The paper is concerned with the vibration problem for the lattice composite attach fitting which provides the interface between the spacecraft and the rocket launcher and has the form of a cylindrical shell consisting of helical and circumferential ribs made of unidirectional carbon-epoxy composite material by filament winding. The axial and transverse natural vibrations of the fitting with a spacecraft are considered. The separation problem for a spacecraft attached to the preliminary compressed and working as a spring fitting is studied. Various dynamic models of the fitting are considered, and the simplest of them which ignores the fitting mass in comparison with the spacecraft mass is recommended. Dynamic properties of actual spacecraft are studied and confirm the technical possibility of the proposed separation method.