B. Minimum Base Attitude Disturbance

During the FFSR2 maneuver, minimum attitude disturbance acting on the free-floating base is required, which is expressed as:

$$\min F\_2 := \sqrt{a\_0^2 + \beta\_0^2 + \gamma\_0^2} \tag{8}$$

In Equation (8), *α*0, *β*<sup>0</sup> and *γ*<sup>0</sup> are employed to depict the base attitude of FFSR2, denoting the Euler angles around the *X*-, *Y*-, and *Z*-axis of Σ0, respectively. The order of rotation around the axes is *Z* − *Y* − *X*.

**Remark 1.** *The MTTP aims at searching for the optimal sequence of waypoints and the optimal joint movements. If not consider the optimal joint movements, the MTTP is the Traveling Salesman Problem (TSP) [18,20]. The TSP denotes that a salesman is required to visit a set of predefined cities with minimum time (or path length), while the time employed to stay at each city is not considered. This is because the time spent at each city has no influence on the optimal sequence of the cities, which also works in the MTTP. Therefore, the time period during which the end effector executes specific tasks at each waypoint is omitted.*
