Most efficient intercept: high or low?

[sevenperforce]

This has probably already been answered here and there, but a search didn't turn anything up, so....

I've been flying basic  Mun missions over and over with slightly different parameters to get the hang of it, and I wondered something. When you're plotting the Hohmann transfer, is it more efficient to aim at the L1 point (just at the very inner edge of the Mun's SOI) or as close to the Mun's orbital distance as you can? In other words, is it better to do the capture burn from the edge of the SOI or from as close as possible to the Mun's surface?

My inclination (no pun intended) is to think a close burn is more efficient, thanks to Oberth. But I'm not sure how the SOI patched conics really affect things.

[foamyesque]

As low as possible for your capture burn, but inclination changes are best done as slow (i.e. high) as possible.

[GoSlash27]

sevenperforce,

Is it your intention to enter low munar orbit? If so, then you want your Hohmann transfer to put you at that altitude.

If you're looking for the gate munar orbit, I'd have to calculate that.

Best,
-Slashy

[sevenperforce]

Looking for a landing.

And yeah, I just ran the mission again, and the difference was stark. I had been doing the minimum possible burn to reach the munar SOI and then doing a capture burn at that very high periapsis. This time I did a larger LKO burn to bring me to a 6 km munar periapsis and basically just did a suicide burn from there, and I ended up with almost twice the fuel reserves on landing.

[Aegolius13]

Yeah, low intercept is the best.  Re: the direct suicide burn, note there's really no penalty for circularizing your munar orbit before you start your descent, if you want to pick a different landing site or just park for a while.  (If you go straight from a flyby to a landing, you'll briefly circularize anyway.)  On the other hand, there's also no downside to going straight to landing, provided you're happy with the spot.  

[GoSlash27]

I'd say we can call this one answered

-Slashy