Space Opera is a science fiction role-playing game published by Fantasy Games Unlimited. The basic game rules include character construction, aliens and monsters, combat, starship construction, and world creation. The character classes included armsman, astronaut, tech, research scientist, medical scientist, and engineering scientist.
From the back cover of the rulebook:
VOLUME 1 covers the generation of characters, their attributes, skills, career possibilities, and the effects of their planets of origin. Variations for alien races are presented. Psionic talents are explained. Details for running, maintaining and repairing a starship are given. Five starships, complete with deckplans are given.
VOLUME 2 presents a wide selection of equipment and weapons for a variety of technological levels. Combat, both on the ground and between starships is covered. Detailed sections on starship design, world creation, interstellar travel and commerce, and planetary cultures fill out the book.
Note: Volume 1 and 2 are in the same, single rulebook (CORRECTION: Maybe depending on printing however they are published separately as well).