Indirect methods used for solving optimal-control problems, when combined with proper initialization and homotopy approaches, remain attractive for space trajectory optimization, as they are able to achieve fast convergence to a solution of the necessary conditions. In this paper, the extended logarithmic-smoothing technique is revisited and integrated with an indirect method to efficiently generate minimum-fuel time-fixed low-thrust rendezvous trajectories. This approach is considered for three cases, in which equations of motion are expressed in terms of Cartesian, spherical, and modified equinoctial coordinates. In addition, the paper addresses the calculation of the Jacobian matrix of the constraints via an implementation of the state-transition-matrix approach, which avoids the discontinuities of the control along the trajectory. The application of the method to two interplanetary missions from Earth to Mars and to asteroid Dionysus is demonstrated. It is shown that, by exploiting the state transition matrix and the homotopy method, the optimal-control problem becomes amenable to numerical treatment. The numerical results are compared in terms of the percent of converged cases, mean values for final mass, number of iterations and function evaluations, accuracy in satisfying the constraints, and computational time.