A satellite in orbit is still being pulled by gravity. Its sideways motion carries it forward while its path curves around Earth. For a suitable initial velocity, the curved path stays above the surface.
Speed changes the trajectory
Imagine starting at the same position each time. Change only the sideways speed. One path intersects Earth, another closes around it, and a sufficiently fast one remains open. Those are the three experiments you can try in our Orbit Lab.
In an ideal circular orbit, the required speed is v = √(μ / r), where r is distance from Earth's centre and μ is Earth's gravitational parameter. Increase r and the circular speed decreases. A different speed at that same position generally produces a different trajectory.
Try it in Orbit Lab →
What the model leaves out
The lab uses a spherical Earth and a satellite with negligible mass. It leaves out air resistance, the Moon, Earth's rotation and variations in its gravity field. Its launch altitude is a starting condition, not a rocket flight from the ground. The picture is an explanation of a model, not a live satellite tracker.
Sources & model notes
Diagrams are explanatory illustrations. EXOVAS is independent and is not affiliated with NASA or JPL.