In the 1960s and ’70s, those working in the NASA program were preparing to launch the first rocket that would land on the planet Mars. In 1976 we landed two manmade objects on Mars—Vikings I and II. Never before in history had mankind penetrated that far into space. I was one of the principal investigators on the Viking program, having designed two major research projects.

The timing of these programs is unique: We were the microbiologists, and we were required to have our projects designed and ready six or seven years before launch. The engineers needed adequate time to design the spacecraft to hold it all. So several years before launch, we had essentially finished our work. But since we were still getting paid by NASA, they felt compelled to find something useful for us to do.They felt compelled to find something useful for us to do

One of the program managers called a meeting for the 30 or so of us involved. He began talking about the real challenges of space flight, predicting that after we explored our own solar system, we’d move into interstellar space—go to the stars. This was the topic we were to explore.

The nearest star is Alpha Centauri. It’s 4.1 light-years away from earth, which means that a beam of light traveling at a speed of 186,000 miles per second would take 4.1 years to reach Alpha Centauri.

Needless to say, we were a long way from traveling at that speed. I did the calculations, and even if we managed to build a rocket that would travel 100 times faster than anything we’d ever designed, it would still take 830 years to get there and another 830 to come home again, of course!

As someone said, “No more coffee breaks—we’d better get going!”

Obviously, sending an astronaut wouldn’t work; no one could live that long. There have been movies made about suspended animation—putting humans into some kind of deep sleep, where they don’t age—but we don’t know much about that. What we do know is that humans live 60–80 years, and then we die.

The only real solution is to put men and women together on a spaceship, and then advise them to follow the first commandment: Be fruitful and multiply. They would have children, who would marry other children, on and on and on, for many generations.

But it doesn’t take a rocket scientist to see that this plan presents sociological problems, as well as an engineering issue. How would successive generations of people survive for the 830 years out and the 830 years back?

Food is an obvious problem: What will they eat? Remember, there is nothing out there. Absolutely every scrap of everything they will need to live must be taken along or grown. There are no resources in space. Nothing.

Pondering this problem occupied a lot of NASA time. One possible solution is the extensive use of algae. There’s sunlight in most of outer space, so algae could be grown on the collected sweat and urine from the humans. But people don’t like to eat algae. Russian scientists at one time considered feeding the algae to chickens, and then the people could eat the chickens. But that leaves you with a feather problem. Feathers can’t be recycled. What can you do with the feathers?

Of course, it didn’t take long to realize that the problems of space travel are almost the same as the problems of planet Earth: feeding a growing world population, supplying clean water, dealing with wastes of all kinds. This NASA project had many useful applications.

Waste was a big issue. What to do with it? Throw it out, or jettison it, like the spent fuel containers? But one of Newton’s theories is that if you throw something out of a capsule traveling that fast, it will just go along with you. You can’t get rid of it—but neither can you afford to waste it, whatever it is.

Other problems abound: If a group of people are confined together for 830 years, how can you make them get along? The history of mankind tells you that there’s never been a 40-year period without one group of people deciding to eliminate another. In Jewish history, 40 years of peace is a very long time indeed.

Leisure is another issue: What will the people do? Once the spaceship is en route, only a few minutes a day will be required to run it. What will everyone do with all that leisure? Unless we can design projects to successfully occupy time, problems will result.

As our seminar progressed, we discussed all these issues. Then another one popped up that fascinated me: How would the adults teach their children about themselves and their mission?

Think about it: For 830 years, all they have is the one instruction manual they started out with. But we know how we feel about old instructions—if an appliance handbook were written in Elizabethan English, we’d ignore it. Junk it! It’s too old to be practical. Even maps—we don’t follow old maps, we correct them!

But here’s this spaceship full of people. If they junk the old instruction manual, what will happen? If they start fiddling around, tinkering with the maps and the navigational system, one thing is guaranteed: They’ll get lost. And then how will they land the thing? And get back? Would that happen?

At the NASA meeting, a professor then made an interesting suggestion. “There are very few precedents for this kind of situation,” he said. “How does a society pass down its mission and beliefs to succeeding generations? I think we need to study the Jewish system. So far as I know, they’re the only group of people who, for thousands of years, have managed to hand down their traditions intact to each new generation. We should study the Jews, and see how they did it.”

Now that was interesting, more than enough to set my own mind to work, long after the session ended. I came to some additional considerations myself.

As Jews, we do indeed have a continuous debate going on. Every day, wherever there are Jews, they still debate and discuss what exactly Moses heard from G‑d, and how that applies to the problems we face this afternoon.

For several thousand years, our concept of our mission has remained real. It’s not a hypothetical. You can’t study the Talmud without gaining the sense of the continuity. I can look and see what was added. I may know that this did—or that did not—come down from Sinai, but the message we received at Sinai is undiluted. It’s as clear and precise today as it was when the Torah was given. The people who are guiding Jewish destiny know exactly what they’re doing. They’re successfully transmitting it to their children.

But the truth is, there’s a bigger problem for How does a society pass down its mission and beliefs?multi-generational space travel than just retaining a sense of mission. The real problem is that after the first two hours, after the ship leaves the gravitational pull of the earth, from that moment on, everyone, for all generations, will live in a weightless environment. Don’t get me wrong: I love weightlessness. Leaping from place to place, dropping things that don’t fall. It’s great.

The point is, for 830 years, they all will live in a world with no gravity. The very memory of gravity will become so distant that it won’t be more than a legend, something that existed far in the past. But assigning the concept of gravity to the ancient bin of legends—along with trolls and angels and talking snakes—means that when they need to deal with it again, when 830 years later they come within the gravitational pull of Alpha Centauri, they won’t have the vaguest notion of what gravity is, or how it works.

It’s not even something as basic as figuring out how to land the ship. It’s more fundamental: In a weightless environment, there is no up or down or front or back. There is no direction. So how do you know how to orient the spaceship when you want to land? And if you tore up that part of the instruction manual 800 years ago, you’ve got a problem. Even if you saved the manual, you have to learn—from scratch—what gravity is.

How can you teach the concept of gravity? It’s different than transmitting a common mission. It’s much harder: you have to transmit a concept that’s not real, something that no one present ever experienced. The concept of reality that the spaceship people lived with for 830 years is not the model they can live with once they land.

So I thought about it. If I were a principal investigator on that mission, I’d do it this way: I’d choose one man in the entire group. Make it a trustworthy guy, maybe someone who’s a little naïve, but someone I could trust.

Then I’d say to him, “Abe?”—and yes, I’d call him Abe—I’d say, “Abe? In addition to all that other stuff you’re worrying about—where the food will come from, how to get rid of waste, how to keep wars from breaking out—there’s something else you have to consider. You have to learn which way is up.”

I’d tell him, “Abe, learn which way is up, which way is down. Learn the difference between transient and permanent. Learn to distinguish between ephemeral and real. And Abe, you have to teach that to your children, and have them teach it to their children, and on and on and on. Because if you miss even one generation, you’re all lost. It will all disappear. People will not like the message; they will ridicule you, beat you, shoot you, gas you. But you must do it, or the whole mission was a waste.”

When you think about it, the fact that you are reading this essay is pretty good evidence that when Someone tried this experiment once before, it must have worked. Not perfectly, of course. But well enough.