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Satellites in Daily Life

Satellites: Present in Everyday Life!

Satellites play a key role in our daily life. We are able to forecast weather thanks to the deployment of satellite systems whose objective is data collection and processing. When reaching a place in a map, navigation satellite system at about 20.000 km far away is the responsible to pinpoint our location at the smartphone’s screen. What’s more, the map image this is displaying has been collected and processed by imagery satellites hundreds of km above Earth’s surface. Weather forecasting, communication, navigation, imagery, these are just some of the satellite applications that exist and that we use daily.

Undoubtedly satellites are one of the best engineering invents ever made. We all know what a satellite is, but if a more sophisticated definition is what you want, NASA dictionary we must ask (Oxford or Cambridge dictionaries are also valid, by the way): “A satellite is a moon, planet or machine that orbits a planet or star.”

So yes, we live on a satellite orbiting the Sun. In fact, it is more common to link the term satellite to natural and artificial objects orbiting planets. An example of a natural satellite that we all must have present at this time of the story is the Moon, while artificial satellites are mostly used when we talk about human-made satellites: a machine that moves around Earth or any other celestial body when it is launched into space.

Satellites orbit Earth at different distances from it, but correctly speaking we must say altitudes. While planes take off, satellites are launched, and therefore once placed into their orbit we say satellite orbits Earth at some altitude, while planes fly at certain altitude. Remember that orbiting is possible thanks to gravity force, this means that the same than an apple apparently fell onto Newton’s head, satellite will also tend to go towards Earth’s centre, therefore, they are falling towards the Earth, but don’t worry, satellite orbit corrections and monitoring are common tasks for space agencies.

Do all satellites orbit at the same altitude?

Shortly answering no, but it is more interesting to know that different orbits can be designed, for example around the equator, along the meridians to pass over the poles, or with some inclinations, etc. All these combinations are possible (with some restrictions) at any altitude.

Most of the daily-life present satellites are classified into LEO, MEO and GEO orbits.

  • LEO: Low-Earth-Orbit, is the closest orbital range to the Earth, typically at an altitude of 180 – 2000 km from Earth surface. Remember airplanes fly at altitudes bellow 14 km. Examples: Internet and Imaging satellites, International Space Station, among others.
  • MEO: Medium-Earth-Orbit, as its name indicates it is in between the closest and furthest orbital range, at an altitude of 2000 – 35.780 km. Examples: Satellite Navigation Systems (GNSS)
  • GEO: Geostationary orbit, is the furthest orbit with respect to Earth’s surface at an altitude about 36.000 km. Examples: Television Satellites.

On image above it is seen how the lowest the altitude of the satellite, the less it takes to complete a full orbit around the Earth, what is called a period. This is due to gravity force, which is stronger with proximity from the Earth’s surface leading to faster orbiting velocities. As a result, ISS (LEO) takes about 90 minutes to complete a full orbit, while GPS satellites (MEO) takes half a day and GEO satellites takes a complete day, which means that are “fixed” on the sky from our perspective.

Now that we have discussed what are satellites and where are they located, the next question that arises is

Which kind of benefits do we get from satellites in daily life?

As previously mentioned, satellites are a key part of almost any system nowadays involving telecommunication.

Maybe the easiest example is that when opening a GPS-based app, this requests our location, which is previously calculated by our smartphone. In this case, satellite navigation is involved through GNSS satellites sending signals continuously towards Earth. This position estimation process is friendly detailed in this post.

However, there are more daily applications that are satellite-dependant:

Thank you for reading!


REFERENCES

Canadian Space Agency. Satellites in our everyday lives. Retrieved from: https://www.nasa.gov/feature/goddard/2020/goldilocks-stars-are-best-places-to-look-for-life
ESA. Types of Orbits. Retrieved from: https://www.esa.int/Enabling_Support/Space_Transportation/Types_of_orbits
NASA. Catalog of Earth Satellite Orbits. Retrieved from: https://earthobservatory.nasa.gov/features/OrbitsCatalog
Union of Concerned Scientists USA. What Are Satellites Used For? Retrieved from: https://www.ucsusa.org/resources/what-are-satellites-used
PCMAG. Why Satellite Internet Is the New Space Race. Retrieved from: https://www.pcmag.com/news/why-satellite-internet-is-the-new-space-race
SPACE.COM. First Responders in Space: How Satellites Save Lives During Natural Disasters. Retrieved from:
https://www.space.com/43202-earth-satellites-save-lives-natural-disasters.html