As I try to comprehend how spacecraft are able to stay in orbit around the Earth I began to think about why the Earth's own orbit around the Sun does not influence spacecraft in Earth's orbit.
I came to the conclusion that the Earth's gravity holds spacecraft in place and everything in orbit around the Earth also orbits together with the Earth around the Sun, orbiting spacecraft are therefore not influenced by the 30km/s orbital speed of the Earth.
In my naivety I imagined this to be similar to a train journey, the passengers inside the train are not aware of the trains speed. If I go for a walk along the train my velocity is measured relative to other stationary objects in the train, i.e. a few km/h whilst I am in fact travelling at 100km/h+. I am held in place inside the train by the physical boundaries of the coach I am in. If I was to step out of the train whilst it was moving I would then certainly realize it's true velocity and it would speed off into the distance away from me.
In terms of my train analogy this means that the ISS for example is orbiting at 7km/s around the Earth and also orbiting at 30km/s with the Earth around the Sun and the ISS crew and spacecraft (similar to us on Earth) are not aware of the extra velocity?
My thoughts lead to another (possible very naive) question - with the Earth and everything around it moving so fast in its orbit is it possible to travel far enough away from the Earth or the Solar system - to step out of the train so to speak - such that one would observe the Earth speeding away on its 30kms/s orbit?