IMFD Course - Lunar return?

[jjake101]

How do I set up IMFD Course for a Moon to Earth flight? here is what i get when I try to set it up...

 

[Tommy]

You can't have the Target and Reference be the same - and you have both set to Earth. I'm not at home, and forget the exact setting, but I think you need to set the target to "e".

I recommend downloading "IMFD Full Manual and Playbacks" from Orbithanger - lesson four is a Moon - Flight. You can ignore the parts about a "magic number" if you aren't trying to perform a direct re-entry (the magic number is used to ensure you re-enter at a longitude that allows you to land on target). Just set TEj and TIn for a Time-Of-Flight of about 4.5 days for a low energy transfer. The TEj can be anything since the Moon is tidally locked - you only need a specific TEj if you want to reach Earth at a particular point. If you will be entering LEO before re-entering, TEj can be anything - but it helps to allow about 6500 seconds to give you time to reach lunar orbit (assuming you are starting from "landed")

 

[Tommy]

Not sure how I missed this yesterday, but you can't use Target Intercept to get from the Moon to Earth. You will need to use Planet Approach - I suggest setting the EqI to 30, the PeA to 500k (to leave some room for error, otherwise you tend to end up with a negative PeA when reaching Earth) and a TEj of 6400 (allows time to launch and reach the ejection point. Planet Approach can be set up while landed, and Surface Launch used to make the ascent. As usual, Orbit Eject is used to leave the Moon (not Planet Approach's AB).