Human Habitation on Mars

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　For thousands of years, people have looked up at the night sky and wondered, “What’s up there? Will human beings be able to go there someday?”
　More than a hundred years ago, astronomers first looked at Mars, a bright red star, through telescopes. They noticed many lines on the surface. The lines were thought to be canals, perhaps made by some kind of intelligent beings. Some people imagined that Martians looked like an octopus. They thought they must have big heads and be super-intelligent. They must also have long, thin legs and arms due to the weak gravity on Mars. Until just a few decades ago, some people still believed that Martians looked like that.
　About fifty years ago, a spacecraft landed on Mars for the first time and sent photographs back to Earth. People were anxious to see what the planet looked like and what, if anything, lived there.

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　The photos didn’t show any canals or signs of life, however. Instead, they just showed a reddish-brown desert that stretched to the horizon.
　Even so, several countries have continued to send probes to Mars. These probes have made a number of important discoveries. For example, today we know that there was once a large amount of water on this dry planet. There is a possibility that there are still lakes of unfrozen water below the planet’s surface. Some complex organic material was also found in a dirt sample, which suggests there may have been, or may still be, some form of life on Mars.
　At present, two American rovers, Curiosity and Perseverance, are in operation on the Red Planet. As their names imply, the curiosity and perseverance of human beings have led to remarkable discoveries. They now drive scientists to make further explorations. With more projects planned for the future, astronauts may be able to land on Mars within the next ten to twenty years.

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　In order to learn more about Mars and the origins of life, astronauts will have to stay on the planet for long periods. But will it be possible for humans to live on Mars?
　One of the biggest challenges will be to transport materials to Mars to build living facilities there. Transporting heavy construction materials from Earth will be far too difficult and expensive. So some architects, including a Japanese couple, came up with the idea to use the large supplies of underground water on Mars. If the water is brought up to the very cold surface, it will quickly freeze and become solid ice. The astronauts can then use the ice to build houses. In this way, only items such as drilling equipment and 3D printers will be necessary to shape buildings from the ice.
　In 2015, this idea won NASA’s contest for the best way to construct buildings on Mars.

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　Why do countries spend so much time and money on space exploration? It is not just out of curiosity about outer space or in preparation for the distant future. In fact, space research can benefit people in unexpected ways.
　Here is a good example from Venus, another nearby planet. The exploration of Venus has revealed that most of its atmosphere is carbon dioxide and that temperatures on the planet average 500 degrees Celsius. This has given researchers some clues that have helped them understand the causes of global warming on Earth.
　Inventions like artificial hearts and cloud-computing technology are also spin-offs from space research. There is a saying that goes, “Necessity is the mother of invention.” But perhaps the real mother of invention is human curiosity and imagination. No one knows what practical contributions space exploration on Mars and beyond can make to our future. Maybe some of you will be the first real “Martians” and will make your own remarkable discoveries.