Optimal Aerocapture and Aerobraking altitudes

[Whirligig Girl]

I'm trying for a Duna landing, what is the optimal aerobraking or capture heights?

[NoMrBond]

You need to get under 41,446 km to start aerobraking on Duna

Optimal is going to depend on how much weight and atmospheric braking you're going to apply though (with drogue shoot's or high drag parts like the B9 air brakes), you'll need to get to 10,000 or lower before even the drogue shoots will partially open.

Edited June 18, 2013 by NoMrBond

[Bunsen]

It's very sensitive to your entry trajectory and desired results, and there's no simple formula to tell you what periapsis altitude to target. Fortunately, some helpful person wrote a calculator that handles this stuff for you: http://alterbaron.github.io/ksp_aerocalc/

It can be fooled into giving you unreasonable answers, though, so check that its numbers make sense by comparing them to the atmosphere numbers on the wiki, etc.

[Vanamonde]

From a Kerbin transfer speed, 13,000m will drop you into a middling-height orbit of Duna. I don't remember the exact height that you end up, but it's around 40% of Ike's orbital altitude. It's a pretty small window, though. 12,000m is a ground impact and 15,000m is a fly-by on your way to interstellar space, so quicksave upon entering Duna's SOI.

Edited June 18, 2013 by Vanamonde

[Whirligig Girl]

I've set 14 km aerobrake.

[ZingidyZongxxx]

Just remember to quick-save so you can try it again if you mess up. You can also use Mechjeb (If you want) to give a good estimate of what your orbit will be after aerobraking with a certain periapsis.

[MOARdV]

Just remember to quick-save so you can try it again if you mess up. You can also use Mechjeb (If you want) to give a good estimate of what your orbit will be after aerobraking with a certain periapsis.

I'll second using MechJeb to provide estimates for aerobraking. No sense making wild guesses if you don't have to (unless you want to, of course).

[Mokmo]

Mechjeb aerobraking is very accurate mostly because it knows your specific drag coefficient. Don't forget to retract your solar panels!

[Thorbane]

Yes, forgeting to retract your solar panels turns aerobraking into aerobreaking.