Satellite Motion Satellite – an object that’s in orbit about the Earth because it is actually stuck in projectile motion! they’re in free fall toward the Earth while they have an incredible vh = 8 km/s (18,000 mph) where the combination of these acting together produce a trajectory path whose curve exactly matches the curvature of the Earth! Ex: moon space shuttles & ISS communication satellites

Satellite Motion In pictures, of people in these situations, they’re always floating, as if they’re weightless. So does that mean there’s no gravity present to affect them? NO!! Gravity is there – let’s think about that…

What holds the moon to Earth? Gravity, and by our classroom globe’s scale, the moon would be positioned about 30 ft from its surface. Now, where do these satellites hang out? Anywhere between 100 to 500 miles above the surface of the earth, but on the scale of our globe, that’s less than 1/2 inch off its surface!! Gravity is not only present, it’s barely diminished from what we’ve got on the surface of earth!! So then why are they floating??

Actually the astronauts are not floating, they‘re falling – It’s just that everything around them is falling too, which isn’t much anyway – no buildings, trees etc to be passing by “on your way down” And they’re not worried about hitting the ground, since they never get any closer to it, thanks to that huge vh: “they fall around the Earth rather than into it” And they don’t even take notice of their huge vh, since All of the objects around them – space shuttle, ISS, satellite they’re working on – move right with them. So even when they take a “space walk”, they continue along side the vehicle! Plus, there’s no air or wind to indicate motion