Can anyone suggest how to calculate the semi major axis of a body in an elliptical orbit when all I've got is x,y,z,vx,vy and vz?(adsbygoogle = window.adsbygoogle || []).push({});

I'm guessing I need to calculate the eccentricity too. I really suck at conversions like this. :(

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# Semi-major axis from cartesian co-ordinates

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