By the year 3000, astronomers believed that their giant orbiting telescopes had detected all planetary systems within five hundred light-years of the Sun. Dozens of approximately Earth-size worlds had been discovered, and some of the closer ones had been crudely mapped. Several had atmospheres bearing that unmistakable signature of life, an abnormally high percentage of oxygen. There was a reasonable chance that men could survive there — if they could reach them.

Men could not, but Man could.

The first seedships were primitive, yet even so they stretched technology to the limit. With the propulsion systems available by 2500, they could reach the nearest planetary system in two hundred years, carrying their precious burden of frozen embryos.

But that was the least of their tasks. They also had to carry the automatic equipment that would revive and rear these potential humans, and teach them how to survive in an unknown but probably hostile environment. It would be useless — indeed, cruel — to decant naked, ignorant children on to worlds as unfriendly as the Sahara or the Antarctic. They had to be educated, given tools, shown how to locate and use local resources. After it had landed and the seedship became a Mother Ship, it might have to cherish its brood for generations.

Not only humans had to be carried, but a complete biota. Plants (even though no one knew if there would be soil for them), farm animals, and a surprising variety of essential insects and microorganisms also had to be included in case normal food-production systems broke down and it was necessary to revert to basic agricultural techniques.