Once a rocket reaches space, it can place satellites into orbit. But why don't satellites simply fall back to Earth?
A satellite is constantly falling towards Earth due to gravity. However, it is moving sideways so quickly that it keeps missing the Earth. This creates a continuous orbit around the planet.
Earth's gravity pulls the satellite inward and provides the force needed to keep it moving in a circular path.
The satellite's sideways velocity prevents it from falling directly towards Earth.
The balance between gravity and velocity creates a stable orbit.
Where:
v = orbital speed
G = gravitational constant
M = mass of Earth
r = distance from Earth's centre
Engineers use equations like this to calculate how fast satellites must travel to remain in orbit. If the speed is too low, the satellite falls back to Earth. If it is too high, it may escape Earth's gravitational pull.
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