"Icehenge" started life as three short stories in a sci-fi magazine in the early 80s. They were modified, apparently heavily, for this book. Man went to Mars and the asteroids, but not much further. Most everything is run by a corporation more intent on exploiting what and who they have than expanding and exploring. Change comes slow now that humans life for about 600 years.
The first story is about a woman on a ship that is supposed to be the last piece of a secret mission to build an interstellar space craft. They meet with two other space craft that have gone missing over the last decade and their ship is supposed to be incorporated into the new space ship. It'll take a long time to get where they want to be, but they have the time. What they don't have is a recycling system that will get them all the way there. They'll be short just a few years and they need her help to make it work. She does her best and returns to Mars where a brewing revolution will help distract those in charge from the ship fleeing the system. The revolution is put down brutally.
The second story comes decades later. An archaeologist who lived in a dome that was collapsed during the revolution finally has permission to investigate the ruins. He's old enough that he really shouldn't remember any of it anymore. While researching there, a ring of standing ice blocks is discovered on Pluto. It's much like Stonehenge or some similar structure on Earth. He discovered a crashed rover on Mars with papers that indicate the henge was built by a group escaping the star system using stolen ships and the involvement of the woman from the first story.
The third story comes later still. While there has been some reforms since the corporation was forced to admit it's brutality in the revolution, they're still pretty much in charge. Mankind has expanded on to Saturn and beyond, but still not out of the star system. The great grandson of the archaeologist in story two is a historian. He talked to someone at a New Year's bash who makes a believable claim about building the icehenge. This starts the historian on a mission to correct the history. If not the fleeing revolutionaries, then who?
Kim Stanley Robinson, the author, does good work, but often his books get bogged down and you have to wait until the last 100 pages for the story to pick up again. He's just lucky his books are so good. His Mars Trilogy pretty much eliminated the need for other Mars colonization books since he covered it so thoroughly. Since this book is three short stories that's not such a problem as it is with full novels. The first story goes pretty well. The second gets kind of tedious until the archaeologist goes on his one man quest across Mars. The third has places where you think the author has completely lost the thread and then he jumps into or out of a flashback and brings you back into the story.