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MontBlanc2012 MontBlanc2012 is offline
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Default Low energy Earth-Moon transfer
by MontBlanc2012 11-23-2017, 04:01 AM

This challenge is a similar transfer to an earlier "Low energy Moon-Earth transfer" challenge.

The scenario starts with DeltaGlider in a standard 300 x 300 km Low Earth Orbit. It has 3475 m/s of main and RCS fuel. The objective is straightforward: transfer the DeltaGlider to a circular lunar orbit with an orbital altitude of 10,000 km or less.

As with the Moon-Earth challenge, this problem should be impossible using a standard Apollo-style Earth-Moon transfer so, again, some 'outside of the box' thinking is required.

Hint 1: TransX is not likely to be of much use.

Hint 2: You may want to try using Lagrange MFD in conjunction with IMFD. For some reason, Lagrange MFD's integration engine seems a little more stable than IMFD's Map Program for this particular problem - and using it seems to reduce MCC requirements by a large margin.

Here, in text form, is the challenge scenario:

Code:
BEGIN_DESC
This scenario starts with DeltaGlider in a standard 300 x 300 km Low Earth Orbit.  It has 3475 m/s of main and RCS fuel.  The objective is straightforward: transfer the DeltaGlider to a circular lunar orbit with an orbital altitude of 10,000 km or less.
END_DESC

BEGIN_ENVIRONMENT
  System Sol
  Date MJD 51985.7065975741
  Help CurrentState_img
END_ENVIRONMENT

BEGIN_FOCUS
  Ship GL-02
END_FOCUS

BEGIN_CAMERA
  TARGET GL-02
  MODE Cockpit
  FOV 50.00
END_CAMERA

BEGIN_SHIPS
GL-02:DeltaGlider
  STATUS Orbiting Earth
  RPOS -6406292.098 588742.155 -1764949.382
  RVEL 2050.0653 -35.4100 -7452.9995
  AROT 147.185 -38.255 25.794
  VROT 0.0246 -0.2133 -0.0138
  AFCMODE 7
  PRPLEVEL 0:0.076749 1:0.013845
  NAVFREQ 586 466 0 0
  XPDR 0
  HOVERHOLD 0 1 0.0000e+000 0.0000e+000
  AAP 0:0 0:0 0:0
  SKIN BLUE
END
And .zip file is attached for those that want to install the .scn file without resorting to cut & paste.

As with the low energy Moon-Earth transfer, I may provide a sample solution in comments below
Attached Files
File Type: zip Earth to Moon low energy transfer.scn.zip (1.2 KB, 2 views)

Last edited by MontBlanc2012; 11-23-2017 at 01:13 PM.
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Old 11-23-2017, 06:57 AM   #2
MontBlanc2012
Orbinaut
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And here is a link to a sample solution to this challenge:



Best viewed with subtitles on.

Last edited by MontBlanc2012; 11-23-2017 at 07:21 AM.
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Old 11-30-2017, 11:46 AM   #3
BrianJ
thing
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Another fun challenge for Lagrange point fans
This Lunar-flyby-to-Earth/Sun-L1 solution fell out pretty easily. Did you set it up on purpose?

3113m/s ejection burn after 7/8 orbit...
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Just before Lunar flyby, could go to L1 halo orbit from here......
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1st course correction......
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2nd course correction....
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Adjusting the encounter.......
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Setting up the orbit insertion burn....
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In polar orbit, looking down on North Pole......
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Good fun! Cheers,
BrianJ
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Old 12-01-2017, 12:06 PM   #4
MontBlanc2012
Orbinaut
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Quote:
This Lunar-flyby-to-Earth/Sun-L1 solution fell out pretty easily. Did you set it up on purpose?
No, not especially. The solution I found was actually two days in the future.

What this shows, I think is that so long as one isn't aiming for the absolute lowest possible dV requirement, the solution to this problem is quite date tolerant offering a fairly large transfer window.

---------- Post added at 12:06 PM ---------- Previous post was at 11:59 AM ----------

Addendum: having looked at BrianJ's screenshots, I note that he managed to save some fuel by incorporating a lunar flyby and so getting a bit of a gravity assist.

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