An assembly includes at least one first collection of a plurality of spacecraft intended to be fastened to a launcher during a launch phase, wherein the spacecraft are arranged about a central axis (Z) in a given transverse plane perpendicular to the central axis, the spacecraft having edges along a longitudinal axis and being moreover arranged in such a way that a spacecraft is linked to a neighboring spacecraft of the collection by one edge by means of at least one fastener (B) positioned on the edge, so as to mechanically hold the spacecraft to one another, and a satellites-launcher adaptor to which the spacecraft are fastened in a transverse plane.