I received an ARC of this book from NetGalley in exchange for my unbiased opinion. 
 Helen, Yoshi, and Sergei are astronauts who have been chosen for Prime's goal of sending humans to Mars. The three will go through a 17-month simulation, and if that goes well, they will take an actual 4 year voyage to Mars. The books alternates between their points of view, as well as Helen's daughter, Yoshi's wife, Sergei's son, and a Prime employee. 
 I felt that this book tried to cover too much territory by taking on so many viewpoints. I would have enjoyed a book focusing solely on the simulation, and I think the family member's stories could make good books on their own, but with 7 different viewpoints, I felt like we didn't go deep enough into any of them to feel invested in what was happening. The one plot point that caught my attention was left completely at loose ends at the conclusion of the book. It wasn't a bad story, but it was one I had to push myself to read.