Assume that Earth is a sphere with radius R. A satellite has an elliptical orbit with the center of Earth at one focus. The lowest point of the orbit is 5R above the surface of Earth, when the satellite is directly above the North Pole. The highest point of the orbit is 11R above the surface of Earth, when the satellite is directly above the South Pole. What is the height of the satellite above the surface of Earth, when the satellite is directly above the equator?