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Old 02-13-2017, 11:44 AM   #1
GodAtum
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Default Automatic finding of values?

I'm not a programmer, but instead of finding the dv values manually to make the closest approach, surely this is the perfect task for a computer? A computer can just loop trough all the values?
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Old 02-13-2017, 11:47 AM   #2
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Originally Posted by GodAtum View Post
 I'm not a programmer, but instead of finding the dv values manually to make the closest approach, surely this is the perfect task for a computer? A computer can just loop trough all the values?
There are alternative MFDs that solve this problem by differential equations, for example IMFD.

But in general, all approaches to solve this require you to give it good constraints and starting values. You could also take a look at the NASA tool GMAT, though its true power requires Matlab to be installed.
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Old 02-13-2017, 01:16 PM   #3
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 There are alternative MFDs that solve this problem by differential equations, for example IMFD.

But in general, all approaches to solve this require you to give it good constraints and starting values.
Ditto.
My version of TransX does this automatically, but never in manoeuvre mode, since it's very hard to constraint the search space to get reasonable values. For instance: when in Earth orbit, targeting the Moon, without good constraints the best solution is the one, that overshoots the Moon, still having the smallest "Cl. Approach".
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Old 02-13-2017, 01:29 PM   #4
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 For instance: when in Earth orbit, targeting the Moon, without good constraints the best solution is the one, that overshoots the Moon, still having the smallest "Cl. Approach".
Sounds like the astrodynamics version of the old joke "how does an assembler programmer choose to get down a high cliff? GERONIMO!"
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Old 02-13-2017, 02:34 PM   #5
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Ah i see! I've tried using some matlab addons but they enver seemed to get values I could use in orbiter.

Last edited by GodAtum; 02-13-2017 at 02:44 PM.
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Old 02-13-2017, 03:30 PM   #6
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 Ah i see! I've tried using some matlab addons but they enver seemed to get values I could use in orbiter.
Orbiter uses a left-handed coordinate system, while most other software uses right handed coordinate systems. You need to do a projection there.
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Old 02-13-2017, 03:43 PM   #7
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 Orbiter uses a left-handed coordinate system, while most other software uses right handed coordinate systems. You need to do a projection there.
Even this one? http://orbiter-forum.com/showthread.php?t=19682
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