Is there gravity at a space station?

Even though free fall causes objects on the International Space Station to appear to be weightless, there actually is gravity. Gravity gets weaker as you move away from the Earth, although it still exists. The change in gravity can be calculated with the equation: 1/(Radius^2). The Earth is about 4000 miles in radius, so in the equation, 4000 miles would be R=1. At 4000 miles in altitude, the distance to the center of the Earth would be 8000 miles so it would use R=2 (twice the radius of the Earth). At the space station's altitude of 200 miles, the equation would use R=1.05. 1/(1.05^2) equals about .91, so gravity on the space station is about 91% of the gravity on the Earth.