Question

what is meant by perigee?

Answer 1

When a satellite follows a non-circular orbit around the earth, the satellite's path is an ellipse with the center of the earth at one focus. Such a satellite has variable altitude and variable orbital speed. The point of lowest altitude is called perigee. The term also applies to the minimum distance in kilometers or miles between the satellite and the center of the earth. (Perigee can be measured between the satellite and the earth's surface, although this is a less precise specification because the earth is not a perfect sphere. The difference is approximately 4,000 miles or 6,400 kilometers.)