The Kohn–Sham equation is the non-interacting Schrödinger equation (more clearly, Schrödinger-like equation) of non-interacting particles (typically electrons) that generate the same density as any given system of interacting particles.
If the particles in the Kohn–Sham system are non-interacting fermions (non-interacting planets), the quasi particles are used (planets one at a time) the Coulomb potential of the nucleus is used (the Gravitational potential of the sun).