A 75-year-old man with a heart condition, mourning the recent loss of his wife, ends up the first space tourist? Sounds like a cinematic essay question for a test on willing suspension of belief. Give Richard Dreyfuss an A. For “Astronaut” (2019). This elegant little film takes every implausibility (and don’t worry, there’s more than I’m mentioning here) and twists them back around until they’re art, like extraterrestrial origami. And bless Dreyfuss for saving his typical blowhard, scenery-chewing arrogance until the one moment where it actually works. It’s not the best movie this year, but it’s a most pleasant surprise.