[betzaleldaniel]

According to wikipedia :The International Space Station is in a LEO (low Earth Orbit)that varies from 319.6 km (199 mi) to 346.9 km (216 mi) above the Earth's surface.[3]

While a majority of artificial satellites are placed in LEO, where they travel at about 27,400 km/h (8 km/s), making one complete revolution around the Earth in about 90 minutes, many communication satellites require geostationary orbits, and move at the same angular velocity as the Earth.

Does it mean that the Astronauts that work repairing the space station are traveling that fast?
I assume then that its not harmful to travel that fast... it would be possible for a human to travel at speed of light?

[ebaines]

Astronauts on the International Space Station are indeed traveling at about 27.400 Km/h, relative to the earth's surface. Remember that all velocities are measured relative to something else, which is assumed to be "stationary" even though it may be moving relative to something else. For example, as you read this you are sitting on the earth's surface, which is rotating at 1650 Km/h relative to the center of the earth, and the earth is moving at about 100,000 Km/h as it orbits the sun. So you yourself are traveling at over 100,000 km/h right now, with no ill effects.

But this does not mean that you can travel at the speed of light, c. The issue isn't whether it causes "harm" to a human, but rather that relativistic effects set in as your speed approaches c, which has the effect of increasing an object's mass as measured by an observer in a resting frame of reference. As your speed approaches c your mass increases to infinity. Thus it takes an infinite amount of energy to accelerate an object to c. Hence it is impossible for any object with mass to move at the speed of light.