Close encounters: how do I get a planetary encounter with a periapsis low enough to aerobrake?

[TheEndHathCome]

Hey guys,

I need a hand aerobraking. I can't find any good tutorials, so I turned to the forum. 

When I get a planetary encounter, the periapsis is always thousands of kilometres above the planet. How do I get the encounter close enough to aerobrake?

[Superfluous J]

Drop a maneuver node somewhere between you and your target. Like, if you're going from Kerbin to Duna drop one on your orbit line about halfway there, in Sun orbit.

Then get your camera focused on Duna but have the node visible in the background, and then just... well... fiddle with it. Try all 6 directions, and see what that does to your trajectory. After a while you'll get a feel for what does what, and how to get as close as you'd like.

One big benefit here is Precise Node or Precise Maneuver, two mods which let you step through exact numbers (and fractions) of meters per second in each direction.

[TheEndHathCome]

Thanks! I'll try that.

[bewing]

On the other hand, these guys are all addicted to maneuver nodes. At your midcourse correction point, you can just look with your eyeballs at the trajectory past Duna (or wherever) and do the burns by hand. The required burns are tiny -- so throttle your engines all the way down to give yourself the required precision. Normal/antinormal first, to get your trajectory to pass over the equator (e.g. if your trajectory is too far north, then burn antinormal). Then prograde/retrograde to change the timing of your encounter, which is the easiest way to adjust the flyby Pe. (You have to be able to judge whether your craft arrived "too late" after your target CB already passed by.)

 

[Kryxal]

I find a combination of radial in/out and prograde/retrograde of more use for fine-tuning the encounter timing, specifically for encountering (or avoiding) moons.  Straight prograde or retrograde is simpler if you don't care about the details of WHEN you get there, but going to Laythe you're better off catching it when you hit periapsis, and only a few degrees inclination.

[Gargamel]

You also don't have to get it perfect, even at your mid  course correction.   Just get it close enough if that's the best you can do, and wait till you cross the SOI of the planet.   Then you can immediately tweak your inclination if needed, and fine tune your periapsis. 

[Geonovast]

This where tuned-down RCS really shines.

[Xd the great]

I usually do the correction burn at the edge of the planets SOI. It allows for better precision and larger error tolerance, at the cost of 10 d/v