Nasa, the once mighty space agency, has a great collection of images that they share with the public at Nasa Images. Not only is there a wealth of images there available for download in fairly high resolution, they also have very relaxed image usage policies.
Looking at the images below, I could see some up-and-coming indie artists simply putting text over one of these photos and calling it their new album cover. My favorites are from the 1960’s and early 1970’s – the golden age of the space race.