How do Satellites work? | ICT #10

Summary

This video provides an insightful overview of satellite technology, explaining the different types of orbits—Low Earth Orbit (LEO), Medium Earth Orbit (MEO), and Geosynchronous Earth Orbit (GEO)—and the specific applications suited for each. It highlights satellite components such as transponders, solar panels, and thrusters, which ensure satellites function efficiently. Additionally, the video touches on satellite health monitoring, their protection against extreme space conditions, and the management of satellites at the end of their life cycle, including their transfer to graveyard orbits. A must-watch for understanding how satellites impact communication, navigation, and Earth observation.

Takeaways

• 😀 Satellites orbiting Earth serve a wide range of purposes, including communication, GPS, and Earth observation, with nearly 4900 satellites currently in orbit.
• 😀 Satellites stay in orbit due to the balance between gravitational pull and centrifugal force, which is maintained through their speed.
• 😀 Satellites in Low Earth Orbit (LEO) are closest to Earth and are used for tasks like weather observation and communications, but require multiple satellites for global coverage.
• 😀 Geosynchronous Earth Orbit (GEO) satellites, positioned at 35,786 km, rotate at the same speed as Earth, making them ideal for TV broadcasting as they remain fixed relative to the Earth’s surface.
• 😀 The Geostationary Orbit, a subset of GEO, allows satellites to stay stationary over the same point on Earth, useful for broadcasting without needing constant dish adjustment.
• 😀 Medium Earth Orbit (MEO) is used by GPS satellites because of its optimal balance between coverage and accuracy, with 24 MEO satellites enough to cover the entire Earth.
• 😀 Transponders are the core components of communication satellites, converting frequencies, removing signal noise, and amplifying signals to ensure clear communication.
• 😀 Solar panels and batteries power satellites, with solar panels providing energy and batteries taking over when satellites are in Earth’s shadow during an eclipse.
• 😀 Thrusters are used to adjust and maintain the satellite's position in orbit, helping to avoid displacement due to irregular gravitational forces and space debris.
• 😀 Inactive satellites are moved to a ‘graveyard orbit’ above the geostationary orbit at the end of their lifespan to prevent interference with operational satellites.
• 😀 Satellites are covered with multi-layered insulation to protect them from extreme temperature variations and solar radiation, ensuring the safety of their components.

Q & A

Why do satellites remain in orbit around Earth?

Satellites remain in orbit due to the balance between gravitational pull and centrifugal force. The angular velocity of a satellite is determined by the force balance equation, which ensures it stays in motion without needing external energy.

How does a satellite maintain its speed in orbit?

Satellites maintain their speed because there is negligible resistance in space, allowing them to continue their circular motion indefinitely without external energy sources.

What are the main types of orbits for satellites?

The main types of orbits are Low Earth Orbit (LEO), Medium Earth Orbit (MEO), and Geosynchronous Earth Orbit (GEO). These orbits vary in altitude and function depending on the satellite's purpose.

Why is the Van Allen belt avoided for satellite placement?

The Van Allen belt contains highly energetic charged particles, which can damage the electronics of satellites. Therefore, it is generally preferred not to place satellites within this region.

What is the role of geostationary satellites in broadcasting?

Geostationary satellites remain stationary with respect to Earth, making them ideal for television broadcasting since they eliminate the need for constant adjustment of satellite dishes.

How does the orbital altitude affect satellite coverage?

Satellites in higher orbits, like GEO, can cover a larger area of Earth. For example, three satellites in GEO can cover one-third of the Earth's surface, whereas satellites in LEO cover smaller areas.

Why are more satellites needed for LEO compared to GEO?

Satellites in LEO cover less area and revolve at high speeds, requiring more satellites to provide global coverage. In contrast, GEO satellites can cover larger areas and require fewer satellites.

What is the function of a transponder in a communication satellite?

The transponder in a satellite changes the frequency of the received signal, removes noise, and amplifies the signal power to ensure clear communication.

How do satellites remain in their intended orbital position?

Satellites use thrusters to adjust their position when displaced from their intended orbit. These thrusters are fired to correct the satellite’s trajectory and avoid losing signal.

What happens to a satellite when its mission is over or its lifespan ends?

Inactive satellites are moved to a 'graveyard orbit,' a higher orbit above the geostationary orbit, to prevent them from interfering with operational satellites.