To have a Space Operatic theme to the campaign, or not to have one, that is the question. Hard Science vs Weird Science. Hard Science vs Space Opera level science. I do not mean Space Opera the game, but the whole genre of Space Opera, larger than life heros and villains, vast armadas of starships, or just the hero in their one of a kind Skylark and Lensman ships?
I find I tend towards the more Space Operatic style of gaming, with grand plots, grand villains, and heroic characters taking on the evil overlords...
So do you tend towards Space Opera, or more hard science?
I always aimed for a swashbuckling in space feel, rather than classic SO. Traveller was both to gritty for SO, and too soft for Hardish SF; essentially, it's hardish Space Opera, and of late, Alien, Star Trek, and Star Wars have systems I like better for medium to super soft Space Opera, and Star Wars is adjacent to Spelljammer, IMO, rather than to Trek or Alien.
SO can, as a genre, be very gritty, and yet, very soft on the tech base - see also
Picard, certain episodes of
The Orville, and Niven's whole corpus.
That the tech is doable isn't really the limitation/division between SO/SF in my view... it contributes... but the power of the heroes and villains makes a huge difference.
The Martian (book or movie) is Space Opera to me - even tho' all the tech is within reach - it's about the human triumphant, in a positive way, every bit as humanistic and chauvinistic as
Star Trek. A proper SF approach would have (1) not had things blown over by the windstorm (the winds lack the force to tilt a rover, even at 150kph... only the hopper really stands much chance of being blown about ... ), required much more work to reform the soil to make potatoes grow, probably not have had a single uncooked unfrozen potato for him to plant, not had surplus food left at the base for him to eat while waiting for the plants to grow, not had as much spare material for him to bodge things together...
Proper sci-fi, he'd have been eating algae from the life support, and maybe some shrimp, both shipped live to specifically be a regenerative life support system... and spending a couple weeks just dealing with soil chemistry and his gut flora to get something that could support the needed microbial loads which plants are symbiotic with. Essentially, it's Space Opera because it has WAY too many coincidences in search of HUman Triumph. Realistic? THey return in 18 months, and he's dead, but at least he's got a nifty bit of perchlorate-tolerant microbiome started....