Mentusa Chronicles 3: Dead Reckoning. Mentusa, #3

Some journeys aren't measured in distance... but in trust. A routine maintenance mission should have taken only a few days. Instead, Captain Kesla and the crew of the Mentusa find themselves questioning decades of accepted navigation, confronting evidence no one expected to find, and uncovering the legacy of people whose careful work has been quietly protecting travellers for generations. As old records, forgotten observations, and patient engineering begin to reveal an extraordinary truth, the crew discover that experience can be every bit as valuable as technology-and that sometimes the smallest voice in the darkness is the one worth listening to.
Dead Reckoning is a warm, character-driven science fiction novel celebrating curiosity, craftsmanship, friendship, and the simple belief that bringing people safely home will always matter more than finding the fastest route.