In the midst of the Space Race, NASA decided upon a radical and risky change of plan: turn Apollo 8 from an earth-orbit mission into a daring sprint to the moon while relying on untried, new technologies. Fifty years after their historic mission, Apollo 8 astronauts and engineers recount the incredible science, extraordinary engineering feats and huge technological challenges that enabled them to go where no one had ever gone before

Watch Apollo’s Daring Mission on Nova, tonight at 9pm on WGBH 2