Suppose we have a satellite in an elliptical orbit around the Earth with the major axis pointed towards some fixed point in the heavens. What is the minimum number of rocket burns so that the major axis is rotated 90 degrees and the final and initial energy are the same. Is the number 2? At closest approach to the Earth, slow down, one burn, orbit circular, 90 degrees later speed back up, one more burn or at farthest approach speed up, 90 degrees later slow down, again two burns? Thanks for any help!