How do you get into Orbit?                           
•What exactly is weightlessness and what does it have to do with being in “Orbit”? •Lets start by using a thought experiment originally conceived by Newton, which explains both points clearly. Netwon Cannon Example •You can think of it as a continual freefall…what actually keeps objects in orbit is that they are going so fast that they keep falling off the edge of the horizon before it can reach it….this happens perpetually.
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http://www.wired.com/wp-content/uploads/images_blogs/dangerroom/2009/10/312934main_image_1283-9461.jpg
Feb 2009 Assessment of Earth Orbiting
Man-Made Objects
4800 m/s, but start lower and allow crowd to guess for a little while.
Newton’s First Law of motion: Every object will stay in motion till acted upon by an external force.

What exactly does this cannon experiment explain? Firstly, the cannon ball is not exactly weightless in orbit, but in what we call “Microgravity”. There is still a small, but obvious gravitational effect keeping the ball in orbit.

Food for thought: The ISS (International Space Station) for example orbits at an average speed of 17,100 mph. It averages an altitude of 420km to 423km and orbits the entire Earth every 98.87 minutes. Think about that next time you travel by plane somewhere and can’t wait to land.