Question IMFD Orbit Eject program

[Cris]

The question is: How can i actually use the orbit eject program in combination with another course program?

Things go like this for me, on a earth to moon transfer(i'm already in LEO):
-i start imfd (version 5.3b, i might add) in the left mfd
-i open imfd in the right mfd
-i share the left mfd, using id 1
-i go into the course program of the left imfd, select target intercept
-i make sure the reference is set to earth, source is myself, and the target is the moon
-i also select a two plane transfer because i feel like it (selecting an off plane transfer produces the same result as far as my problem is concerned)

(by this point, the left mfd is already displaying an intercept course, a time to burn, and a burn time. If i were to select autoburn, everything would work out beautifully, and i would be on my way to the moon with almost no mid course correction burn needed)

-next, i try to do what the tutorials advise: i go to my right mfd, and select orbit eject
-i change "higher orbit" or whatever is displayed at first, to "course"... and thus getting a "no course data is available" (again... something along those lines)

There are a couple of strange things that happen as well:
-if i go to the course page in the right mfd, i see the exact trajectory that i planned in the left mfd, meaning that the two mfds actually communicate data (if i zoom in the right mfd, the left one zooms also, for example)
-the map display in the right mfd also shows current course data if i switch it to plan mode
-if i do things like in the "Europa to callisto" tutorial (available on the imfd page), everything works ok (the orbit eject program in the right mfd receives data from the course program in the left mfd)

So... What am i doing wrong? Why are the tutorials working, but what i'm doing isn't? Why am i supposed to use the orbit eject program, when the target intercept program works just as well?

Thanks.

 

[Evil_Onyx]

I may be wrong, but IMFD see's a Earth to Moon flight to still be in Earth's SOI. as in you are going from a lower orbit around earth to a higher one the intersects with the moon.

A Europa to Callisto you are going from an orbit around Europa to and orbit around Jupiter then on to an orbit around Callisto. So an Ejection burn is required to leave Europa's SOI, but in the Earth/Moon flight you don't need to leave earth SOI.

The orbit eject program is used to go from one planet to another, (or another moon as with jupiters moons) not to go from a planet to a moon,

Hope this helps

 

[Cris]

Well, imfd actually shows the moon as being out of the earth's soi (not by much, but it is). I tried planning an earth to moon transfer in the same manner that was described in the europa to callisto" tutorial, and orbit eject got the flight plan from the target intercept program.

Btw... forgot to mention this: i have tried what i described above both with imfd 5.3b, and with imfd 4.2.1. Same results.
Also, this thread is not only aimed at helping me. I hope anyone that reads this thread will get a little info on how imfd actually works.

Thanks for the reply.

 

[Evil_Onyx]

IMFD uses a multi-body calculation to work out the best trajectory for a given situation, as takes in to account the effects from all the bodys that can effect, in the case of a Earth to Moon flight it uses Earth Sun Moon and Jupiter as affecting your trajectory (if you look on the map-config page of the map page you can find out how many bodys IMDF are taking in to account). IMFD Map page shows the SOI (gray dashed line) at the point where the major reference changes (ie. where the refrance changes from one body to another) not where the planet's ability to affect your trajectory.

Why are the tutorials working, but what i'm doing isn't?

I believe that some of the documentation is from previous versions which is why it may not be completely accurate.

Why am i supposed to use the orbit eject program, when the target intercept program works just as well?

You use the orbit eject program to execute a precise burn (it can save you some DV if you are going for a long trip) to leave a planets SOI, you still need to plan an intercept for the eject program to work properly.

 

[markl316]

Orbit Eject is designed for when you completely leave the planet's gravity (your course makes you leave the planet--your eccentricity will be >1). So Orbit Eject will work for going from Earth to Mars, Europa to Callisto, but it will NOT work the same for Earth to Moon. Have a look at this:

[ame="http://www.orbithangar.com/searchid.php?ID=4142"]IMFD Full Manual/Playbacks[/ame]

It describes how to get from the Earth to the Moon. You don't use Orbit Eject. Instead, you use only the course program and do a direct ascent, which is more awesome then ascent to LEO and then an eject burn

 

[Cris]

Thanks guys, that explains everything :thumbup: