Expendable

From the back cover:

Under the benevolent leadership of the League of Peoples, there is now war, little crime, and life is sacred... unless you're an Explorer. The ugly, the flawed, the misfit, the deformed, they are the unwanted, flung to the farthest corners of the galaxy to investigate hostile planets and strange, vicious creatures. Out there, there are a thousand different -- and terrible -- ways to die.

Festina Ramos belongs to the well-trained, always-dwindling ranks of ECMs (Expendable Crew Members). Now she and her partner, Yarrun Derigha, have been ordered to escort the unstable admiral Chee to Melaquin -- the feared "Planet of No Return" -- which has swallowed up countless Explorers before them without a trace.

Synopsis from Open Library.