Over the weekend, my wife brought up the classic argument: is the space program worth all that money when we have so many pressing problems on the ground?�I reflexively made the usual arguments about exploration and knowledge. But half-heartedly. That's because I'd noticed that astronauts on this most recent shuttle mission—the first since the Columbia disaster two and a half years ago—spent much of their time ferrying supplies or garbage to and from fellow astronauts at the International Space Station, or inspecting the shuttle itself for damage, then repairing it.
As Maciej Ceglowski points out (thanks, Bill), that's like the explorers of the 1500s "sail[ing] endlessly back and forth a hundred miles off the coast of Portugal, [and] construct[ing] a massive artificial island they could repair to if their boat sprang a leak." Not to mention spending the whole trip keeping the island going and checking for those leaks, rather than doing a whole lot of anything.
Think of it: in the 24 years between 1957 and 1981, we went from Sputnik to the moon, and then to the space shuttle. In the 24 years since, we've gone from the space shuttle to... er... the space shuttle. The Russians are still using a Soyuz design that's over 30 years old. The space station is a creaky successor to Skylab and Mir.
The real standouts in the past quarter century of space travel have been the Hubble Space Telescope, the probes to the outer planets, Mars rovers, and comet-slamming drones—robots, not astronauts. They're also a lot cheaper (with one Mars mission famously priced less than the production and marketing costs of a single big science fiction movie).
It's not that putting astronauts in space is pointless. But if they're going to go, they need to be doing something and traveling somewhere.