Michael Collins, Apollo 11

  Lived: Michael Collins piloted the Apollo 11 spacecraft 60 miles above Neil Armstrong and Buzz Aldrin as they became the first humans to walk on the moon. Collins died at 90.

I recall reading an interview in which Collins's biggest fear was being ordered to depart lunar orbit for home while Armstrong and Aldrin were still on the moon, still alive. That could have happened, that any one of the thousands of possible mechanical, electrical or other kinds of failures could make launching the return vehicle impossible, dooming his two colleagues to remain on the surface. I've frequently imagined Collins keeping that anxiety at bay for- how long? A day and a half? idk-  so he can focus on his job. And of course the enormous relief he must have felt at having them return. 

Would the other Apollo missions have taken place if that did happen? Or would we be left knowing there are two dead men out there every time we looked at the moon? Now there's a morbid thought!