  We introduce an algebraic system which can be used as a model for spaces with
geodesic paths between any two of their points. This new algebraic structure is
based on the notion of mobility algebra which has recently been introduced as a
model for the unit interval of real numbers. We show that there is a strong
connection between modules over a ring and affine mobility spaces over a
mobility algebra. However, geodesics in general fail to be affine thus giving
rise to the new algebraic structure of mobility space. We show that the so
called formula for spherical linear interpolation, which gives geodesics on the
n-sphere, is an example of a mobility space over the unit interval mobility
algebra.
