Supersymmetric vacuum configurations in string cosmology - art. no. 043507.

We examine in a cosmological context the conditions for unbroken supersymme try in N=1 supergravity in D=10 dimensions. We show that the cosmological s olutions of the equations of motion obtained considering only the bosonic s ector correspond to vacuum states with spontaneous supersymmetry breaking. With a nonvanishing gravitino-dilatino condensate we find a solution of the equations of motion that satisfies necessary conditions for unbroken super symmetry and that smoothly interpolates between Minkowski space and de Sitt er space with a linearly growing dilaton, thus providing a possible example of a supersymmetric and nonsingular pre-big-bang cosmology. [S0556-2821(99 )01402-2].