IMFD IMFD Surface Launch question

[orbekler]

Hello, I have a question about the Surface Launch program of IMFD.
Scenario: XR-5 Ready for takeoff to the ISS (target changed to moon).
Guideline: IMFD Full Manual, page 93, Tutorial #2—Mars to Phobos
I activated the Surface Launch program, and following the tutorial, I waited until EIn was nearly 0.

Then I began the climbup with a heading of ~90°, and added side shift to mantain EIn=0.
LEO completed, RInc with the moon was about 25°.

The Course Target Intercept program set to Source-Plane calculated about 6.1k of total dV (PlC included, Off-Plane was about 13k - EjA~85°!!!).

I repeated once again the same Scenario, but this time I just used Map and Align MFDs, awaited when RInc was at his minimum (~5.8°, about 4 hours later than time indicated by Surface Launch), began climbup with a heading of 90°, and mantained RInc of about 5.8°.

The Course Target Intercept program this time calculated about 4.4k of total dV, making a pretty substantial difference in dV from the first try.

My question is: Surface Launch program should find the first best possible launch window, but just referred to the best latitude (BLL), or also from the current latitude? In this case, why RInc is much greater with Surface Launch?

Also, it seems there was a small difference between IMFD and Align MFD RInc (about 3° in the first example and 2° in the second).

 

[Tniffoc]

Sorry for the complete, but temporary threadjack, how did you change the color of your glass cockpit?

 

[Izack]

Sorry for the complete, but temporary threadjack, how did you change the color of your glass cockpit?

Alt+H. It's in the manual.

 

[jarmonik]

I activated the Surface Launch program, and following the tutorial, I waited until EIn was nearly 0.

You forgot to set the time of arrival (i.e. time of intercept) TIn. Also it is important that you use the same time of arrival in surface launch and target intercept program.

LEO completed, RInc with the moon was about 25°.

In the off-plane transfer the RIn isn't a critical factor but having zero RIn is good and it may save a little fuel.

The Course Target Intercept program set to Source-Plane calculated about 6.1k of total dV (PlC included, Off-Plane was about 13k - EjA~85°!!!).

You forgot to set the TIn in the surface launch. Also, you may need to fine tune the TEj to prevent 180 degree transfer angle in off-plane transfer mode. Very high EjA is often caused by near 180 degree transfer case.

My question is: Surface Launch program should find the first best possible launch window, but just referred to the best latitude (BLL), or also from the current latitude? In this case, why RInc is much greater with Surface Launch?

Surface launch is supposed to find the best launch opportunity that will occur with-in the next 24hours. If you are willing to wait longer then better launch windows will come like the RIn=0

Also, it seems there was a small difference between IMFD and Align MFD RInc (about 3° in the first example and 2° in the second).

I don't know what you mean but the IMFD may try to anticipate the RIn in a different point of the flight (in the future).

 

[orbekler]

Thank you very much, Jarmonik, I'm going to follow your suggestions.