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