the goal of p>SpaceX is to help people build a city that can accommodate one million people on mars, but what do these people do for a living? (Photo: SpaceX)

How can we feed one million people on Mars? A new study has found that artificial meat, pipeline crops and cricket farms may solve this problem for us.

When it comes to the manned mission to mars program, NASA usually sets a round trip plan that will only make a short stop on the surface of Mars. However, commercial space companies have the goal of exploring outer space, and SpaceX's specific goal is to establish a human colony on Mars.

For the long-term life on Mars, it is unrealistic to rely on the earth's supply spacecraft. The most practical strategy is to rely on the existing resources on Mars. Researchers have determined that human beings need five major consumable resources to survive on Mars, including energy, water, oxygen, building materials and food, and the first four resources may be very rich on Mars.

For example, we have solar energy, and there may be nuclear fission reactors, which can help provide energy for future Martians. Ice and water-bearing minerals on Mars are the sources of water, carbon dioxide can be converted into oxygen, and Martian soil can be easily made into bricks for building materials.

But in contrast, there is no natural food on Mars, and it is very difficult to use equipment (such as a simple chemical reactor) to make Martian raw materials into food, the researchers said.

Keith Cannon, a planetary scientist in university of central florida, Orlando, the main author of the research report, said in an interview: "Food is probably the most difficult thing to make locally on Mars. If you want to be self-sufficient, you can't rely entirely on imports."

Faced with this challenge, scientists want to know how to achieve this radical goal and produce enough food for 1 million people on Mars.

Cannon said: "We have cooperated with many people who want to grow plants in our simulated Martian soil, which shows us what research is being done in the scientific community in producing food for future human landing on the moon or mission to mars. As it turns out, these studies mainly focus on very low-calorie vegetables, and they don't take into account the latest innovations that replace protein sources. We raised the question: What does it take to feed a city with a population of one million as envisaged by SpaceX, aside from the short-term mission of NASA? "

researchers point out that it is unrealistic to raise farm animals on Mars to obtain dairy products and meat in the short term, because transporting these animals to Mars will face many challenges. But at the same time, they also noticed that most people don't want to be completely vegetarian. Therefore, they think that cultivating meat in insect farms and laboratories will be the solution to this problem.

The researchers say that insect farms are very suitable for making Mars food, because they can provide a lot of calories per unit of land with relatively little water and feed. At the same time, they also point out that crickets are one of the most promising examples of eating insects, and cricket flour may be included in many different recipes.

Cannon said, "If people can overcome psychological factors, then insects are the solution to this problem."

Researchers say that for those who don't like insects, "cell agriculture"-that is, food made from cells cultured in the laboratory-can help people on Mars eat some foods they are more familiar with. Now, researchers say, everything is possible from algae to meat and fish, to cow-free milk and chicken-free eggs. After investors invested a lot of money to improve this technology, the cost of an artificial meat pie has dropped from $325, to $11 in two years.

When it comes to crops, researchers say that artistic illustrations of Martian settlements usually have greenhouses, but these greenhouses may not be practical. Because Mars is too far away from the sun, even at the equator with the most sunshine, the amount of light received by plants is similar to that they received in Alaska. In addition, although greenhouses are made of transparent glass windows, they usually absorb 5-7% of the light when they are on the earth, but on Mars, these glasses may only absorb more light, because the atmosphere of Mars is colder and thinner, so the greenhouse of Mars needs stronger materials to support an internal heating and pressurizing environment.

The researchers say that planting plants on Mars may require tunnels with high-intensity LED lighting, as well as collecting and transmitting sunlight through optical fiber cables. They said that it is also possible to use hydroponics or air culture systems for soilless farming, but these strategies will require trays, pumps and water tanks, so we need to transport more materials to Mars. In addition, soil-based agriculture may be more resistant to diseases, but the researchers added that only after a lot of research and treatment can inorganic soil on Mars be transformed into living soil that can support plant growth.

Previous studies have shown that many crops may be particularly useful for Martian colonists, such as wheat, corn, soybeans, peanuts and sweet potatoes. Genetic modification technology can also make crops help Martian people in many ways-for example, consuming more carbon dioxide and increasing production.

cannon said: "Up to now, almost all the research has focused on planting plants to feed astronauts, but plants will take up a lot of space. On another planet, this means building more large indoor factories that need pressure, heating and lighting. If you want to feed a large group of people on another planet, you must abandon the idea of growing watery vegetables and think about the large amount of energy, water and raw materials needed to produce enough calories. "

in order to understand what it may take to feed a Martian city with a population of one million, the researchers simulated a crowd model, including both immigrants from the earth and people born on Mars, with a birth rate of 25% per year (this is a typical birth rate in developed countries). All in all, they assume that in a century, humans need to carry out 6,9 spacecraft missions to send about 1 million immigrants to Mars, of which 34, were born on Mars.

The scientists calculated the calories needed by each person and simulated the land utilization by dietary conditions including wheat, corn, sweet potatoes, crickets and laboratory-raised chicken. They found that a Mars colony with a population of one million could be self-sufficient in food within 1 years by relying on a vertical pipeline about 9, miles (14,5 kilometers) long and 12 feet (3.6 meters) wide.

However, during this period, these colonists will need about 54, flights to import a lot of food. Scientists point out that there are actually many ways to significantly reduce the amount of imported food, such as increasing the speed of farm construction on Mars.

Cannon said: "These studies have been questioned by a very common people. People think that this is the plot of science fiction-it will take decades for a manned mission to Mars to be realized, so why bother to study this now? In fact, anyone who holds this view needs to take a serious look at what SpaceX is doing-they are already testing the prototype of the Mars launch vehicle. "

He added that it was time to "find out how to achieve this goal".

Researchers say that research on how to feed Martian colonists can also help feed people on earth.

Cannon said: "The restrictions brought by the cold and thin atmosphere of Mars will force you to produce food in a more sustainable and ethical way than the existing factory farming methods on earth. Therefore, converting our current eating habits into' Martian eating habits' can also help our own planet. " To this end, scientists have created a website, http://eatlikeamartian.org, which provides some relevant information.

cannon and Daniel Britt of university of central florida, a senior author of the research report, introduced their findings in detail in the online edition of New Space magazine on August 3th.