Abstract The aim of this paper is to introduce a new buffering mechanism in impact reduction during assembly process of two space vehicles. Probe-cone mechanism, due to its computational easiness, is employed to study impact interaction between multibody systems. The proposed buffer with a compact structure includes a probe equipped with axial and torsional flexibilities during impact condition. Since all constraints in the problem are holonomic, the unconstrained form of Lagrangian approach will be used to derive the system’s equations of motion. The Lankarani-Nikravesh contact force model, because of its advantages in multibody systems, is applied to investigate dynamic behavior of vehicles during impact-contact event. A key factor in capture process of two vehicles is to determine the proper parameters of buffer. To do this, a strategy will be introduced to evaluate the coefficients of buffer. First, the theoretical model is solved and the obtained results are verified by those recently reported for special case related to impact analysis of two space vehicles carrying flexible probe. Second, the entire capture process will be built in MATLAB/Simulink’s SimMechanics multibody software to ascertain the correctness of theoretical model. Then, a simple ground-based experimental setup will be established to only prove the effectiveness of the proposed capturing system. The obtained results indicate that the proposed buffer leads to considerably reduce the peak value of impact force, to remarkably increase total contact time and to successfully perform capture process.