u/Carpe_Carpet

Cover: the science officer in the rags of his uniform, fighting off these crab-rat things with a rake(?). Classic pulp paperback art.

This was a book I liked as a kid, but I lost my copy during a move and it's too obscure to find again. Hoping someone recognizes it.

What I remember:

- Pulpy mid-century sci-fi, short novel, mass market paperback (possibly an Ace Double era thing?)

- Setup is basically Robinson Crusoe in space

- Protagonist is a science/exploration officer from a Star Trek Federation type good-guys faction

- He crash-lands on an extremely hostile jungle death planet along with the queen of an unfriendly star kingdom and her two kids: a teenage son and a younger daughter

- also they're being stalked by a mercenary who is the last surviving native of the planet, returning to capture the royals for a different, less powerful but more evil star kingdom

- They survive by sciencing their way through it, Mark Watney style. The protagonist whips up some poison gas, uses electricity from the wrecked ship to kill off the local predators, and starts farming land that should not be farmable.

- The main natural dangers are some kind of crab-rat critters, wasps, and the sheer speed with which the plant life grows (e.g. the vines would grow around and strangle you if you slept outside).

- The memorable part was how hilariously successful the protagonist is. Within a few weeks the jungle is all but tamed, the mercenary is ready to switch sides for a chance at making the planet habitable, and when they're rescued the kid is crowing to his dad about how he wants to be a federation officer instead of a space king.

- Oh yeah, and he uncovers some ruins showing that the Scary Jungle Planet used to an edenic garden and home home of (maybe alien?) high tech Precursors

Think "The Martian" if you reduced (not removed) the science explanations by 80% and replaced them with pure gleeful power fantasy.

No character or planet names stuck with me. Anyone recognize this?