This month Space Boffins contemplates the missing universe, the nature of humanity and reunites astronaut Nicole Stott with her Space Shuttle Atlantis. Richard Hollingham is joined by theoretical physicist and comedian Dr Fran Day to discuss a new European mission, Euclid, which will be investigating dark matter. He also chats to NASA's new chief flight director in mission control Houston, Holly Ridings, and we hear from Apollo 9 astronaut Rusty Schweickart about his revelations from orbit.You can follow Space Boffins on twitter, @SpaceBoffins. Like this podcast? Please help us by supporting the Naked Scientists