Question moons orbit back to earth Leo using IMFD

Interceptor

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Hello,I don't have any problem launching from the moons surface,and getting back to my earth base using IMFD,but I can't figure out how to do it while in orbit around the moon,I always either end up far away from the earth,or crashing into the ground on earth,is there a good procedure?I just can not seem to figure out these steps using IMFD.Something I could print out would be great if possible.
 
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Hello,I don't have any problem launching from the moons surface,and getting back to my earth base using IMFD,but I can't figure out how to do it while in orbit around the moon,I always either end up far away from the earth,or crashing into the ground on earth,is there a good procedure?I just can not seem to figure out these steps using IMFD.Something I could print out would be great if possible.

I recommend using LTMFD for this. You can set a target perigee, and then you just perform an EOI when you get there.

It sounds like that its just your first TEI burn is just not accurate enough.

Which is fine. It is actually expected from IMFD, because of the other gravity sources, mainly the Sun, and the fact you jump from one sphere of influence to another, if you use IMFD you are gonna need to do a couple course corrections. When coming back from the moon you may have to do at least 2.

Open orbit mfd, and set reference to Earth. When the number on the center bottom turns green (which it will when it hits 0.50G, perform a mid course correction to set your perigee to what your target. LEO, say that is 220km.

You may need to do another one several hours later if it drifts too much. To see what your projected perigee with more accuracy, use IMFD's map program, set to MAX accuracy. It does a great job taking into all the gravity sources to figure out where you will end up. Orbit MFD is not nearly as reliable, you should only use it for that one number, the G number, which tells you when it becomes the dominate gravity source.

If you use LTMFDs TEI program and set it to orbit insert and not leave it in Reentry mode, you may only need to do one course correct. Or maybe not, if your projected Pergiee say, floats up from 220km to 350, or even up to 500km...that may not be a problem, you are still in LEO up there.
 
Hi Cras,I don't think LTMFD has an orbit insert feature for earth!but it does have one for LOI.Thanks for the answer.
 
You are right there is no Earth orbit insertion function like there is for the Moon, but you can program the TEI for orbit insertion, and then like SolarLiner said,you will need to use something else for the actual burn to circularize.

You can use IMFDs orbital program, the delta V program, you can use Burn Time Calc, all can help you do the orbital insertion burn.

Or Aerobrake, which is fun to do, I have done that before. I wanna say, usnig the XR-2, that I was able to perform a heads up aerobrake into LEO in two passes. Usually three. So many options. That is what makes Orbiter fun :)
 
The re-entry mode is gonna put you in a, 3 degree angle I think it is, into the atmosphere. Periapsis mode is gonna set up a fly by at that set altitude. It will be easier on your delta v for a Earth orbit insertion if you use periapsis mode.

However.......if you are using the XR-2 and are aiming for a direct return or want to try a single aerobrake pass, re-entry is the better mode.

I am afraid I dont remember the finer differences of the two modes since I have not used the perigee mode in a long long time.
 
Actually, periapsis mode is best for the XR direct re-entry. Re-entry mode will bring you in at about 6 degrees - far too steep for an XR.

Just set the PeA to about 72k and you'll be spot on for a direct re-entry.
 
OK,Thanks to you all for your advice,the LTMFD, periapsis mode in combo with IMFD works great for an earth orbit insert.:thumbup:
 
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