Free Return Trajectory via Minmus from Low Kerbin Orbit?

[StevieC]

What delta-V is best and when should I fire my engines, and how high above Kerbin should my starting orbit be?

[legoclone09]

You should only need about 860 m/s of delta-v in a LKO, and the apoapsis should be about 14,000,000 meters. The trajectory should show it going around the Mun and back to Kerbin. Be sure to practice in Sandbox with patched conics though!

[KerikBalm]

He said minmus... not Mun.. I've never tried a free return with minmus... requires too much precision, and its not like insertion and the return burn use a lot of dV anyway... so I really never bothered.

I only did free returns for mun flybys in career before unlocking the next node.

Now that I try mun flybys before I even have maneuver nodes... free return trajectories are out again for me.

[Empiro]

I remember doing it once as part of the old Mission Control contracts. It's possible, but you'll need near perfect precision. You need to burn so that your AP is past Minmus, and you pass through Minmus in front of it. You'll want to start as low as possible, and you'll need to use maneuver nodes (PreciseNode is a near must to).

[Wcmille]

If you launch from KSC when KSC is at the Minmus-Kerbin ascending or descending node, you can launch into the same inclination as Minmus without much extra work by aiming for 84 degrees or 96 degrees during launch (depending on the node). Once you have the same inclination, free return works just like Mun and is easy to find through trial-and-error with Maneuver nodes.

It is typically most fuel efficient to circularize as low as you can. I like to use 75km as my launch orbits, because I like a little margin above the atmosphere.