Abstract: An orbital assist module and an interstage for a launch vehicle. The orbital assist module includes a cylindrical outer wall and a support structure secured to an inner surface of the cylindrical outer wall. The support structure defines a plurality of fuel tank supporting zones, at least one of the zones supporting a fuel tank by means of securing formations. A plurality of nozzles are connected to the fuel tanks by means of fuel lines and a plurality of valves are mounted in the fuel lines. The interstage comprises a cylinder having a leading and a trailing end and an explosive connector at the leading end for connecting the interstage to a trailing end of a launch vehicle motor. A connecting bracket is secured to the trailing end of the cylinder for connecting a second launch vehicle motor to the cylinder.