. . . . . . . "Payload mass is the mass of the payload carried by the craft. In a multistage spacecraft the payload mass of the last stage is the mass of the payload and the payload masses of the other stages are considered to be the gross masses of the next stages." . . . . . . . "Payload Mass"@en . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . "M_P" . . . .