Have you ever wondered why most rockets and spacecraft are launched towards the east? Is it just a coincidence, or is there a scientific reason behind it? The answer lies in one of Earth's fundamental properties—its rotation. 

The Science Behind Eastern Launches 

To stay in orbit, a spacecraft must travel at a speed of around 28,200 km/h (17,500 mph). Achieving such high speeds requires an immense amount of fuel and energy. However, engineers have found a clever way to make this process more efficient—by leveraging Earth's rotation. 

The Earth spins from west to east at different speeds depending on the latitude. Near the equator, this rotational speed is about 1,600 km/h (1,000 mph). When a spacecraft is launched in the same direction as Earth's rotation (eastward), it gains an extra velocity boost from the planet’s motion. This allows rockets to use less fuel to reach the required orbital velocity. 

The Cost of Launching Westward 

If a rocket were to launch westward, it would have to overcome Earth's rotational speed first before accelerating to the required orbital velocity. This would mean burning significantly more fuel, making the launch inefficient and expensive. That’s why space agencies like NASA, ISRO, and SpaceX prefer launching towards the east whenever possible. 

Are There Exceptions? 

Yes! Not all launches go eastward. There is one key exception—polar orbits. Spacecraft destined for a polar orbit (used for Earth observation and reconnaissance satellites) are launched north or south instead. Since these orbits cover the entire planet, leveraging Earth's rotation is not necessary. 

How Different Space Agencies Use This Advantage 

Many space agencies choose launch sites close to the equator to maximize the rotational speed benefit. 

For example: 

• Kennedy Space Centre (USA) at 28.5°N 

• Guiana Space Centre (Europe) at 5°N 

• Satish Dhawan Space Centre (India) at 13.7°N 

These locations ensure that rockets gain as much advantage as possible from Earth's rotation. 

Next Time You Watch a Rocket Launch… 

Remember, every launch is a well-planned event that considers the Earth’s rotation to optimize fuel efficiency. The direction of launch is not just a random choice—it’s a carefully calculated maneuver that saves costs, increases payload capacity, and enhances mission success.