Waters of Mars (2009 special):
DOCTOR: Imagine it, Adelaide, if you began a journey that takes the human race all the way out to the stars. It begins with you, and then your granddaughter, you inspire her, so that in thirty years Susie Fontana Brooke is the pilot of the first lightspeed ship to Proxima Centauri. And then everywhere, with her children, and her children’s children forging the way. To the Dragon Star, the Celestial Belt of the Winter Queen, the Map of the Watersnake Wormholes. One day a Brooke will even fall in love with a Tandonian prince, that’s the start of a whole new species.
Kill the Moon (s8e6):
DOCTOR: Lol jk. The moon hatches into some pterodacyl thingy and that inexplicably inspires the people who wanted to kill it to go become the first space explorers and spread across the universe.