What force of gravity exists at two times the Earth's radius?

Assuming you mean from the center of the Earth: 1/22 = 1/4, that is, 1/4 the gravity at the Earth's surface.

If you mean two Earth radii from the surface, then the distance from the Earth's center would be 3 times as much, and the force would be 1/9, compared to the Earth's surface.

_______________________________

The force of gravity changes with the reciprocal of the square of the distance. So if the distance is increased by a factor of 2, the force will DECREASE by a factor of two squared, or 4.

So, double the distance = one-quarter the force.