By Megan Ray Nichols of Schooled by Science
We’ve dreamed about exploring the cosmos for generations, and our technology has finally reached a point where that dream might be within our grasp. One thing we’re missing is propulsion technology — we don’t have warp drives or hyperdrives to carry us faster than the speed of light. Yet, anyway. One way to get us out into the universe without that kind of propulsion is to build a multi-generational ship. What are these generation ships, and should we think about creating them?
What Are Multi-Generational Ships?
As their name suggests, these ships are massive constructs designed to house multiple generations of humans, as well as survival necessities. Without faster-than-light propulsion, reaching a distant planet or solar system will take hundreds of years. The ship must be self-sustaining, providing oxygen, food, water, light and gravity throughout the journey. What sort of challenges should these intrepid interstellar humans expect to face during their trip?
Onboard Energy Expenditure
Now, we’re not talking about the energy it takes to keep the ship running — that’s a topic for another article. Instead, we’re referring to the energy you spend just surviving every day, also known as your basal metabolic rate.
Assuming you’re not dealing with the challenge of living in microgravity, generation ships will still need to create enough food to support a population of at least 500 souls for the decades or centuries it will take to reach another habitable planet. This task becomes even more difficult when you take into account physical activity and physically demanding jobs. Many of the careers on a generation ship — from farming to ship maintenance — will require additional food resources to provide enough calories to sustain the population.
People are inherently omnivorous — we get our nutrition from a combination of meat and plant life. In a generation ship, that means you’ll need enough space to grow food and raise livestock for an extended period. Food production gets tricky when your growing area is so limited. It’s easy to deplete the nutrients in the soil, preventing your next harvest from yielding as much or any edible food. You also need enough room to raise fish, cattle, pigs or chickens — and an adequate ventilation system to keep the methane they release from contaminating the ship’s atmosphere.
That, of course, assumes we’re going to be relying on terrestrial farming techniques and Earth-based livestock on a generation ship.
Space Farming Techniques
Hydroponics, or growing edible food in a water-based nutrient solution, and aeroponics — growing food in a misty, nutrient-rich air solution — might offer some alternatives. Astronauts on the International Space Station have been growing their food in an onboard hydroponic garden since 2002. Aeroponics is more viable for root vegetables that might not thrive underwater in a hydroponic garden.
Are We Ready?
So, should we be building generation ships to finally turn us into an interstellar species? Yes, but our technology isn’t quite there yet. We have a lot of challenges to overcome before we’ll be ready to send generations of humans on a one-way trip to the stars.