Again straying away from being a social parable, as far as I could tell, this episode was more of a general science fiction story with a twist at the end, which unravels the more you think about it.
Sat on the Launchpad, moments away from beginning the first manned flight to Mars, reports of nuclear missiles in the air mean that the five person crew have to make a choice; abort and deal with the outcome of the missile strikes or continue the mission and perhaps never know what happened on Earth. Choosing the latter, the gruelling 7 month mission takes an increasingly high toll on the crew's mental state.
So this is another episode I'd describe as "fine" rather than "good". The performances are good though, it's an ensemble piece - so it's not fair to pick anyone out in particular, but it's also interesting that this is the first episode not to have a lead actor with some name recognition - at least not to me anyway.
The story is only OK though. We settle fairly late in the episode (too late really) into the crux of the story, that one of the crew comes to believe that their situation must be a simulation, rather than the real thing and decides to test his theory. There might have been more in this aspect of the story, but it's over too quickly to get emotionally involved in it. One character literally talks about "The Great Filter" as a concept. Which again, in retrospect, I think perhaps is cheating slightly, when you have a character spell out what the shows theme, rather than arriving there organically. And the ending. . . well what actually happens? Both options, neither.
Again, nothing special, but the episode was OK.