The wip looks fine, if a little small - and will certainly look better with improved planets. The problem with achieving a 'style' from the Terran Trade Authority books is that there wasn't a particular style to them. They were rehashed book covers or unused art from many illustrators, and so were comprised of many styles. To hazard a guess, I'd say your scene looks most like the style of Angus Mckie. Looking forward to progress.