Orbital motion of satellites: Space physics: Physics: GCSE (9:1)

Gravity

The force needed to maintain a stable orbit of planets around a star and satellites around a planet

Orbit

The circular path that an object follows as moves around another body in space

Satellite

Any object that orbits a planet

Natural satellite

A natural object that orbits a planet e.g. the Moon

Artificial satellite

An artificial object that orbits a planet e.g. communication satellites

Stable orbit of a satellite

When the speed of a satellite is slow enough to stop it flying off into space, but fast enough to stop it falling back towards the planet

Problem when a satellite is travelling too quickly

The gravitational attraction between the Earth and the satellite is too weak so the satellite will fly off into space

Problem when a satellite is travelling too slowly

The gravitational attraction between the Earth and the satellite will be too strong so the satellite will fall towards the Earth

Speed at which a satellite will fly off into space

Above 11,200 m/s

Speed at which a satellite will fall towards the Earth

Below 7600 m/s

Geostationary satellite

A satellite that orbits the Earth at the same rate as the Earth rotates

How long it takes for a geostationary satellite to orbit the Earth

24 hours

Position of a geostationary satellite relative to the Earth's surface

It remains above the same place on the Earth's surface