Probably every long-time science fiction fan has read Heinlein’s short
story “Universe”; as the first story to describe the now familiar
“generation ship” concept for planting space colonies, it’s been widely
anthologized. What I’d never realized is that Heinlein wrote a sequel to
it called “Common Sense”. Orphans of the Sky is simply the
pair of tales back to back.

The gimmick is simple. Earth launches a colony ship; it’s supposed to
get to Proxima Centauri a couple of generations later. But there’s a
mutiny shortly after launch, and in the ensuing fracas most of the
officers are killed. The remaining loyal crew drive off the “muties”,
but in the meantime the ship’s main drive has been turned off, and the
ship drifts quietly through space….for hundreds of years.

And then our story begins. The descendants of the mutineers, now
“muties” in truth, occupy the center of the ship and the areas of low
gravity, including the main control room; the descendants of the loyal
crew live in the high-gravity areas in a theocratic society based on what
little they can understand of the remaining science texts.

“Universe” has a warm place in my heart; it was truly a great story when
it was written. But the ideas in it have become commonplace, and the
writing isn’t stellar. I’d recommend this book for the Heinlein
completist only.