The safest place for humans on Mars, sheltering them from radiation, may be the lava tubes located in the basin of Hellas Planitia, at a depth of seven kilometers, where overhead people will be more Martian atmosphere.
There is absolutely no safe place for a base on Mars. But a team of researchers has determined where the best hiding place for future Martians is: a chain of lava tubes in the low-lying part of the Hellas Planitia impact basin.
Mars is unfriendly — it has a dry, dusty surface, lacks oxygen, and is bathed daily in the rays of solar radiation, which is a major problem for colonization. On Earth, we are shielded from radiation by a powerful magnetic shield, the magnetosphere.
The Hellas Planitia basin, by itself, has several advantages. NASA studies have shown that the most radioactive areas of Mars are its poles. But Hellas Planitia is closer to the equator. In addition, the impact basin is one of the lowest at 7,152 meters. This means that there will be a thicker layer of Mars’ atmosphere overhead. Researchers write that the bottom of the basin has 50 percent less radiation than Mars’ high-altitude regions – 342 μSv (microsievert) per day (sol) versus 547 μSv.
But this is still a lot to be considered a safe level of radiation (0.5 µSv per hour). That’s 25% more radiation exposure than astronauts on the ISS receive every day, where they spend only a few months, not years.
Exposure to a radiation dose of 342 μSv per day for many years, however, can pose serious risks to humans.
The maximum safe dose according to the U.S. Nuclear Regulatory Commission is 6,200 μSv per year. At 342 µSv per day, Mars explorers would cross the safe threshold in just 19 days.
Scientists have calculated that living in the Hellas lava tube would give people about 61.64 µSv per day. But even that dose isn’t safe. It’s true that tubes have other benefits for living. Fortify them, make them airtight, and you can keep them pressurized and heated, creating a livable environment.
The tubes would also protect against micrometeorites, temperature variations on the planet’s surface, and Martian dust. In addition, it will be possible to conduct excavations without leaving “home”.