At twelve David misplaced him at the Air & Space Museum. When found Bob was attending a talk on the nature of flight, dominating the Q and A.
Retired now, David follows Robert’s work as an aerospace engineer, but knows he will die long before Robert takes his trip to Mars.
Will David somehow see that, having journeyed through the black hole at the center of the galaxy, and gladly observe it all? Darkness perhaps at the event horizon, but the universe’s core must be light.