Endeavor on its last flight, over Moffett Field in Sunnyvale, Calif.

It was a decade of change. And while reasonable people might have disagreed on politics, in 1961 the nation agreed with President Kennedy: sending a man to the moon by the end of the decade was a good thing. Today, it’s hard to remember how important it was back then to get ahead of the Russians, who beat us into space by just a month. But even though I was just a child then, I remember.

I can’t remember a time that there wasn’t an astronaut going somewhere: straight up into the atmosphere and down, like Alan Shepard did for the first time in 1961.  Orbiting the globe, like John Glenn did less than a year later. Back then, we knew our astronauts by name, all of them.

Man walked on the moon some 43 years ago–who in our generation can’t quote One small step for man, one giant step for mankind? Seared in our collective memory is the real time footage of the Challenger disaster in 1986–and the horror that came over the nation when we realized what had happened.  And then the shuttle, orbiting way up there with people aboard, carrying out experiments as they looked down on earth day in and day out.

The manned space program captured our nation’s imagination like nothing else, and then it was just part of our lives, operating in the background, through civil rights protests and war, through hurricanes and elections.

It’s over now, and to my surprise,  it’s almost like losing an old friend.

The Endeavor flew over Moffett Field in Sunnyvale a few days ago, the place where many of its components were made, marking the end of the U.S. space shuttle program, an expensive activity we can no longer afford to fund. Who could have known that in the 21st century, we’d cede our lead to the Russians and be ok with it?

Times have changed.

While scientists and astronauts went about their business way up in the atmosphere, life down here was going on as usual. Imperceptibly, time was passing. The world as we knew it was changing and just as imperceptibly, we were aging.

Approaching the Golden Gate Bridge, where it did two laps

And now, on the cusp of qualifying for Social Security, I watched the Endeavor fly over the San Francisco Bay area, marking the end of an era and also the passage of time.

I’m not sure which I grieve more.