>>Gravity Probe B is testing the concept of "frame dragging". As earth travels through space at 70,000 miles per hour, its mass disturbs space which create gravity. Also, as the earth travels through space at 70,000 miles per hour, the earth spins on its axis, so like a ball spinning in water, the water would be disturbed and would be dragged in the direction of the ball's spin. Gravity Probe B is looking for evidence that earths spinning on its axis is dragging space in a circle motion in the direction of earths rotation.
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>When a ball spins on water, there is certain amount of friction between the ball and the surrounding water.
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>I was under the impression that in space there is virtually no friction.
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>Is this a correct assumption?

It is not the friction. It is the mere fact that the mass is rotating. This is not classical physics we are talking about.

The effect, by the way, would be negligible under normal circumstances, and would require extremely precise measurements. This is why they launched Gravity Probe B.

For comparison, a clock goes slower when it moves fast - but unless the speed is close to the speed of light, the difference is very small. (It has been measured, in planes that carried very precise atomic clocks.)