Egan opens the hard SF anthology with a story that illustrates the good and less good aspects of hard SF.
The good : he creates an intriguing means of humanity getting offEarth, a means that he explores and explains in terms of the technology, and also looks at the human angle. The technology sees small groups of colonists making their way to Mars via a series of ‘Stepping Stones’ – rotating space stations that capture the colonists small vessel before slinging them along to the next Stepping Stone. It’s not a risk-free business, and families heading to Mars often split their members across several ships, rather than having all their eggs, as it were in one basket.
The bad : at least for this reader, the fine detail of the mechanics didn’t quite get through to me, despite some valiant attempts by Egan to describe the process (I’m sure he was itching to put in some diagrams!). And at one point, rather labours the point by having a young passenger engage in a scientific discussion with an older man, who helpfully points out to her the errors in her thinking, thus enabling a detailed infodump.
The story builds up to a climax as there are problems, and human ingenuity and bravery are called for.