Joachim Boaz at Science Fiction and Other Suspect Ruminations is running a series of reviews on generation ship stories. He even compiled a list of such SF tales. I’ve decided to read along. So far he’s covered “The Wind Blows Free” by Chad Oliver and “Spacebred Generations” by Clifford D. Simak (later renamed “Target Generations”). Joachim plans to do “Wish Upon a Star” by Judith Merril next. Science fiction has explored this theme often. Imagining a self-contained society that spends hundreds or thousands of years between the stars presents a wonderful challenge to writers.

I’ve loved the concept of generation ships since 1965 when I was 13 and read Orphans of the Sky (1963) by Robert A. Heinlein. This book was assembled from two magazine stories, “Universe” and “Common Sense” first published in 1941. At the time I thought Heinlein and science fiction must have invented the idea of generation ships, but I was wrong.  I highly recommend reading Wikipedia’s entry on the topic. Both the rocket pioneer Robert H. Goddard, and the space explorer theorist Konstantin Tsiolkovsky came up with the idea in America and Russia. And it was also described by J. D. Bernal in a 1929 nonfiction book speculating about the future, The World, The Flesh, & the Devil.

Because I’m going to discuss the ideas in the stories this essay will have spoilers.

Quite often in the early science fiction stories about generation ships, the crews forget they are on an interstellar mission. This makes for a sense-of-wonder climax based on characters experiencing what The Encyclopedia of Science Fiction calls a conceptual breakthrough. That’s an exciting plot device for the reader but would any generation ship crew ever forget their mission? Right from the beginning of the idea of generation ships in science fiction with “The Voyage that Lasted 600 Years” (1940) by Don Wilcox writers have been intrigued by the idea that the passengers would forget.

A generation ship is a spaceship that travels slower-than-light and takes many generations to reach its destination. Heinlein hit one into orbit by imagining the crew forgetting their mission. Their society collapses to the point where they believe the ship is their entire universe. Because the crew can’t see outside the ship they don’t know about the stars and the cosmos. This is such a delicious idea that Brian Aldiss reexamines it in his novel Starship (1958) (first called Non-Stop in the U.S.).

Now that I’m much older I find it very hard to believe the crew would forget they were on a generation ship. Such forgetting makes for a bang-up plot, but if you think about it, doesn’t make a lot of sense. To forget their mission would require a complete collapse of the ship’s society. Is that even possible? How could the ship continue to function? Writers tell us the ship is fully automatic, but I can’t believe that either.

Evidently, science fiction writers assume such forgetting is a powerful McGuffin to wow their readers. And I loved these plots when I first encountered them. However, I now believe such situations to be too contrived to be realistic. Such tricks by the writer are much like an O’Henry ending. The reader is set up from the get-go. Not that such storytelling shenanigans are bad, but I do think it gives readers the wrong impression about generation ships.

Of course, I haven’t read all science fiction stories about generation ships. Now that Joachim Boaz is systematically reading them for his blog, I’m wondering if any science fiction writer imagined a realistic generation ship. It’s fun discussing this at his site.

Slower-than-Light Travel

Even though Einstein has been validated time and again, science fiction writers have us zipping around the galaxy at several thousand times the speed of light (300,000 kph). The spacecraft Voyager 1 and 2, our only efforts to leave the solar system, poke along at 1/18,000th that speed. Some engineers have theorized we might achieve 1/10th to 1/5th lightspeed with our present and expected knowledge, however, even their ideas are extremely theoretical.

If we could travel at ten percent of the speed of light it would take a whole lifetime to get to the nearest star. Since it will probably take hundreds or thousands of years to travel the nearby stellar neighborhood we’d need the crew using suspended animation or build a ship where humans could live out several generations.

Suspended animation is probably no more realistic than faster-than-light travel.

Building an artificial world that is completely self-contained, self-sufficient, and can travel a significant fraction of the speed of life is not impossible but probably so. Still, it’s a very exciting idea to contemplate. Can we build a machine that works perfectly for 1,000 years? What is the optimal crew size? How do you design a society that can thrive in such a limited environment? How will this civilization get its energy? Will water and air leak out? Will the passengers find meaning in their lives? How would successive generations react when learning they have been forced into a limited role by their ancestors? What if you don’t like where you’re going?

The generation ship would have to contain a minimum viable population (MVP). We must assume it will be a colony ship. Any scientific exploration should be done by intelligent machines – why waste all those lives on just information? In my reading, I’ve seen MVP numbers ranging from 160-5,000. We often see stories now about sending frozen embryos or building machines that can sequence DNA from raw material but I’m going to assume frozen embryos can’t last 1,000 years, and building people from digital blueprints is a fantasy. If we could, it would invalidate the need for a generation ship. By the way, raising artificial children at the end of a long space voyage is a new theme science fiction writers are exploring.

Orphans in the Sky imagines a generation ship where the ship’s civilization collapses and the inhabitants forget they are on a spaceship. I love that idea as a science fiction story, but doubt it would happen. Crews on a generation ship would have lots of time on their hands and education would have a significant appeal. They would have a library of our entire history. They would be in contact with Earth. They would know everything about astronomy and cosmology. For Heinlein’s story to work the original passengers would have to be clueless dumbasses who didn’t care about anything intellectual and refused to teach their children. The original crew would be brilliant with a passionate hope for the mission. They would pass that on. For Heinlein and Wilcox to be right, their descendants would have de-evolve. How that could happen would make a great SF story. I wish Heinlein had written it before writing “Universe” and “Common Sense.”

Clifford Simak came up with a different idea in “Target Generations.” He tells us the original mission designers feared the crew would not psychologically survive knowing why they were on the ship, so hid the knowledge from them. That’s absolutely ridiculous if we think about it, but at least Simak’s realized Heinlein’s idea had problems. That’s what’s wonderful about science fiction, it evolves. It’s a dialog by writers over time.

Chad Oliver offers another twist in “The Wind Blows Free.” The passengers know they are on a spaceship but they haven’t been told it landed hundreds of years earlier. Selective crew members decide the generation ship’s inhabitants are too adapted to shipboard life to leave it. That’s a very compelling idea, but still not realistic. I don’t see how they could hide landing a ship, but more than that, it’s based on maintaining an absurd conspiracy theory. The practical solution to such a problem would be to land the ship and let people slowly migrate to the new world. I do buy that generation ship passengers might not want to leave the ship. I’m an old guy who has become very attached to my house. I wouldn’t want to start over either.

Too often science fiction ignores Occam’s razor to create a compelling plot. I’m hoping we’ll be reading stories where generation ships succeed, or if they fail, fail for realistic reasons. Aurora by Kim Stanley Robinson was an outstanding example of a space exploration failure that made sense.

Children of Time (2015) by Adrian Tchaikovsky did come up with a very real generation ship problem. Successive crew generations became resentful for having their lives committed to a project they didn’t choose. Some even want to abort the mission and return to Earth. This is the kind of realistic challenges I hope science fiction writers will imagine. There’s nothing wrong with coming up with a plot that wows the readers but ultimately makes no sense. A story is a story. But I like science fiction that imagines something that might be possible.

I like to think it’s science fiction’s job to consider all the possibilities before we actually build a generation ship. From early science fiction, we know not to create a society that will forget the mission. I also like the idea we have to worry about the resentment of the later generations. And we do have to worry about getting people comfortable living on a ship to living on a planet again.

We science fiction fans daydream of traveling in space. But can you imagine a future where children born in space wished they lived on Earth like us?

James Wallace Harris, 12/2/19