While this starts as moderately interesting light adventure, it doesn't follow through terribly well. It's fast moving, but thin, and with many flaws.
First off, the science if pretty questionable throughout, and the crucial solution is essentially magic. Kuttner makes little effort to apply logic. A warrior from Earth's early history is able to figure out how to direct a spaceship on an automated intra-system course - all with no more than natural smarts and a heap of alien memories. In general, Kuttner's smart humans are able to pick up modern science and technology without really batting an eye.
The characters are about as two-dimensional as they come. Men are strong, women are supportive, and we don't learn much more about them than that. There's one Oriental in the group, and somehow that makes it clear that he, at least, is not an alien (because I suppose aliens are Caucasian). As is traditional in adventure novels, a man falls in love with a woman essentially at first sight, and despite her fairly substantial character flaws. To be fair, the lead character does deepen as we proceed, and there's a subsidiary character who would be complex if he weren't so peripheral.
Light reading, and a modest novel of its time, but there's no real reason to revisit it now.