LEO (Low Earth Orbit): Advantages and Disadvantages

This page explores the advantages and disadvantages of Low Earth Orbit (LEO). It highlights the pros and cons of using LEO for satellite applications.

LEO stands for Low Earth Orbit. LEO, MEO (Medium Earth Orbit), and GEO (Geostationary Earth Orbit) are the three main types of orbits, categorized by their distance from Earth, ranging from the closest (LEO) to the farthest (GEO).

Satellites are placed in these orbits after their launch.

Here are some key features of LEO orbits:

• Orbit period: 10 to 40 minutes
• Orbit height from Earth: 500 to 1500 km
• Satellite lifespan: Short
• Propagation loss: Least
• Number of satellites needed for global coverage: 40 to 80

Figure 1: LEO (Low Earth Orbit). For more information, refer to LEO vs MEO vs GEO and satellite basics.

Advantages of LEO Orbit

Here are the benefits of using LEO:

• Better Signal Strength: Being closer to Earth allows LEO satellites to provide stronger signals. This means less power (around 1 watt) is needed for transmission.

• Low Latency: LEO has the lowest propagation delay (around 10ms) compared to other orbits due to its proximity to Earth. This lower latency makes it suitable for real-time, time-critical applications.

• Simpler Receiver Equipment: Higher Carrier-to-Noise (C/N) ratios mean that bulky receiver equipment isn’t needed.

• Affordable Ground Stations: Ground stations can utilize more cost-effective satellite equipment.

• Frequency Reuse: Smaller footprints allow for better frequency reuse.

• Polar Region Coverage: LEO provides better elevation for polar regions, leading to improved global coverage.

Disadvantages of LEO Orbit

Here are the drawbacks of using LEO:

• Limited Coverage Area: Due to its lower altitude, each LEO satellite covers a smaller area on Earth. This necessitates a large number of satellites to provide comprehensive global coverage, increasing the overall system cost.

• Frequent Handover: LEO satellites are constantly moving. Service must be handed off from one satellite to the next in the constellation. A succession of satellites is needed to cover any given region on Earth.

• Atmospheric Effects: Atmospheric effects are more pronounced at LEO altitudes. This can cause gradual orbital dis-orientation of the satellites, requiring regular maintenance to keep them on track.

• Short Visibility Window: A LEO satellite is only visible for about 15 to 20 minutes from a particular area on Earth. This short window limits the time available for testing and troubleshooting.

• Lower Efficiency in Populated Areas: Serving densely populated regions is less efficient compared to GEO satellites.

• Complex Ground Stations: Ground stations must handle frequent handoffs between LEO satellites, adding to their complexity.

• Time to Deployment: The entire LEO constellation needs to be deployed before service can begin. This leads to a longer time to market and user adoption compared to GEO satellites.

• Shorter Lifespan: LEO satellites typically have a shorter lifespan (around 5 to 8 years) compared to GEO satellites (around 10 years).