The Burning Bridge — Poul Anderson

Fleet Captain Joshua Coffin leads a cast of characters fleeing an unforgiving and unyielding Earth, to settle a colony around a far-away star. But just as they are reaching 'the point of no return,' they receive a short message from Earth indicating that things are settling down and giving them the choice of perhaps returning home instead of fleeing into the desperate unknown. Hard choices need to be made. Is Captain Coffin up to the task, and at what cost?