  Starting from a peculiar orientifold projection proposed long ago by
Angelantonj and Cardella, we elaborate on a novel perturbative scenario that
involves only D-branes, together with the two types of orientifold planes ${\rm
O}_{\pm}$ and anti-orientifold planes $\overline{{\rm O}}_{\pm}$. We elucidate
the microscopic ingredients of such models, connecting them to a novel
realization of brane supersymmetry breaking. Depending on the position of the
D-branes in the internal space, supersymmetry can be broken at the string scale
on branes, or alternatively only at the massive level. The main novelty of this
construction is that it features no NS-NS disk tadpoles, while avoiding
open-string instabilities. The one-loop potential, which depends on the
positions of the D-branes, is minimized for maximally broken, nonlinearly
realized supersymmetry. The orientifold projection and the effective field
theory description reveal a soft breaking of supersymmetry in the closed-string
sector. In such models it is possible to decouple the gravitino mass from the
value of the scalar potential, while avoiding brane instabilities.
