It's not hard scifi, but so what? Most scifi isn't hard scifi. Ben Bova's Red/Green/Blue Mars trilogy would count, I think. Nothing too fantastical there, just

It's not hard scifi, but so what? Most scifi isn't hard scifi. Ben Bova's Red/Green/Blue Mars trilogy would count, I think. Nothing too fantastical there, just an extrapolation of existing science and technology to terraforming Mars. But then you don't get any aliens or speculative technology that way. Which most future science fiction is interested in. That or robots and galactic colonization. Dune and Foundation are just as fantastical in their own way as a Remembrance of Earth's Past. And yet, they're classics and cornerstones of modern science fiction.