How to match orbit on contract (ascending node).

[rogerwilco]

Hi,

Love the game, but am getting very irritated on how to achieve the orbit contracts, the first time was Kerbin, which I tried and couldnt get to work, now I've made it to Mun (eventually, after hours) and still have some fuel left.

Unfortunately I've tried to match the orbits, but I cannot figure out how to change the timing of the orbit so that I match the contracts requirements.

You can see in my screenshot the contract requirements, I believe I should be within the minimal on Apo an Peri, as well as inclination (I had been 29.2 almost exactly but tried other things).

Please could someone help me with this? It's way past my bedtime!

Thank you!

Edited February 25, 2015 by rogerwilco

[Master Tao]

At the point where the orbits cross, you can burn radial in (directly toward the Mun) or radial out (directly away from the Mun). In the maneuver node editor, those will be the two blue adjustment handles.

Also, welcome to the forums!

[GoSlash27]

Ignore this. I gave you backwards instructions...

Best,

-Slashy

- - - Updated - - -

At the point after your apoapsis but before the target orbit's apoapsis, the orbits cross.

You need to burn radial out at this point.

Best,

-Slashy

Edited February 25, 2015 by GoSlash27

[TinfoilChef]

what i've been doing is a plane change at the point on my orbit that is closest to matching either the AN or DN of the target orbit. I also include a bit of radial in or out either at that point or at periapsis to move apoapsis and periapsis to where they need to be to match the target orbit.

That's how I handled couple of polar orbit contracts in this video:

[Kryxal]

As a rule, I just cross the orbit and set up a burn to match it ... it's far easier if you're in the same plane, since combining a plane-change with other things can be really annoying. If your AP and PE are in the same place and have the same value, you're done. Orbit mostly inside target means you need more prograde, then you adjust radial to make the orbits match better, rinse and repeat.

[Axelord FTW]

As Kryxal, TinfoilChef and GoSlash27 have said you need to burn radial (out or in, depending on which orbit crossing you are at).

Here's a handy visualization of how a node and a burn will take you from one orbit to the next (same OP).

The shown times are an example.

The orange line is the path your ship will have throughout the burn.

Blue is starting orbit, green is target orbit.

It's a good idea to visualize orbits as if they are road and you are a 2COOL2STOP Fast&Furious-esque driver. You need to drift them turns.

I'm a spatial guy so I have to work out everything in my head.

EDIT: This is assuming you are in the exact same orbital plane. If you arent, you'll have to drift along the radial/anti-radial vectors.

Edited February 25, 2015 by Axelord FTW

[rogerwilco]

Thank you so much everyone, I managed to do it like you said, Axelord your diagram was very useful.

I now have some spare cash again! I thought this mission was going to bankrupt me!