I watched the pilot of The Expanse and gave it benefit of the doubt on an implausibility or two. Making decent film or video SF is tricky and the line between handwavium and hokum can be pretty thin.
In the first twenty minutes of episode two, a crucial complication depends on the inner door of the airlock a small spacecraft being routinely left open. I have trouble with that: it creates an avoidable single point of failure. It's stupid engineering. Then we find out the acceleration chairs don't support the astronaut's head and neck, despite the ship being capable of considerable thrust, possibly even as much as the previous episode showed requiring special medication to endure. Yet this is not a problem. And then--
Then, in a scenario similar to the one at the heart of Robert A. Heinlein's 1948 short story
Ordeal In Space, a character goes out on the hull to repair Something Important. The spacecraft is apparently under some acceleration -- and the character doesn't have a safety line.* While attempting the repair, a wrench slips from his hand and goes flying away. No safety line on people working on the hull I might grant, especially in an emergency, especially with some of the alternative hardware already shown. But no lanyard on tools? No. Ballistic junk is already enough of a problem in 2015 that when ISS crew is working out on the hull. their tools are on short cables, connected to the worker or the space station. It's routine when working on the outside of tall structures; it's not uncommon for divers. An advanced spacefaring civilization would be very cautious about this.
When your story counts on bad engineering that none of the characters find remarkable, you've lost me. You don't care enough about suspending the viewer's disbelief to even try to fast-talk your way through it -- because you either didn't notice, or figured no one watching would -- and that ruins it for me. It's either ignorant or condescending.
I may watch more of the series; the visuals are pretty good. But the science -- no, the
technology -- isn't.
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* Heinlein's did, if I remember correctly. Then, for a logical reason, he has to go farther than it will allow.