RSWingman
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How to distill this down:
I'm attempting to retrace the trajectory of Cassini. I've even downloaded a scenario saved in well-organized parts. My greatest trouble comes with the most critical sling of all - the final Venus encounter enroute to Earth.
Setup (using TransX): I've just lost the cruise stage from the DSM and the Venus Encounter stage is now Stage 1 ("cruise to Earth" is 2, "Earth Encounter" is 3, "Cruise to Jupiter" is 4... getting ahead of myself now).
On stage 3 (Earth Encounter), I've got the green line going directly through Earth. This obviously means that stage 2 (cruise) is right on. And in stage 1 (Venus Encounter), I've perfectly matched the dashed yellow line at around Pe-6.5M. Rinc is nearly 0. That's how right-on I am. Aren't I?
I've got my quicksave at this point so that I can keep picking-up from there. But every time, after the sling and right after I lose the Encounter stage, I am revealed to be several G off course (an amount that requires several K of dv correction - way unacceptable). But I was RIGHT ON; this doesn't make sense and it's driving me nuts. :compbash2:
I've seen successful stages (performed by others) where the plane was maybe 30 degrees off and was apparently disregarded; but the coming maneuver worked out fine. This is a contradiction I can't wrap my brain around (though I'm beginning to think that it may have to do with keeping on Earth's plane - I'll be experimenting more with that theory). :hmm:
I know my problem is at least plane related as I've begun to notice upon loading the quicksave (just by eyeballing an imaginary line from Earth, through Venus, to myself, that I am off plane. I'm seeing how Venus is throwing me off plane; and I've been using hover to correct this by eye, pre-sling. My result after losing Encounter is better but not enough and this can't be the right way.
Is my Rinc not supposed to be 0 approaching Venus? How do I determine what approach plane will produce the right release angle to Earth? What procedure am I missing in the approach to Venus? How is the appropriate plane determined in any given situation?
I'm attempting to retrace the trajectory of Cassini. I've even downloaded a scenario saved in well-organized parts. My greatest trouble comes with the most critical sling of all - the final Venus encounter enroute to Earth.
Setup (using TransX): I've just lost the cruise stage from the DSM and the Venus Encounter stage is now Stage 1 ("cruise to Earth" is 2, "Earth Encounter" is 3, "Cruise to Jupiter" is 4... getting ahead of myself now).
On stage 3 (Earth Encounter), I've got the green line going directly through Earth. This obviously means that stage 2 (cruise) is right on. And in stage 1 (Venus Encounter), I've perfectly matched the dashed yellow line at around Pe-6.5M. Rinc is nearly 0. That's how right-on I am. Aren't I?
I've got my quicksave at this point so that I can keep picking-up from there. But every time, after the sling and right after I lose the Encounter stage, I am revealed to be several G off course (an amount that requires several K of dv correction - way unacceptable). But I was RIGHT ON; this doesn't make sense and it's driving me nuts. :compbash2:
I've seen successful stages (performed by others) where the plane was maybe 30 degrees off and was apparently disregarded; but the coming maneuver worked out fine. This is a contradiction I can't wrap my brain around (though I'm beginning to think that it may have to do with keeping on Earth's plane - I'll be experimenting more with that theory). :hmm:
I know my problem is at least plane related as I've begun to notice upon loading the quicksave (just by eyeballing an imaginary line from Earth, through Venus, to myself, that I am off plane. I'm seeing how Venus is throwing me off plane; and I've been using hover to correct this by eye, pre-sling. My result after losing Encounter is better but not enough and this can't be the right way.
Is my Rinc not supposed to be 0 approaching Venus? How do I determine what approach plane will produce the right release angle to Earth? What procedure am I missing in the approach to Venus? How is the appropriate plane determined in any given situation?