Satellites are used for various purposes, ranging from communication and navigation to
monitoring and collecting data. Most satellites used for scientific purposes have a low
Earth orbit. Low Earth orbit is 160 to 2,000 kilometers above Earth's surface, just at the
top of the atmosphere. The distance between Earth and the satellite determines the
velocity of the orbit, as well as the gravitational force that is acting on the satellite. For
example, a satellite that provides information to Global Positioning Systems (GPS)
traveling at an altitude of 26,560 kilometers will take 12 hours to complete one orbit
around Earth. A satellite traveling at a low Earth orbit of 705-kilometer altitude can
travel at 27,500 kilometers per hour.
Scientists and engineers use rockets to place satellites into orbit. Satellites can have
circular orbits or elliptical orbits. In a circular orbit, the satellite travels at a constant
speed and the satellite stays the same distance from the center of Earth.
In an elliptical orbit, a satellite travels in a path that is not a uniform distance from
Earth's surface. At points where the satellite is closest to Earth's surface, the satellite will
experience a greater gravitational pull from Earth. In an elliptical orbit, the satellite's
velocity will increase as its height from Earth's surface decreases. The satellite's velocity
will decrease as it moves in the orbit pathway farthest from the surface of Earth. What
does a change in velocity indicate about the forces acting on the satellite?

Satellites in low Earth orbit are constantly being affected by gravity, atmospheric drag,
and solar activity and will come down to Earth unless their orbits are adjusted. Satellites
can also interact with other particles in low Earth orbit. More than 500,000 pieces of
debris are orbiting Earth.
When this occurs, the satellite slows down and is overcome by the force of gravity,
which pulls the satellite toward Earth. In most cases, as the satellite falls out of orbit, it
will burn up in the atmosphere. In September 2011, a decommissioned NASA satellite
fell back to Earth. The satellite broke apart upon entering the atmosphere and NASA
estimates that 26 parts could have survived and landed in a remote location. NASA was
unable to recover any remaining parts of the satellite.

Based on what you read, design a model showing the motion of a satellite. Include labels that the mathematical data represented in the text. Draw and upload your model.