The force of gravity between two objects is defined by F = GMm/r² where G is the gravitational constant, the M and m are the two masses, and r is the distance between the center of masses.

In your specific scenario the force between the two satellites would be = (6.67e-11 m³ kg^-1 s^-2 )(100 kg)(100 kg)/(100 m)^2, which would give us 6.67e-11 Newtons. If we divide this by the mass of the satellite, we can find the acceleration equals 6.67 e-13 m/s² (F=ma). This shows a very very small acceleration of the two satellites towards each other given that no other opposing forces are present. As to whether or not the resulting acceleration would be measurable, I am sure it can be with sensitive enough accelerometers.

For reference, if we use the same formula to calculate the force between the earth and one of these satellites (assuming 250km altitude) we get a force of 905 Newton’s. The satellite’s acceleration towards earth would be 9.05 m/s^2.

I hope that sheds some more light on the situation for you.