New Releases by Bob Shaw

When the young son of Elizabeth Lindstrom, the autocratic president of Starflight, falls to his death, Vance Garamond, a flickerwing commander, is the obvious target for Elizabeth's grief and anger. Which, since Elizabeth is not a forgiving employer, leaves Garamond little choice but to flee. And fleeing Elizabeth's wrath means leaving the Solar System far behind, for ever, and hiding somewhere in deep space. Pursued remorselessly by Earth's space fleet, the somewhere that Garamond finds is an unimaginably vast, alien-built, spherical structure which could just change the destiny of the human race...

One planet faces a threat to its survival and so the only hope for its people is to migrate through space by balloon to a sister planet, Overland. The sequel is "The Wooden Spaceships".