Uses of Satellites (SQA National 5 Physics): Revision Note

Uses of satellites

• Artificial satellites have benefited society for several decades, including:

  • global positioning systems (GPS)

  • weather forecasting

  • communications

  • scientific discovery

  • space exploration

Global positioning systems (GPS)

• Purpose: To determine a precise location anywhere on Earth

• How it works:

  • At least 3 satellites send signals to a receiver (e.g. phone, car)

  • The receiver measures the time delay of signals to calculate its distance from each satellite

  • The overlapping distances (triangulation) pinpoint your exact position

• Orbit type:

  • Medium Earth orbit (~20,000 km)

• Used for:

  • navigation (cars, planes, ships)

  • mapping and surveying

  • tracking wildlife, vehicles, and aircraft

Weather forecasting satellites

• Purpose: To predict the weather and monitor environmental conditions

• Types of orbit:

  • Geostationary satellites continuously monitor one area (useful for mapping cloud movement)

  • Low (polar) orbiting satellites scan the whole Earth as it rotates beneath them

• Also used for:

  • predicting severe weather (storms, hurricanes)

  • observing human impact on the climate and environment

Communications satellites

• Purpose: To transmit information (radio, TV, internet, phone) between locations across Earth

• Orbit type:

  • Usually geostationary, so the satellite stays fixed relative to one area

• How it works:

  • Ground station sends a signal (uplink) to the satellite

  • The satellite amplifies and rebroadcasts the signal (downlink) to another ground station

• Used for:

  • TV broadcasting

  • Satellite internet and phone connections in remote regions

  • Global communications networks

Scientific discoveries and space exploration

• Purpose: To observe distant objects and analyse them to increase our knowledge of the universe

• Examples:

  • Hubble Space Telescope (HST)

  • International Space Station (ISS)

• Orbit type:

  • Both the HST and ISS orbit the Earth every 90 minutes in low Earth orbits

• Benefits of space-based telescopes:

  • No light pollution

  • No distortion from the atmosphere

  • They are not affected by the weather

  • They can be used during the day

  • They can detect radiation from different parts of the electromagnetic spectrum