Visible curve - ipo


I’m using Blender to simulate the movement of a satellite around the earth.
I successfully represented the motion of the Earth, the Moon and the satellite with python and ipo curves.

It is quite easy to represent the position of each body at a certain frame with, e.g., such a piece of code:

for i in range(1,l,1): 
  sat_ipo_locX.addBezier ((i,cos((i-1)*2*pi/l)*x-sin((i-1)*2*pi/l)*y))
  sat_ipo_locY.addBezier ((i,sin((i-1)*2*pi/l)*x+cos((i-1)*2*pi/l)*y))
  sat_ipo_locZ.addBezier ((i,z))

My problem is that I would like one of the ipo curves (the one associated to my satellite) to be clearly visible and appear as the satellite follows its orbit.

It needs to be very precise so the ipo curve editor is not so useful for me. Is there any way to do it with python?

Thanks for your help,