First time attempting interplanetary maneuver nodes - Could do with some help

[ActuallyImad]

It seems nomatter which maneuver buttons I edit to try and a decreasing apoapsis, even though Eve is targeted, my apoapsis is always in relation to the Sun, and not Eve. I've never gone interplanetary so there's obviously some things I don't yet know. I have tried different things to get the trajectory closer to Eve, and I've tried rotating the node around my orbit because I figured maybe I put it in the wrong place

[justidutch]

Your apoapsis and periapsis in the map view are always in relation to whichever body's sphere of influence you are in. If you do manage to get an encounter with Eve with your manoeuvre nodes, then you will also see Apo and Peri for Eve.

If you just launched randomly and tried setting up an Eve encounter, it may not be possible due to the way the planets are lined up. If you know that you are in a good launch window for Eve, then you should be able to get an encounter using the manoeuvre nodes.

To find out good launch windows, I use this tool:

http://alexmoon.github.io/ksp/

[Laie]

Placing maneuvers the "easy" way:

Put a maneuver on your orbit around Kerbin. If you have no outside knowledge to guide you, it's usually a good starting point to place it on the sunny side iof kerbin if you want to get to an inward planet (Eve, Moho) and the dark side if you want to go out (Duna, Jool).

Pick the planet you want to visit and make it your target.

Pull prograde until your projected trajectory around the sun about touches the target planet's orbit. You may already see the two markers denoting your position, and the target's.

If you do not yet see those markers, play around with normal ("up/down") to bring either AN or DN near the point where the two orbits meet.

Once you see the markers, you can refine your maneuver. If you find yourself adding a lot of radial to the burn, try to shift the whole maneuver a little.

Depending on when/where you start from, this refining can take ages... hence the quotes around "easy", above. And if you try to do it at the wrong time (as in month, not time-of-day), the resulting maneuver may be horribly inefficient. You are familiar with the concept of launch windows?

[ActuallyImad]

Maneuver node position

Eve position

My trajectory is always roughly that dotted purple line, can't seem to get it to 'shrink' inwards towards Eve.

edit: I've tried sliding the node to other positions and then altering it some more in different ways, no luck yet. It's always in relation to the sun.

[Rosco P. Coltrane]

Also, mind the inclination. You might have your Ap at the correct height, but you won't see encounter markers because your different inclination means you are way off up or down for the time you get there.

So, tip: you can add a maneuver node in your dotted projected orbit, and add normal/ant-inormal to go up and down and see if it gets you and encounter. You can always keep playing with your prograde in your original node and the one in the dotted line will update.

[phunk]

Put the maneuver node on the sunny side, around where those orbit lines disappear behind the planet on the right side in your "maneuver node position" image.

[ActuallyImad]

I've managed to get 'closest approach' markers and everything. I done that by first escaping kerbins sphere of influence, then making a 2nd maneuver, mainly using retrograde marker to shrink orbit. Think I've got this down

- - - Updated - - -

Wow maybe not. before my ascending node got anywhere near eve. The delta V requirement was 5k minimum, going upto 8k when trying something different with the node. Baring in mind that's not to encounter Eve, just to get A/N anywhere near it

[Rosco P. Coltrane]

Something's wrong there. Your projected orbit shouldn't be a lot bigger/smaller than that of the target planet. That's why your dV requirements are so big. The way you should do it, if you want to save fuel, is wait for the phase angle between you and the planet to be right. It will take time, but at the end you should be able to just place a node and burn some retrograde/prograde and be done. So it's a time vs fuel situation.

The way you do it is, you put a node somewhere in your orbit and add some prograde/retrograde until your Ap/Pe match the planet's orbit, and then you slide the node around (keeping Ap at the orbit) looking at the encounter markers to see if they get closer.

[Chewy]

I think I see the problem. You have two issues going on. One is that you're ejecting out of Kerbin's influence in the wrong direction. Two is that Eve is in the wrong position relative to Kerbin when you make your transfer

1. Once you are in low Kerbin orbit, you should make your transfer burn on the light side of the planet. Remember that Kerbin itself isnt stationary and has orbital velocity around the sun as well, so if you want to make a Hohmann transfer to lower your sun PE to Eve's altitude, you need to eject from Kerbin in the opposite direction to the direction Kerbin is orbiting the sun. Your transfer burn should therefore be occurring sometime between sunrise and noon. Adjust the position of the node so that your trajectory angle lines up with Kerbin's retrograde vector at the Kerbin escape point (you might need to zoom out to see Kerbin's path around the sun)

2. Since Eve is also in motion around the sun, you need to schedule your departure so that Eve happens to be near your PE (around the sun) around the same time you arrive there. Since Eve is in a lower orbit, it is traveling faster than Kerbin, so you need to leave when Eve is behind Kerbin by about 60 degrees. This alignment will allow Eve to catch up to you while you are in your transfer orbit.

You might also have to do an inclination correction at some point during the transfer (at the AN or DN). You should be able to get an encounter for less than 1500 m/s dv if you do these two things (less if you luck out with the inclination)