of 0 means that AN and DN hardly matter. Inclined circular orbits still need to do inclination changes at the nodes.

Well, that was implied, he said he was already equatorial.

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And another question regarding this - is it possible to make inclination change burns without affecting your AP and PE? When I tried, I inevitably stretched out my orbit height, even though I was burning at 90 degrees to my velocity vector and shouldn't have been adding any velocity to my orbit.

Another option is to set up a maneuver so your final Ap/Pe is the same as your initial Ap/Pe, and then follow that maneuver. You need to mix normal and retrograde burn, the bigger the change the more retrograde impulse you need to keep them.

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1. For stock KSP - no, however you can use Mun, as it has 0 inclination.

If you are using KER (v1+), it tells you time to Equatorial AN/DN

2. Yes, burning normal, does not change your AP/pe. However burning Normal changes your inclination, and therefore your normal, thus if you don't turn, you also end up burning grade.

So you'll need a node with both normal and grade element.

Or you need a mod which will allow you to see where the normal is, or lock you to it (e.g Enhanced Navball, or kOS).

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