Exploration Interplanetary voyages 14 Human-alien encounters 13 Exploration of outer space 11 Space ships 11 Science and civilization 9 Extraterrestrial beings 8 more ... Scott, Montgomery (Fictitious character) 8 Space flight 8 Sulu, Hikaru (Fictitious character) 7 Astronauts 5 McCoy, Leonard (Fictitious character) 5 Discoveries in geography 4 Interstellar travel 3 Kirk, James T. (Fictitious character) 3 Life on other planets 3 Spock (Fictitious character) 3 Wormholes (Physics) 3 Découverte et exploration 2 Discovery and exploration 2 Enemies 2 Exploración 2 French 2 HAL (Fictitious character) 2 Hallucinations and illusions 2 Headache 2 Helium 2 Indians of North America 2 Indiens d'Amérique 2 Introduced organisms 2 less ...