Today, albums featuring celestial bodies or space on the cover. No Holst's Planets.
Paul Horn - Jupiter 8. It's widely recognized as New Age (ambient, jazz), so lots of album covers of New Age music featured pictures of space.
EXO - Sing For You (Korean version). It's EXO, I don't have to add anything more. I chose this cover over another also featuring space because there is something poetical about the space whale and an astronaut. The oceans are less known and researched than the space is, so I find it a beautiful parallel.
Mike Oldfield - Crises. I admit, this cover has haunted me ever since I learned about this album. It's the Moon over the solitary towering building. Some people know that Oldfield is among my favorite artists, and I always imagined this cover as to show the Earth after a cataclysm - with one building towering above the sunken city.
ELO - Time.
Sources:
Discogs
Wikipedia