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NASA’s Curiosity rover exploring Mars. Photo source: NASA. |
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[아시아경제 김봉수 기자] Recently, rovers from the United States and China have been working hard to determine the existence of life on Mars. In recent years, evidence of ancient seas and floods has also been found. However, so far, only the ‘circumstances’ have been confirmed, and conclusive evidence has not been secured. Even if they collect the samples they collect and bring them back to Earth for analysis, it is expected that it will be difficult to find evidence of the existence of life. Why? The answer is cosmic radiation and ‘excavator’.
◇Spaceship destroys evidence of life
According to the National Aeronautics and Space Administration (NASA) on the 1st, the NASA Goddard Space Flight Center research team recently created an environment similar to the surface of Mars and studied it. got off The research team published this paper in the international academic journal ‘Astrobiology’ published on June 24th.
NASA is trying to confirm the existence of ancient life by collecting rock and soil samples through rovers such as Perseverance, which landed on Mars in February last year. The substance we want to check the most is amino acids. Although it is produced by natural chemical reactions, it is because it is a component of proteins that make up life on Earth. The problem is that, unlike Earth, which is protected by the atmosphere, high-energy cosmic rays pouring down on the surface of Mars break down substances such as amino acids. Cosmic rays, which are mostly composed of protons and helium ions, are created through stellar explosions such as the sun, and ionize and destroy all substances, including organic molecules, such as amino acids, while penetrating hard rocks and everywhere.
The research team found that the depth that a rover currently operating on Mars can dig for sample collection is only 2 inches (about 5 centimeters). I have come to the conclusion that a year is sufficient. The period of life on Mars is far too short compared to what is estimated to be billions of years ago. So, if Mars rovers are “lucky” to find evidence of life, they have no choice but to find and extract material from microcraters less than 1,000 years old that were created or ejected from them. The research team also confirmed that the addition of water and perchlorate accelerated the decomposition of amino acids in spacecraft. Accordingly, it was concluded that it is likely that it would be possible to dig at least 2m or more to find amino acids that are evidence of the existence of ancient life on Mars. In fact, scientists, including NASA, are trying to anticipate this and send a rover that can dig more than 2 meters to Mars. This is the ExoMars mission that the European Space Agency (ESA) was promoting with Russia and recently broke up with.
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Mars excavation concept. Picture source = NASA |
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◇Digging in a space that is more difficult than you think
Even if the Exomas mission is executed and a rover with a 2m drill arrives, it is unknown whether or not it will succeed. This is because ‘digging’ on a planet other than Earth is the most difficult task. The failure of NASA in January last year is a prime example. NASA planned to study the internal structure of the Martian crust by excavating at least 3 to 5 meters through an excavator, so-called ‘mole’, aboard the Mars lander Insight. The mole was a pile driver, that is, a perforator, made of a titanium tube with a length of 40 cm and a diameter of 2.7 cm. It is a method of inserting a tube into the soil surface and then digging a little deeper while tapping the hammer mounted inside. However, the hammering of moles, which started on February 29, 2019, did not move anymore after advancing 30 cm for the first month. The German Aerospace Center (DLR), which developed the equipment, made every effort for a year and a half, but finally gave up on January 9 of last year after attempting 500 hammering. The cause is believed to be the case when the soil is too soft or clumped together, or when it hits a hard rock, but no one knows the cause yet.
The same is true of the Curiosity rover, which went to Mars in 2012. Even though nuclear power cells, which are much stronger than solar cells, were used to run drills in about 20 places, the excavation depth was only 6.4 cm. It may be different if you take a large drill used on Earth, but it is impossible because it requires enormous cost and energy consumption.
The same goes for people who sell themselves. During the Apollo 15, 16, and 17 missions to the moon in the early 1970s, astronauts mobilized a 3-meter-long drill, but suffered hardships. It was because the surface had fine soil, but the inside was very hard. Apollo 15 drilled for three days, but only digged 1.6m. Apollo 16 was unable to work due to equipment failure. The last Apollo 17 astronauts succeeded in installing a heat flow detector that penetrated only 2.92 m. In addition, the Soviet Union’s Luna 24 (1976) and China’s Chang’e 5 (2020) used unmanned missions to drill a 2m hole to extract lunar rocks.
By Kim Bong-soo, staff reporter [email protected]
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