Yes, I have always thought some elements in 2001 (Kubrick's movie, not Clarke's book) are similar to those in horror works. I do not claim 2001 is a horror movie. But genres are afterthoughts, in the eyes of the beholder. "Horror" is a funny word here (no pun intended).

E.g. aspects of the star ride reminds me of aspects of the "chair ride" to the mountains of the gods in Hodgson's The House on the Borderland. No, of course they are not the same. But they share elements, e.g. approaching things no one has ever experienced, etc.

Similarly, other aspects of 2001 remind me of aspects of Lovecraft's At the Mountains of Madness. E.g. Floyd at the excavation reminds me--when I am in a particular frame of mind--of Lake, Dyer, etc., approaching the beings in that story. Again, it is not the same yet they share some important elements.

E.g. aspects of the movie also, when I am in a certain mood, remind me of aspects of Lindsay's A Voyage to Arcturus. Etc.

I think you are consciously or unconsciously using horror in the traditional sense. I suspect some of the naysayers below who use it in the modern sense may not be aware of the distinction, that there is more than one kind of horror. (No, I do not mean zombie horror vs. vampire horror vs. ghost horror, etc.)

Stephen King's type of horror, whether good or bad, may sometimes scare you or make you jump out of your seat yet it is seldom horror at all in the original, traditional sense of the word; similarly, Night of the Living Dead is a good movie but it isn't a horror movie in the traditional sense of horror. The point is traditional horror does not mean gore.

Horror was traditionally related to, as in Edmund Burke's On the Sublime and the Beautiful, the ineffable, to the sublime, to terror, to infinity, and yes, even to beauty, etc.--no need of gore, decapitation, cannibalism, etc.--unless the gore was beautiful, immense, arresting. The stuff that goes as horror today has almost nothing to do with this. No infinity, no existential angst, no beauty, etc. Something that makes you puke isn't horrifying in the traditional sense. I recall the ending of C.A. Smith's Seed from the Sepulchre: it is gruesome yet beautiful at the same time. That is horror. I think the closest anyone has come recently to visual horror was a few of the scenes in a few of the Hannibal TV series episodes.

I think horror is an art related to "aesthetic arrest" (see Aquinas and Joyce).