For a while WJLP's Petomaniac was one of the best free surf/instro albums you could find on bandcamp. They've since decided to get paid for it, though still pretty damn affordable (and very worth it) at €5. Though they've sprinkled instrumentals here and there since then, but they're back to a full instrumental record with a spacey sci-fi movie theme.
Their take on Sci-Fi generally means a lot of organ, healthy reverb, and a pretty casual tempo. If that sounds pretty straightforward, perhaps even trad to you, then yeah. Man... or Astro-Man? this is not. But that's fine! These are fun, well-produced and catchy instrumentals and there is that sense of wonder and discovery that is often associated with space songs. And then there's songs like "Lifeguard" standing in as their straightforward surf pounder. And a western track in "Rode Hard and Put Away Wet". Clearly space is a theme but not a rule. They have the sort of flexibility, yet grounding in fundamental well-crafted surf that I think invites a Los Straitjackets comparison. And like LSJ, I expect this to have a pretty wide appeal too.
As far as I know, this is digital only, though it is finding its way to non-bandcamp platforms soon.