Ejection angles

[crazyewok]

Right I get the concept and Im great with phase angles.

But what a ejection angle in relation too?

What its point of origion on the Nav Ball or map? Were the 00 degrees line ?

[blizzy78]

The ejection angle is measured from a tangent at the current body's orbit. Check the right picture on http://ksp.olex.biz/

[crazyewok]

The ejection angle is measured from a tangent at the current body's orbit. Check the right picture on http://ksp.olex.biz/

So the orbital line prograde round the sun is the 00 ?

[blizzy78]

The heading on your navball has nothing to do with it.

[regex]

So the orbital line prograde round the sun is the 00 ?

The orbital line prograde of the body you are orbiting. Then you have angle from prograde (clockwise from 0) and angle from retrograde (clockwise from orbital line of the body retrograde from 0). E: Clockwise looking "down".

[crazyewok]

The heading on your navball has nothing to do with it.

If there any way too work it out other than by eye? Like a mod that adds a new ejection angle meter? Doing it by eye seem well rather low tec and crude....

Edited January 8, 2014 by crazyewok

[blizzy78]

Getting the ejection angle right is actually pretty easy, you don't need plugins to do that.

To practice, you can try setting up a maneuver node to go to the Mun: Pull out the prograde handle, until you get a nice periapsis at the Mun. Then grab the maneuver node by its central ring and drag it back and forth along the orbit. Observe how the periapsis changes its altitude, becoming lowest at exactly the right point. Drag the prograde/retrograde handles again to compensate for dV requirements. You may need to drag the maneuver node along the orbit again. It's a bit of wiggling.

When done, compare your projected trajectory with the current body's orbit. Notice how those are almost "parallel." That's what you need.

(This image shows a trajectory going from the Mun back to Kerbin, hence the retrograde ejection. But the basic principle is the same.)

Edited January 8, 2014 by blizzy78

[lajoswinkler]

If there any way tow rok it out other than by eye? Like a mod that adds a new ejection angle meter? Doing it by eye seem well rather low tec and crude....

It's Kerbal style.

Just wait for the approximate angle (I hold an actual protractor against the screen) and then drag the node along your orbit to fine tune everything.

[mediobogdum]

http://kerbalspaceprogram.com/0-18-1-kerbal-engineer-redux-v0-5/

[crazyewok]

Thanks for the anwers I think I got it now.

[ArmchairGravy]

http://kerbalspaceprogram.com/0-18-1-kerbal-engineer-redux-v0-5/

This mod is super useful. It gives you all the info you need to fly with precision.

[Tank Buddy]

To see the best ejection angle, retrograde for example, you would create a maneuver node on the western corner of the light side of body (in the case of a planet), or just by eye once you understand ejection angles; once the node is created, add some Delta V so you could easily see changes.

By moving the node around, you will see your orbit pivot and the Pe rise and fall. At the point where the Pe is lowest, you have found the best ejection angle for decreasing your altitude when escaping a body.

Moving the node to the opposite side and repeating with the Ap will show you the same.