Orbital Mechanics: The Science Behind Satellite Movement and Control

Orbital mechanics, also known as astrodynamics, is the field of study that explains how objects move in space under the influence of gravitational forces. It forms the foundation for understanding how satellites are launched, maneuvered, and maintained in orbit. Mastering orbital mechanics is essential for successful satellite missions, as it allows precise control of satellite trajectories to ensure they remain in their designated orbits, whether for communication, weather monitoring, or scientific research.

This article explores the principles governing satellite motion, the forces involved, and how these concepts are applied to manage satellites in orbit.

What Is Orbital Mechanics?

Orbital mechanics refers to the science that deals with the motion of objects in space, primarily under the influence of gravity. In the context of satellites, it addresses how these man-made objects move around the Earth or other celestial bodies, guided by specific laws of physics such as Newton’s Law of Universal Gravitation and his Three Laws of Motion.

Newton's insights into how objects interact with gravitational forces are the foundation of orbital mechanics. Specifically, the force of attraction between two masses, like a satellite and the Earth, determines the satellite's trajectory and speed in orbit.

The Basics of Satellite Orbits

When a satellite is launched into space, it is propelled into a particular orbit depending on its speed and altitude. The key factors that define a satellite's orbit are:

Once in orbit, satellites follow elliptical paths around the Earth, as described by Kepler's Laws of Planetary Motion, which apply to any orbiting body, including moons and planets.

Kepler’s Laws of Planetary Motion

Johannes Kepler developed three fundamental laws that describe the movement of objects in orbit:

These laws are critical for calculating satellite orbits, predicting their position, and adjusting their paths for long-term missions.

Types of Satellite Orbits

Satellites can be placed in various orbits, depending on their purpose and mission objectives. The most common types include:

Forces Influencing Satellite Motion

Satellites in orbit are subject to several forces, the most significant being gravity. In addition to gravity, the following forces affect a satellite’s motion:

Orbital Maneuvering and Control

Controlling a satellite’s position and velocity in orbit is crucial for maintaining its functionality. To achieve this, satellites are equipped with thrusters or propulsion systems that allow for orbital adjustments. These maneuvers are necessary for various reasons, including:

Conclusion

Orbital mechanics is a fundamental science that governs how satellites move and function in space. From the moment a satellite is launched to the end of its mission, understanding these principles ensures the satellite can be controlled, maneuvered, and maintained for optimal performance. The application of Newton’s Laws, Kepler’s Laws, and other principles of motion and gravity allows satellites to serve their essential roles in communication, navigation, Earth observation, and scientific discovery.

As satellite technology continues to advance, the precise knowledge of orbital mechanics remains at the heart of successful space missions, allowing us to explore the vastness of space while making life on Earth more connected and informed.

Recommended products for building a satellite

If you're planning to build a satellite at home, here are some top products you can purchase online to get started with a small satellite project, like a CubeSat:

These products, along with open-source satellite kits, can give you a solid foundation to design and assemble a small satellite for educational or hobbyist purposes!

Building a fully functional satellite using the listed products is an exciting and complex project. Here's a step-by-step guide to help you assemble these components into a working satellite, such as a CubeSat:

Step 1: Define Your Satellite’s Mission

Before assembly, decide what your satellite will do. Whether it’s Earth observation, communication, or scientific experiments, defining the mission will help you choose the right sensors and equipment.

Step 2: Build the CubeSat Frame


Step 3: Design the Power System


Step 4: Set Up the Onboard Computer


Step 5: Attach Sensors and Modules


Step 6: Communication System


Step 7: Write and Upload the Software


Step 8: Testing and Simulation


Step 9: Launch Preparation


Step 10: Launch and Operate

Building a satellite at home is an ambitious yet achievable goal for hobbyists, engineers, and students. With these components, proper planning, and the right mission objectives, you can contribute to space research and innovation right from your home.