<p>Single-axis slew maneuvers are utilized in various fields, including space missions. In spacecraft attitude control, fuel-optimal control is a significant area of research. This paper presents a closed-form solution for the absolute effort minimization problem for single-axis slew maneuvers under spin-to-spin boundary conditions and a fixed final time. Six angular acceleration profile structures, including the previously defined bang-off-bang structure, are introduced, and the problem is solved by classifying the boundary conditions of the state variables. Additionally, cases in which no optimal solutions exist for specific final times are discussed, and the proposed solution is validated through numerical examples.</p>