The enmity between Carmen and the head of the Mars colony is really well done too. I detested that woman every time I found her on the page. With good reason, as it turns out. Dargo Solingen was a total headcase and I found it easy to empathize with Carmen. Of course, it was great to see that Carmen’s initiative/revenge is what sets the whole colony on its ear and advances everything they’re doing.
The third act settles into the interaction with the alien species, and I liked that a lot too. The aliens feel very much like Heinlein aliens in his juveniles, and I like the twist with the time element as well as the fear on both sides.
This is old school science fiction in contemporary mode, with a heroine that any SF reader will enjoy. But it’s more adult in some areas that some parents will be willing to share with middle graders.