Use wechat to scan QR code < / P > < p > to share with friends and circle of friends < / P > < p > just now, China's first < a target = "_ blank" href=" https://news.163.com/news/search?keyword=%E7%81%AB%E6%98%9F "> Mars < / a > mission tianwen-1 < a target ="_ blank" href=" https://news.163.com/news/search?keyword=%E6%8E%A2%E6%B5%8B%E5%99%A8 "> the probe has successfully carried out plane maneuver to capture the far fire point in orbit, completed orbit adjustment, and changed its flight route around Mars from" horizontal "to" vertical ", so as to photograph the poles of Mars and complete the global remote sensing imaging mission of Mars. In the future, tianwen-1 will enter Mars docking orbit through several orbit adjustments. < p > < p > < b > related reading: < / b > < / P > < p > < / P > < p > < b > the capture process of tianwen-1 by Mars: the probe vibrates slightly and the surface of Mars is clearly visible < / b > < / P > < p > Feng Hua, the client of people's daily On February 12, 2021, on the occasion of the Chinese new year, the National Space Administration released images of the Mars capture process of China's first Mars exploration mission, tianwen-1. < / P > < p > images of the solar wing surveillance camera < / P > < p > the surveillance camera completely recorded the process of Mars entering and leaving the field of vision, the slight vibration of the probe after the ignition of the engine, and the process of the probe flying from Mars during the day to the night. The solar wing, the directional antenna, the atmosphere and the surface morphology of Mars are clearly visible. Tianwen-1 sends new year's blessing from the distant Mars. < / P > < p > < / P > < p > directional antenna surveillance camera < / P > < p > < / P > < p > < b > from capture to fire, What will tianwen-1 do in the next few months? < / b > < / P > < p > CCTV news at 19:52 on February 10, 2021, China's first Mars exploration mission, tianwen-1, implemented the near fire capture brake, successfully entered the large elliptical ring fire orbit, becoming China's first man-made Mars satellite, and successfully achieved the goal of "circling, landing and patrolling". < / P > < p > "tianwen-1" flight phase diagram (source: National Space Administration) < / P > < p > since its successful launch on July 23, 2020, "tianwen-1" has flown 202 days, with a flight mileage of about 475 million kilometers and a distance of about 192 million kilometers from the earth. After orbiting Mars, tianwen-1 plans to land on Mars from May to June 2021 to carry out patrol exploration. < p > < p > "tianwen-1" flight image (source: NASA) < / P > < p > [dot · Dao] Yang Yuguang, vice chairman of the Space Transportation Committee of the International Astronautical Federation and researcher of casic-2, was invited to interpret the preparation work before "tianwen-1" and the difficulties in the follow-up "fire" process. < p > < p > Yang Yuguang, vice chairman of the Space Transportation Committee of the International Astronautical Federation and researcher of the second Academy of China Aerospace Science and industry group < / P > < p > < strong style = "box sizing: inherit; font style: normal;" > 1? < / strong > < / P > < p > < strong style = "box sizing: inherit; font style: normal;" > Yang Yuguang: < / strong > < / P > < p > < strong style = "box sizing: inherit; font style: normal;" > similarities: < / strong > "there is only one chance of success.". spacecraft < / a > approach similar to < a target ="_ blank" href=" https://news.163.com/news/search?keyword=%E6%9C%88%E7%90%83 "> celestial bodies such as the moon < / a > and Mars are affected by gravity, and their speed is accelerating. If they don't brake at the right time, the spacecraft will get rid of the constraints of celestial gravity and can't complete the" capture ". < / P > < p > < strong style = "box sizing: inherit; font style: normal;" > differences: < / strong > < / P > < p > - first of all, Mars is bigger than the moon and has greater gravity, so it needs more power and consumes more propellant to brake near fire. < / P > < p > - secondly, near fire braking requires higher spacecraft autonomy. The average distance between the earth and the moon is 380000 km, and the communication delay is about one second. At present, the distance between the earth and the fire is nearly 200 million km, and the communication delay is about 10 minutes. Therefore, the braking command of "tianwen-1" was advanced and executed independently. This is the first time in China's space history. < / P > < p > "tianwen-1" renderings ((source: No.8 Institute of Aerospace Science and Technology Group) < / P > < p > < strong style = "box sizing: inherit; font style: normal;" > 2. What does "tianwen-1" do in the months from "capture" to "fire"? < / strong > < / P > < p > < strong style = "box sizing: inherit; font style: normal;" > Yang Yuguang: < / strong > first of all, we need to implement further track change. Let "tianwen-1" change from the current low inclination large ellipse orbit to the "polar orbit" with an inclination close to 90 degrees, and let "tianwen-1" pass through the north and south poles in every circle of its flight around Mars, so as to realize the exploration coverage of various regions of Mars. The second step is to carry out landing preparation, including using the camera carried by orbiter to explore the utopian plain, which is the preset landing site, so as to prepare for the combination of lander and Rover to enter the Martian atmosphere. < / P > < p > after determining the "fire fall" time, "tianwen-1" needs to descend the altitude first. After the combination of the lander and the rover is separated, the orbiter will raise the altitude and turn into the relay orbit to build an information relay transmission channel between the rover and the earth. < / P > < p > "tianwen-1" renderings ((source: No.8 Institute of Aerospace Science and Technology Group) < / P > < p > < strong style = "box sizing: inherit; font style: normal;" > 3. Why does the industry use "seven minutes of terror" to describe the "fire falling" process? < / strong > < / P > < p > < strong style = "box sizing: inherit; font style: normal;" > Yang Yuguang: < / strong > landing on the surface of Mars is more complicated than landing on the surface of the earth or the moon. The atmospheric pressure on Mars is only 0.6% - 0.7% of that on earth. In the process of spacecraft entering Mars, on the one hand, it can not rely on the atmosphere to reduce to a safe speed, and at the same time, it must consider the thermal impact caused by air friction. < / P > < p > "tianwen-1" implemented "fire fall" in three ways: heat shield, parachute and thrust reverser engine. In the first stage, we rely on the heat shield to prevent the heat generated by friction with the Martian atmosphere from damaging the detector while decelerating. After decelerating to a certain speed, we launch the parachute. After further decelerating, we timely abandon the heat shield and parachute and start the thrust reverser engine. The three means must be perfectly and seamlessly connected. Among the three missions of Mars exploration, the most difficult one is the process of Mars exploration. < / P > < p > "tianwen-1" landing Rover enters Mars atmosphere
2023-03-22 10:04:28