The filming was finished before any human being set foot on the moon, yet Kubrick was able to accurately predict what the surface of the moon would be like.
Also.. the idea behind the space station using centrifugal force to mimic gravity is not only plausible, but at the time it was revolutionary. We had no space stations, or orbiting satellites at the time, and most conceptual ideas that pointed in that direction had little to no practicality. That was probably all Arthur C. Clarke's brilliance more than Kubrick's, which is why it's not surprising that 2001 is such a masterpiece. Take a masterful filmmaker, with a nearly unstable desire for perfection, and a brilliant science fiction writer, inventor (the dude INVENTED satellite communication), and all around badass, and you get 2001's a space odyssey. Nuff said.
2010 was what I expected, far from perfect, but it successfully used nostalgia as a crutch, and gave more of something I loved. Probably wouldn't watch it again though..