Okay, that's a creepy alien. That's what pollen would evolve into. Or Nerf.

Everything about this cover suggests the sort of book I loved - in fact I didn't need the book, just this picture. The rocket ship. The metal floor, the ribbed suit, the dome, the red sky. A summary suggests it's high space opera:

From mighty Canopus, capital of the Federated Stars, to the outer fringes of our great galaxy, the Interstellar Patrol was on the watch. Rogue suns, marauding alien intelligences, man-made comets driven by their makers for the conquest of unsuspecting worlds, diabolical conspiracies hatched in the depths of unmapped nebulae - it was the business of the Patrol's mighty spaceships to guard against such cosmic dangers.

Hey, that sounds pretty good. Except they were written in 1928 - 1930, so there was probably lots of talk of Radio Blasters and X-Ray Propulsion and the like.