I didn’t see it, but all day I clicked on pictures and videos posted by my Twitter and Facebook friends. I have been fascinated by the space program since Alan Shepard became the first American in space in 1961. Ten years later I watched him hit golf balls on the moon. I must have consumed gallons of Tang after NASA used it on John Glenn’s Mercury flight. I was home sick that January day in 1986 when the Space Shuttle Challenger exploded 73 seconds into its flight. I watched the explosion over and over and wept. Listening to WTOP on the drive home from work today I heard several eyewitnesses to today’s flyover talk about how they wept as they watched the Discovery make this last flight. I feel a sense of loss – not only for the shuttle program but for the national optimism that made it possible.