I’ve gone off the previous design – completely. It’s a good image, but it makes the book look like a children’s sci-fi novel. Not what I’m aiming for. I keep gravitating back to the image of the little man from the first design. Here’s another attempt, using him …
Other news: the manuscript has come back from one pre-press reader already, with far fewer objections than I anticipated and some useful suggestions.
Darryl Sloan 
Good job that you scrap the previous one. The reader would never delve into details as deep as you did to interpret the meaning. Everybody would think it is about space travel by just looking at the cover.