With all the media frenzy about Spacex over the days we received a few requests asking us to explain how satellites are launched into orbit.

We shall do so through a thought experiment proposed by Isaac Newton when he was trying to understand how the moon was orbiting the earth.

## Newton’s cannonball

Just imagine standing on top of a really tall mountain with some cannonballs and barrel.

We will start firing these cannon balls with different speeds by constantly increasing the amount of firepowder that we add and observing the response.

**(a) Speed of cannonball < 7300 m/s **

**(b) Speed of cannonball ~7300 m/s —-> Circular orbit**

**( c) Speed of cannonball ~8000 m/s —-> Elliptical orbit**

**(d) Speed of cannonball ~11200 m/s —-> Parabolic trajectory**

**(e) Speed of cannonball – Crazy**

## Gunpowders are not that powerful !

In the real world instead of using gun powder, we use much more sophisticated and powerful

solid rocket fuels which will take the satellite from earth and put it

in orbit.

But once the satellite once put in orbit just keeps falling into orbit.

This applies to the ISS as well: “ISS is always falling; Falling into orbit.**”**

Although this is not by any means a comprehensive post on this topic, but hopefully this gives you a sense of the physics that underlies it.

Have a good one!