Pushing Ice

A standalone novel (although with a plot allowing for a sequel) with two first editions:


 * Pushing Ice (paperback)
 * Pushing Ice (hardcover)

Plot
The crew of the outer solar system mass driver ship Rockhopper are the only ones close enough to pursue and observe a curious phenomenon first spotted from Earth: Janus, a former satellite of Saturn once thought to be an icy moon, has effortlessly broke planetary orbit and is quickly leaving the system. In order to uncover what this apparent alien artifact was doing near Sol, it must be followed. However, the ultimate destination is unknown.