Planetes was really well received but yet it doesn't have an anime continuation even though I hear the manga goes well beyond the anime (I think until exploration to Jupiter?).
I can't seem to find any reason why it's not happening, is it because it didn't have enough viewers or is it because it's been too long since the anime last aired? Usually anime that won't get a conclusion has an explicit reason but this one doesn't and it's really bothersome.