sentences:  After the successful launch of Sputnik on October 4, 1957, the race was on to calculate and predict where the first man-made satellites would appear in the sky.Fred Lawrence Whipple, then director of the Smithsonian Astrophysical Observatory (SAO) in Cambridge Massachusetts, had gathered amateur astronomers to track artificial satellites in an organization called Operation Moonwatch.The aim was to get the position of the satellite in order to obtain its orbital elements.