Murray Leinster paints the following picture for us: It is the time of the Cold War. The UN has declined to attempt to launch an artificial satellite into orbit, so the USA has gone ahead and done so on its own. Said satellite is a space station, with a small crew aboard. (I know now, though I did not when I started the book, that these events are detailed in a previous novel.) Now Joe Kenmore is commanding the first mission to fly a manned ship up to the space platform, bringing supplies and weapons. This is not a tale of alternate history; it was published four years before Sputnik 1 launched, eight years before Yuri Gagarin became the first man to make it to outer space. It is speculation on the future which has become our past.
You'd think that would get in the way. It doesn't so much. History didn't come close to matching what is depicted here, and this is not how we actually launch spacecraft, and so on and so forth. I know that. That's okay, though, because what we're told still has a sort of authentic feel to it. Like, I can totally see some engineer trying to solve the problem of achieving escape velocity and going, "Okay, what if we had a bunch of little jet engines, and then some JATOs..." I don't know how the science checks out, either, but to me as an uninformed reader it at least feels real enough to support suspension of disbelief when it's coming from a time when all of this was theoretical. I really enjoyed the first few chapters in that regard.
Unfortunately, there's more to it than that. It's a wonderful example of how science fiction proven wrong when history caught up with it can still be quite enjoyable. It's not such a stellar example of the actual fact of writing, though. I give some allowance for the time in which it was written and the social and political biases it exhibits as a result; I'm not complaining about that. (Much.) It's very repetitive, though. We're told things multiple times, as though we won't remember anything from one paragraph to the next, and the same words and phrases are used over and over and over again. Besides that, after a certain point in the book, things start to go awfully fast. I don't mean that the action is fast-paced. I mean that in-story technological advances happen with a speed and a lack of testing, setbacks, red tape, or unexpected results that utterly defies everything I know about development. My suspension of disbelief was totally fine with "Americans get to space first, in the form of a manned space station", but could not survive this.
I also, even allowing for the times, have trouble believing that anyone could look at this space station being loaded up with weapons, especially when they're prepping to stock a prospective moon base and are absolutely overloaded, and think that it could only be interpreted as a threatening move by people trying to make the USA into the bad guys. I mean, hello. What part of "the US has a space station full of missiles they can throw around and no one else has figured out how to get there yet" doesn't sound like it might be a little worrisome to certain other nations?
Ultimately: Neat historical curiosity for the first few chapters, but not that great overall.