Classical de Sitter Solutions of 10-Dimensional Supergravity

We find four-dimensional de Sitter compactifications of type IIA supergravity by directly solving the 10-dimensional equations of motion. In the simplest examples, the internal space has the topology of a circle times an Einstein manifold of negative curvature. An orientifold acts on the circle with two fixed loci, at which an O8- and an O8+ plane sit. These orientifold planes are fully backreacted and localized. While the solutions are numerical, the charge and tension of the orientifold planes can be verified analytically. Our solutions have moduli at tree level and can be made parametrically weakly coupled and weakly curved. Their fate in string theory depends on quantum corrections.