I went through the astronaut phase when I was a kid. I was inspired when Sally Ride went into space, and I wanted to break ground like her -- I was going to be the first woman on the moon, or maybe even mars!
The shuttle was supposed to be a "space bus", inexpensive to operate, taking crews and cargo into space once a week or so. Instead, it proved to be a costly boondoggle, and then a disastrous one. After the Challenger disaster I slowly realized that my dreams of living on a space station, or the Moon, or Mars, would never see fruition. Without the political need to compete with the USSR, we simply had no motivation to continue human space flight.
I can't say anything about the Apollo program that wouldn't sound trite, but I'll say it anyway. The Apollo program was an edifying symbol of what human beings can achieve when they work together. It required hundreds of thousands of people to work on their tiny portion of the heat shielding, or the escape hatch, or the space suit cooling system. Each of them had to get it right.
Then, the astronauts themselves risked the unknown to orbit the moon and then land on it. The crew of Apollo 8 didn't know for sure whether their service propulsion system would ignite properly; if it hadn't, their capsule would have become their tomb, orbiting the moon to this day. The crew of Apollo 11 didn't know for sure that the Lunar Module's ascent engines would successfully take them off the moon's surface.
I am told that the whole world watched as Neil Armstrong stepped onto the moon for the first time. I am told that it brought the world together. Indeed, many people seem to see this as the true importance of human space flight: there's something about our species leaving the planet's surface that makes us appreciate our shared humanity.
As for bringing the world together, Atlantis is now a minute away from deorbit burn. There are now 15,000 other viewers on NASA's live stream, and that's only one of many places to see the Shuttle's final journey.
The truth is that human space flight may be be an impressive show of technology, but it does not result in great science. The truly impressive science coming out of the space program is done by unmanned probes, satellites, and deep space telescopes. These projects are teaching us about the origins of our solar system and our universe. They're also a better value for our money: from 1972 through its encounter with Neptune, the Voyager program cost $865 million dollars, and we're still receiving transmissions from both Voyager craft (and we may well be receiving transmissions until 2025). The space shuttle program, in contrast, has cost $192 billion -- as well as the lives of fourteen astronauts.
So human space flight is logistically impractical and dangerous. And it's not the best use of research dollars. It still makes me glad to know that the good nerds at NASA are continuing to develop craft to take humans into deep space. It feels good to know that we're still pushing the envelope, as the test pilots used to say. I like to think that we can still share a sense of accomplishment as a species when we achieve the spectacular. Maybe human space flight is a place for us to play; a respite from the other problems, such as climate change, that we must tackle together if we are to survive at all.
In the mean time, I some take some hope and some comfort in the fact that 20,000 people are joining me on NASA's live feed to watch the end of this era in our exploration of space.