I waited on the library list a long time for this book and it was worth it. It was definitely science fiction, but more like The Martian than anything. The setting is the year 2066 on a space ship, explained to be similar to the current International Space Station, but on a much larger scale, was doing routine maintenance when something decelerating into Saturn's orbit was observed. Now ensues a space race between China and the United States to figure out what this object (alien species????) was. It goes into fairly deep technical detail, but nothing overwhelming. Enough for the science nerds to be satisfied, but not so much that non-science minded people won't be satisfied.