2015IOAA理论短问题第5题-卫星轨道

英文题目

An observer is trying to determine an approximate value of the orbital eccentricity of a man-made satellite. When the satellite was at apogee, it was observed to have moved by $$∆𝜃_{1}$$ = 2′44" in a short time. When the radius vector connecting Earth and the satellite is perpendicular to the major axis (true anomaly is equal to 90o), within the same duration of time, it was observed to have moved by $$∆𝜃_{2}$$ = 21′17". Assume that the observer is located at the center of the Earth. Find an approximate value of the eccentricity of the satellite’s orbit.