Low Earth Orbit

Definition

Low Earth Orbit (LEO) refers to an orbit around the Earth at altitudes between approximately 160 kilometers (100 miles) and 2,000 kilometers (1,200 miles). This region is crucial for various applications, including satellite deployment, space stations, and scientific research, making it an important focus in mission design and orbital considerations.

5 Must Know Facts For Your Next Test

1. Satellites in low earth orbit travel at speeds of about 28,000 kilometers per hour (17,500 miles per hour), allowing them to complete an orbit around the Earth approximately every 90 minutes.
2. LEO is commonly used for Earth observation satellites, communication satellites, and crewed space missions like the International Space Station (ISS).
3. The lower altitude of LEO allows for reduced latency in communication and higher resolution imaging compared to satellites in higher orbits.
4. Due to proximity to the Earth's atmosphere, LEO satellites experience more atmospheric drag, which can affect their operational lifespan and require periodic adjustments.
5. Low Earth Orbit is becoming increasingly crowded with thousands of satellites launched for various purposes, raising concerns about space debris and collision risks.

Review Questions

• How does the altitude of low earth orbit impact satellite operations compared to higher orbits?
  • Low Earth Orbit provides several advantages for satellite operations compared to higher orbits. Satellites in LEO experience lower latency in communication due to their closer proximity to Earth. This results in faster data transmission for applications such as remote sensing and real-time communications. Additionally, LEO allows for higher-resolution imaging because satellites can capture finer details from lower altitudes, making it ideal for Earth observation missions.
• Discuss the challenges associated with maintaining satellites in low earth orbit, especially regarding atmospheric drag.
  • Maintaining satellites in low earth orbit presents unique challenges due to atmospheric drag. As these satellites are closer to the Earth's atmosphere, they encounter resistance that gradually slows them down and lowers their altitude. To counteract this effect, operators must regularly perform orbital maneuvers using onboard thrusters to maintain their designated orbits. This increases operational costs and requires careful planning to ensure that satellites remain functional over their intended lifespan.
• Evaluate the implications of increasing satellite congestion in low earth orbit on future space missions and potential regulations.
  • The rising number of satellites in low earth orbit leads to significant implications for future space missions and necessitates potential regulatory measures. The increasing congestion raises concerns about collision risks and space debris generation, which can jeopardize both operational satellites and crewed missions like those to the ISS. As more entities plan to launch satellites for communication and Earth observation, establishing clear guidelines and regulations becomes essential to ensure sustainable use of LEO. This includes managing frequency allocations and developing tracking systems to mitigate collision risks while promoting cooperation among nations and private companies.

Related terms

Geostationary Orbit: An orbit that allows satellites to remain in a fixed position relative to the Earth's surface, located approximately 35,786 kilometers (22,236 miles) above the equator.

Orbital Inclination: The angle between the orbital plane of a satellite and the equatorial plane of the Earth, affecting coverage area and operational capabilities.

Launch Window: A specific time period during which a spacecraft can be launched to reach its intended orbit, influenced by factors such as planetary alignment and mission requirements.