Synonyms for Cosmonaut:

n.

capsule, booster, Cape Canaveral, communications satellite, apollo, aerospace, blast off. aeronaut (noun)
pilot, passenger, captain, balloonist, copilot, martian, aviator, aeronaut, spaceman, alien, astro-navigator, airman, astronaut, rocketeer, flier.
astronaut (noun)
pilot, rocketeer.

Other synonyms:

blast off, Cape Canaveral, apollo. capsule. booster. Other relevant words:
booster, capsule.