I finished this book a couple of weeks ago. Like all of Chambers's books, it feels as though nothing much is going on in them at any given moment, but in a good way. There are interpersonal relationships continuously developing and evolving, there's the discoveries about the planets that the explorers land on, and then there is the revelation about events back on Earth which the explorers, 17 light years away, can do nothing about.
For such a simple and shortish story, I found the revelation at the end to be suitably profound, as well as the way Chambers left unanswered, but in a satisfying way, some of the questions about what had happened back on Earth.