Suppose we want to place a weather satellite into a circular orbit 300 km above the earth's surface. What speed, period, and radial acceleration must it have? The earth's radius is 6380km=6.38×106m, and its mass is 5.98×1024kg. Find the orbit radius for an earth satellite that has a period of 2.5 day (216000 s ). Find the speed for an earth satellite that has a period of 2.5 day (216000 s ).