NASA last launched astronauts into space with its final Space Shuttle mission in the summer of 2011. But, nine years later, a rocket built by SpaceX lifted off at the Kennedy Space Center in Florida and carried two astronauts to the International Space Station. How did this private company, in less than 20 years, go from a fledgling startup to one of the biggest players in space? To answer that question, I've brought on Eric Berger.

Eric is the senior space editor at Ars Technica and the author of Liftoff: Elon Musk and the Desperate Early Days That Launched SpaceX.