John Glenn became the first American to orbit Earth in 1962.
Did you know the force of gravity is almost as strong in low Earth orbit as on the surface? So why do astronauts feel weightless?
|Amount of Gunpowder||What Happens|
|2 bags of gunpowder:||Cannonball goes faster and gets farther before gravity pulls it back to Earth.|
|3 bags of gunpowder:||Cannonball is going so fast that it falls all the way around the world. It is in orbit!|
|4 bags of gunpowder:||Cannonball orbits Earth again, but goes even higher at the peak of its arc.|
|5 bags of gunpowder:||Cannonball is going so fast it completely escapes Earth's gravity and heads out into space, maybe to an asteroid or Mars or Jupiter!|
The same thing happens when the Space Shuttle or a satellite is launched into orbit. The rocket boosts the spacecraft up to the height of a "very tall mountain" and also gives the spacecraft its forward speed, like the gunpowder gives the cannonball. So the spacecraft just falls all the way around the Earth, never hitting the surface. The curve of the spacecraft's path is about the same as the curve of Earth's surface.
So astronauts orbiting Earth aren't really weightless, they are just falling . . . and falling, and falling!
How orbits work depends on basic laws of physics, as Newton described them.