As the second Rama spacecraft enters the solar system, a better- equipped team is sent to explore it, finding two more alien species.

The characters were more complex in this book than in the last one.  However, the book was not as well written.  I think the collaboration between two authors with their own styles made the difference.  The situations at the beginning of the book ring false, but are fine later on.  Also, there is way too much described in technical mathematical terms and exact measurement.  I don't think this kind of book needs that.