It's a fictionalised version of the 1950s USSR vs. USA space race. In some ways, it's very accurate (and quite interesting in being a look at the bit of the space race that the USSR and Yuri Gagarin unambiguously won). Our heroes are likeable and have genuine passion and idealism about getting into space. On the other hand, though, they live under a regime that's obsessed with beating the capitalist West, is happy with a target survival rate of 50% and will have people taken underground, blindfolded and shot. They have flight dates that they want the space program to hit. If those dates are missed, people will disappear. A hushed-up ICBM explosion in ep.3 causes 500 deaths.
The show's premise is that the Soviets had an intermediate test stage between Laika the dog cosmonaut (sent up on a one-way flight in 1957) and the use of actual humans. It's a 17-year-old vampire girl. Her name's Irina Luminesk, although officially she's to be referred to as N44 and there's resistance within the regime to the idea of letting her outlive her usefulness. They don't even really have a reason. There's just an assumption that loose ends should be disposed of, with negligible consideration given to the notion that life might have value.
Irina mostly doesn't let that bother her, though. She wants to go into space. She hates humans, which doesn't seem unreasonable given the purges that have taken place against her people.
Her ally and trainer is Lev Leps, who himself used to be an astronaut candidate. He's terribly nice. Had his superiors really been looking for someone who'd treat Irina like an experimental data point and/or a lump of meat, they failed.
The show's likeable, although not plot-heavy. Our heroes train. Irina puts up with everything they throw at her and in some ways outdoes her human not-colleagues. Natsuki and Misaki watched the episodes too and quite enjoyed them. There's darkness with those Soviet bastards in the background and the question of whether Irina will get disposed of, but the final episode goes in a direction that's optimistic, uplifting and a bit silly. I'm not sure if I quite bought it, but what the hell.
There are, though, some minor quirks.
1. Irina's one of those anime not-really-a-vampires. She doesn't have to drink blood. She can go out during daylight. Garlic, crosses, etc. mean nothing to her. She's not undead, although she sleeps in a coffin. Oh, and she's got elf ears. This isn't really a problem and I liked her, but seriously, come off it.
2. The writing system. I like all the Soviet flavour and I can live with most of the alt-universe quirks. This not-USSR is called the UZSR and its hamburger-eating not-USA rival is the United Kingdom of Arnack. Fair enough. It might have been misleading (and maybe even disrespectful) for this really to be the USSR, because Lev might end up being this universe's Yuri Gagarin.
The UZSR's writing system, though, is blatantly English written in a sort of Cyrillic-like script. I don't think they do the backwards-R for R (even though it's a "ya"), but it's that kind of thing. I found that a bit annoying.
I enjoyed the show. It's nice. Misaki (four years old) once even specifically requested another episode of it. Irina and Lev are lovely and I like their passion for space. I don't know if I'll ever feel the need to rewatch it, but you could do a lot worse.