How can i make my Orbit smaller?

[Remyyy]

So my Orbit looks like this (Blue) http://prntscr.com/hv8kif

and i want to get in the green one,

how can i maneuver in there?

[Reactordrone]

Burn retrograde until periapsis is touching the green orbit then orbit around to that point and burn retrograde again until apoapsis is touching the green orbit.

[XtraChrisP]

Try playing around with the maneuver node. Mixing a little radial in/out with prograde and retrograde may allow you to make the adjustment in a single burn.  I doubt this will be more efficient dV-wise, but you may find yourself in a situation (ie Kerbolar orbit) where waiting until you get to the apsides may not be very time efficient so it's always good to play around in local space where the stakes are low.  Just my $0.02

[monstah]

17 minutes ago, XtraChrisP said:

Mixing a little radial in/out with prograde and retrograde may allow you to make the adjustment in a single burn. 

I'm sorry, but since the orbits do not cross, going from one to the other in a single burn is impossible, you need at least one to intercept, and another one to rendezvous.

Learn the Hohmann transfer, that's your best friend for switching orbits

P.s. ok, a single burn is possible, but it has to be a looong burn like the Dawn spacecraft, and completely boring to do in the game...

Edited January 30, 2018 by monstah