how would eath's gravity effect you in space??? At what altitude does the Earth's gravity no longer have an effect on the astronauts or the space shuttle???

The force of earth's gravity on you is proportional to 1/distance^2

Therefore it never,ever, goes away. It just gets smaller and smaller.
If you go 1 earth radius up, you will be twice as far from earth center as you are here and it will be mg/4

If you get 5 earth radii from earth center it will be mg/25

10 radii is mg/100

100 radii is mg/10,000

What really matters is what happens when you get near something else massive, like Mars. Then the force of Mars gravity would be millions of times the tiny remaining earth gravity and you could do all your Mars landing computations ignoring earth gravity.