Just finished it this morning, got through all 26 episodes in about 3 sessions. Dang, wow. Well done. One of the best endings ever, and now one of my all-time favorite anime.
I found the manga last year, some Booksales have Volume 1, always and only Volume 1. It's great, a dense and satisfying read. A week ago I got the anime and finally found out how the rest the story worked out. So the series ran 6 years ago and is already, rightly, considered a classic. Again, well done. At least two specific shout-outs to the defining hard-sf classic The Cold Equations, an especially harrowing Break The Cutie night journey performed on the naive ingenue, and it all works out. Earn your happy ending, indeed.
One thing I've learned as characteristic about truly great art is that it makes mediocre art look lame in comparison. Firefly is next on the queue, and it simply cannot compete. Obviously Firefly's way off towards the softer end of sci-fi, but still, the realism in Planetes defines how peril works, how grandeur works, how people relate to each other and live their lives. God, I loved that bit near the end, how Nono unwittingly calls the terrorist out: "Countries? Oh, those old-skool Earth things. I'm a Lunarian." Glory.
Watchmen, The Wire, Planetes, you get a taste of the really good stuff, and you wonder why isn't there more like this? You look around, regurgitated variations of the same old fluff. Like eating nothing but icing and cotton candy. How can people live? Don't they long for substance? To be sated and made full, to grow?
Maybe that's unfair. We can't all be Alan Moore or David Simon. But it doesn't take genius-level talent to reach for truthfulness and authenticity.