China's Deep Space Exploration "Aiming" Asteroid

The State Council Information Office recently released a white paper entitled "China's Space Flight of 2016". It also mentioned asteroid detection when describing the main tasks of deep space exploration in the next five years.

Ji Jianghui, a member of the China Deep Space Exploration Scientific Targeting Experts Committee and a researcher at the Zijin Mountain Observatory of the Chinese Academy of Sciences, said that the expert group has demonstrated China's major scientific goals for deep space exploration in the next 20 years. It is currently basically determined that the Mars exploration program is based on asteroid detection. , followed by Jupiter and the European guardian system.

Goal: Choose three special asteroids

Asteroids generally refer to smaller rocks or metal objects orbiting the sun. Most asteroids are located in the main zone between Mars and Jupiter orbits. Due to their low mass, most asteroids are irregular in shape. These small, non-atmospheric asteroids may contain important clues to the life of the Earth and the origin of the water body, as well as the original information of the early solar system. The study of asteroids has important scientific value. Some asteroid orbits are close to or intersect with Earth's orbit, and there is a possibility of colliding with the Earth. This poses a potential danger to Earth and human security.

“The experts’ plan is to launch an asteroid space probe and carry out fly-by, fly-by, and fly-adhesion detections on three near-Earth asteroids. Attachment is to land on the surface of an asteroid and perform in-situ sampling analysis.” Ji Jiang Emblem said.

Currently, only the United States and Japan have landed on asteroids in the world. Japan's ostrich-1 detector landed on the Aikawa Asteroid and returned it.

"In 2017, China will launch the Chang'e ‧ s squadron. If Cangwu No. 5 can successfully return from the moon, it means that China has the ability to sample and return from other celestial bodies. In the future, China may sample and return from asteroids like Japan. On the laboratory to analyze the samples retrieved." Qi Jianghui said.

Ji Jianghui said that the preferred target for exploration is the near-Earth asteroid that poses a threat to the Earth and evaluates their probability of hitting the Earth. Second, it studies the formation and evolution of asteroids to study the origin and evolution of the solar system; The origin of water.

He introduced that Chinese scientists are planning to select three very special near-Earth asteroids as targets for detection. They are currently envisioning a companion flight of the Apophis asteroid, carrying out associated flight and attachment detection of the 1996FG3 asteroid, and based on the launch of the detector. The window selects a near-Earth asteroid for overflight detection. The entire exploration mission lasted about 6 years.

Alert: Dealing with Potential Threats from Space

The Apophis asteroid was discovered in 2004 and has a maximum diameter of about 394 meters and a width of more than two football fields. Experts estimate that Apophis will pass the earth on April 13th, 2029, more than 30,000 kilometers from the surface of the earth, much closer to the Moon than the Earth, and will be visible to the naked eye. As its orbit is changed by gravity, it will return to earth in 2036.

"Apophis" is the god of destruction in Egyptian mythology. It was named because scientists thought that this asteroid was a great threat to the earth. There are more than 100 research teams in the world to study it. However, scientists currently estimate that it has a very low probability of hitting the Earth.

Although it is not necessary to worry about Apophis for the time being, scientists estimate that there are 300,000 near-Earth objects with a diameter of more than 40 meters in the vicinity of the Earth. Currently only about 3% are found. This has led the international community to pay more attention to the threat of the near-Earth asteroids to the Earth and human survival. In December 2013, the UN General Assembly approved the establishment of an international asteroid warning network.

In late January 2017, as a member of the Early Warning Network, three near-earth asteroids were discovered at the Purple Earth Observatory near-earth astronomical telescope: 2017 BK3, 2017 BM3, 2017 BL3, 2017 BL3 is a potentially threatening near-Earth asteroid .

The US White House Science and Technology Policy Office recently released the National Strategy for the Prevention of Near-Earth Objects, pointing out that NEOs as a potential threat may cause serious disasters to the global environment, economy, and geopolitics. On February 15, 2013, the Chelyabinsk meteorite incident in Russia resulted in 1200 injuries and nearly 3,000 buildings were damaged.

Ji Jianghui said that in the face of the collision threat of near-Earth objects, it is necessary not only to build a special telescope on the ground to form a monitoring and early warning network, but also to conduct a comprehensive survey of space-based near-Earth asteroids, and a detailed close-range survey of launching asteroid detectors. Learn about its physical properties, internal structure and composition.

He said that China's launch of asteroid deep space exploration will help better understand the basic characteristics of NEOs and facilitate the adoption of effective countermeasures in the future to prevent, mitigate, or eliminate collision threats.

Quest: Or will discover the mysteries of the origin of life

Scientists believe that the 1996 FG3 asteroid may discover the secret of the origin of life on Earth.

Ji Jianghui said that there are two theories about the origin of life on Earth. One is that life is bred on the Earth itself and the other is from outer space. Many of the meteorites the scientists have found contain organic matter and are believed to be related to the origin of life. Water has also been found on many asteroids. Some scientists believe that water on Earth may come from asteroids or comets.

"Why is the 1996FG3 asteroid considered to be related to life? Because scientists have done a lot of astronomical observations on the ground. It has been discovered through spectroscopic analysis that it is a carbon asteroid and may contain organic groups needed for the origin of life. Points.” Qi Jianghui said.

He said carbon asteroids have a lot of main bands between Mars and Jupiter, but they are rare in near-Earth asteroids. These asteroids may be disturbed by the gravitational perturbations of the large planets and leave the main zone, and they receive kinetic energy due to uneven thermal radiation in all directions, thus pulling them closer to the Earth.

Ji Jianghui introduced that the Purple Mountain Observatory and relevant domestic units have cooperated to complete the development of the prototype of the asteroid sampling integration device, which provides a powerful guarantee for the in situ sampling of asteroids in China.

Journey: Flying over "God of War"

In fact, China has already overflighted an asteroid.

It resembles a ginger, and it resembles a bizarre peanut. It is an asteroid named after the god of war in the western mythology, Tuttis. Tuttis is a near-Earth asteroid that poses a potential threat to the Earth. It is close to the Earth every four years before 2012.

On December 13, 2012, China’s second lunar probe Chang’e 2 successfully completed the mission for the lunar exploration and the day-to-ground L2 test mission, and it was in a deep space about 7 million kilometers away from Earth, at a rate of 10 thousand per second. The relative speed of the meter flew past the Tutanites asteroid, and the closest distance to the "God of War" was about 770 meters.

This is the first time that China has achieved the overflying detection of asteroids, and it is the first time in the world that it has realized the detection of "God of War". The probe photographed the optical image of the asteroid and showed its surface features clearly before the world for the first time.

Although astronomers currently observe a lot of asteroids, there are only a dozen or so planets that detect and photograph the space. Ji Jianghui's team and collaborators carried out in-depth research on Tuttis. A series of articles were published in the "Science Report" and "The Royal Astronomical Society Monthly" published in "Nature" Publishing Group.

Scientists discovered that Tuttis consists of a "head" on the smaller end and a "body" on the larger end. According to the image estimate, it is about 4750 meters long and about 1950 meters wide. The scientists also studied why it could "turn around" in space; it revealed that most of the gravel on its surface came from residual debris from the formation of the early Tutanes asteroid matrix. The age of the surface impact pit was estimated to be about 16 billion years.

(Original title: After planning to explore Mars, China has once again aimed at the space "Wanderers")