Today is the anniversary of Apollo 13 running into trouble. That was forty years ago, in April 1970. On the way to the moon, a fault in the electrical system caused one of the Service Module's oxygen tanks to rupture. The crew had to abandon the Command Module and live in the Lunar Module during its completely out-of-spec trip back to Earth.
Heat, water and scrubbers for carbon dioxide were in critically short supply. But these men, who were half way to another planet, managed to make do for a journey back to Earth. Their computer system was about the level of one of today's BlackBerrys. To supplement its output, they took manual readings of their position using navigator's instruments from the 1700s as their course changed (knocked off course by the venting oxygen tank) and calculated their trajectory on paper. Against all odds, they made it back to a safe landing.
I can remember watching this with my heart in my mouth. I knew they could get back to Earth - it's pretty big - but I didn't think they'd get the trajectory right and splash down without burning up. They did, though.
The quote that came out of all that was, "Houston, we have a problem."
I love manned space exploration. I know many others disagree, since robots can do much more and see much more without requiring life support. But I want to go, and I want others to go and tell me what it's like. And I salute heroes like the crew of Apollo 13.