They might have the right stuff, but astronauts are only human. And superstition, sentimentality and the need to commemorate key events affect them just like anybody else. But unlike the rest of us, these folks have the ability to make cosmic gestures with the stuff of everyday life.
What kind of stuff? Some is fairly ordinary before it leaves the grip of Earth's gravity - think stamps and coins - and some is already extraordinary. Some wreckage from the world's worst terrorist incident is now sitting on Mars, for example. And when two bicycle mechanics lofted the world's first manned, powered aeroplane off a windy beach in 1903 they could not have conceived that one day parts of their flying machine would soar through the void, land safely on the Moon - and then fly 385,000 kilometres back to Earth. (You might even say the astronauts who did that had the Wright stuff. Sorry.)
Click through our gallery to see some of the objects that have flown to the final frontier.