Why does a satellite curve?
I think the earth is wobbling on its axis and it makes the tracking lines appear to curve when they are laid over the map.
Satellite dishes are paraboloid in shape - that is, a parabola (a quadratic curve) rotated around its axis. The shape has the property that rays entering it are reflected to its focus of the paraboloid. If the receiver is placed at that point, the signal is picked up from the broadcasting satellite over a wide field of view.
Imagine firing a handgun while standing on earth with no one or thing around for the bullet to hit. The bullet will speed out of the gun, and as it moves it will trace out a curve as it gradually gets pulled to earth by the earth's gravity, and loses speed because of air resistance. It wil then fall to earth perhaps several hundred yards away. Now imagine climbing up a tall tower and doing…
Satellites are used for sending telecommunication and Internet information across the world. It is not possible to run cables everywhere. So the information is sent into space and the satellite sends the information to a satellite dish elsewhere in the world. The signals overshoot the world due to the frequence range used and a satellite artificially augments Earth's curve to send the signals back into Planet Earth.
There isn't any such force. That's why a satellite is constantly falling. But it's also moving "sideways" ... fast enough so that in the time it takes it to fall 1 mile, the surface of the Earth also curves down by 1 mile. So the satellite never gets any closer to the Earth, and continues to fall in a circle that follows the curve of the Earth.
Anything in motion continues moving in a straight line at a constant speed, unless an external force acts on it. That's what would happen to satellites if there were no force to bend their straight-line path into a curve around the Earth. The force is the gravitational attraction between the Earth and the satellite, and it's a 'centripetal' one because it always attracts the satellite toward the 'center' of the Earth.