A little over ten years ago, China began exploring the moon as it sent a space ship named after an ancient moon goddess to the moon. Thanks to the Chang & # 39; e-1 spacecraft, China was the third country in the world after the former Soviet Union and the US to have its own moon maps.
This week, China's latest moon exploration mission is expected to make history for humans Space exploration – for the first time ever, will land with a spaceship on the other side of the moon. China's Chang & # 4; e-4 and Rover launched local time early on December 8 and are expected to land each day. China's space agency said weekend that the Rover was landing just 1
If it succeeds, it will do so A significant achievement for China's space program in view of its technical complexity, from landing itself to maintaining communication with the spacecraft.
"This [would be] was the first time that the Chinese space program has done anything other than anything land has done before," said Brian Harvey, author of China In Space a story of Chinese space program of 2013. "So far, China has largely achieved the achievements of the USSR and the USSR – not to do so – but because they are necessary steps in building a space program. This is pretty new. "
For science, the mission could finally bring the secrets of the hidden side of the moon out of the shadows. We know the following about the challenges of the upcoming landing.
A landing site named after a "Martian"
In 2016, a research paper from a research institute under the Chinese National Space Agency investigated five possible landing sites, wrote Philp Stooke, professor of physics and astronomy at the Western University of Canada. which deals with the mapping of planets. These locations included the areas of influence Oriental, Austral, Moscovinse, Apollo and Ingenii. These were excluded because they would either be too hot or too cold for the spaceship because of their latitude, Stooke said in an email to Quartz.
By 2017, according to Stooke, showed a slide that Chinese scientists had presented in the German Space Center The landing pad would probably be the relatively smooth Von Kármán crater, a 186-kilometer-wide region, named after Theodore Von Kármán, a Hungarian-American aerodynamics Expert contributing to NASA's Jet Propulsion Laboratory and its first director. Von Kármán is one of the five scientists who were referred to as "the Martians" for their significant scientific achievements in the 20th century.
The Von Kármán region is located in an even larger impact crater called the South Pole Aitken Basin (SPA). This is 2,500 kilometers wide – it is so large that it is likely that its effects have lifted parts of the Moon's mantle. According to Zou Yongliao (link in Chinese), director of the Moon and Space Exploration Division of the Chinese Academy of Sciences, the basin is thought to have formed about 4 billion years ago. The pelvic dating (pdf) is an important goal of lunar research to detect if the moon was subject to a catastrophic event and possibly to provide clues as to what was going on in the solar system at that time.
Waiting for Light
Chang & # 39; e-4 had its planned orbit for landing on Sunday (December 30) according to China Academy of Space Technology (CAST) (link in Chinese), the state-owned manufacturer of the spacecraft , It has also made several successful "phone calls" with the relay satellite Queqiao, which according to CAST suggests a good signal connection (link in Chinese). Queqiao was launched in June to build a bridge between the spaceship and the Earth, as direct communication between the two is not possible. The relay satellite has an irregular circular orbit that simultaneously keeps the earth and the distance in view. 19659002] Chang & # 39; e-4 waits for the perfect landing timing – sunlight must be in the landing area as it is solar powered – and it also requires precise communication with the relay satellite as it navigates through the rugged, distant side , 19659002] When Chang'e-4 braked near the moon on December 9th (left link in Chinese) to reach the Moon orbit, it was just in the landing area. According to Sun Zezhou (Chinese Link), chief designer of Chang & # 39; e-4 at CAST.
This window had to stay in the lunar orbit over the targeted landing site and wait for sunlight to return to the other side. Around the 3rd Beijing time, CAST arrives. After 26 Days (Connection in Chinese) [C9]
Chang & # 39; e-4 must go through several steps Before putting on, they start about 15 km above the ground where she is now. He will adjust the speed at a height of 8 km and his position at a height of 6 km. He floats for a while at a height of 100 meters and uses his instrument to avoid dangers to calibrate his last landing place in the last 30 meters According to a demonstration by CAST.
The chance of a safe landing is only 50:50, . The author of the author Harvey told Quarz, with risks in several places, from speed control to communication with the relay satellite for problems with the rover's radar sounding and hazard avoidance capabilities. China has conducted landing, radar and hazard avoidance tests in the western desert of Xinjiang, which Harvey's research has identified as the best available analogue to the Moon.
"Scientists and engineers exhaustively investigated the landing area to find a shallow area with as few rocks, craters, or slopes as possible. The map of the intended landing site was then programmed into the computer CE-4 [Chang’e-4] so that the radar soundings on the arrival there are matched with the map and the guidance system puts them in the right place, "Harvey told Quartz. "The Americans use a similar system for their Mars landings. Theoretically it may sound easy, but it is done from a great distance without the possibility of human intervention.
Agriculture on the Moon, Listening to the Universe
Just like geologists on Earth, scientists can better understand our knowledge of satellite by examining its mantle, the layer between the core and the crust, to understand how it originated and what chemical elements helped him. Humans have so far brought around 382 kilograms of items, including lunar rocks and core samples, during the six moon explorations of the Apollo missions that the US completed between 1969 and 1972. But none came from the other side. 19659002] The opposite side had fewer "mares" – dark colored parts that the ancient astronomers used for seas – and a larger visible crater cover than the near side. Scientists still have not understood what has led to the differences, but Chang & e4 could help change that.
The mission carries instruments developed by scientists in Germany, the Netherlands and Sweden to study the Moon and the Universe when the Lander is successful in landing.
German scientists from the University of Kiel contributed to the development of the Mondlander neutrons and dosimetry, which is on the lander and will measure the lunar radiation values among other things. Swedish scientists from the Institute of Space Physics and the National Space Science Center have developed a Neutral Advanced Small Analyzer, which will be on the way with the rover to study how solar wind interacts with the lunar surface. On the relay satellite of Queqiao, a radio antenna designed by researchers from the Dutch Radboud University will receive signals that will reveal the origins of the universe.
Chinese scientists have also planted seeds of potatoes and Arabidopsis, a small flowering plant that belongs to the USA Mustard Family – along with silkworm cocoons on the spaceship to test life on the moon.
If China succeeds, it will strengthen its confidence in the Chang'e-5 mission, which is scheduled for the end of 2019, Harvey said. China will use Chang's e-5 to collect and return samples on the near side of the moon.
The ultimate goal for China, according to officials, is to bring people to the moon, a milestone that has been reached by the US for more than half a century. China could achieve this in 2030, Harvey added, adding: "While Apollo conducted expeditions of one to three days," flags and footprints, "China's first landing will take a month and a base will not be built long after."  Are you looking for more detailed coverage? Sign up to become a member, and learn more about the history of lunar research.