China News Service, Wenchang, July 23, title: "Fat Five" successfully launched the Tianwen-1 probe, China takes the first step in planetary exploration

　　Author Guo Chaokai

　　On July 23, accompanied by a deafening roar, the Long March 5 Yaosi carrier rocket was launched at the Wenchang Space Launch Site in China. After more than 2,000 seconds of flight, it successfully carried China’s first Mars exploration mission to the Tianwen-1 probe. It was sent to the predetermined orbit and the launch mission was a complete success. This mission is the first practical launch of the Long March 5 rocket, with many highlights.

The picture shows the Long March 5 Yaosi rocket ignited into space at the Wenchang Space Launch Site in China. Photo by Luo Yunfei

Highlight 1: The fastest speed to fly out of China's launch vehicle

　　The Long March 5 launch vehicle was developed by the China Academy of Launch Vehicle Technology affiliated to China Aerospace Science and Technology Corporation. It is also the rocket with the largest carrying capacity in China and is affectionately called the "Fat Five."

　　According to the requirements of the launch mission, the Long March 5 Yaosi rocket accelerated the Tuojutianwen-1 probe to a speed exceeding 11.2 kilometers per second, and then completed the separation, directly sent the probe into the ground fire transfer orbit, and started to run to Mars. journey of. When the speed of the spacecraft reaches the second cosmic velocity of 11.2 kilometers per second, it can completely get rid of the gravity of the earth and go to other planets or asteroids in the solar system. Therefore, the second cosmic velocity is also called the "escape velocity" .

　　"The launch of the Mars probe is the first time that the Long March 5 rocket has reached and surpassed the second cosmic speed, and has flown out of the fastest speed of a Chinese launch vehicle." Li Li, chief designer of the Long March 5 rocket, China Academy of Launch Vehicle Technology Dong said.

The picture shows the Long March 5 Yaosi rocket ignited into space at the Wenchang Space Launch Site in China. Photo by Luo Yunfei

Highlight 2: The first practical launch mission of the Long March 5 rocket

　　The Long March 5 launch vehicle is a new generation of high-thrust liquid launch vehicle in China. It adopts a "two-and-a-half-stage" configuration. The core stage of the rocket has a diameter of 5 meters and is bundled with four boosters with a diameter of 3.35 meters. All of them use liquid hydrogen and liquid oxygen. , Kerosene and other non-toxic and pollution-free propellants. The rocket has a total length of nearly 57 meters, a take-off weight of about 870 tons, a take-off thrust of more than 1,000 tons, and a geosynchronous transfer orbit (GTO) carrying capacity of up to 14 tons.

　　Previously, the Long March 5 Yao-3 rocket and the Long March 5B Yao-1 rocket were successfully launched continuously, marking that the key technical bottlenecks of the Long March 5 rockets have been completely overcome. The correctness and coordination of the rocket systems have been fully verified, and the rockets are reliable. The level of sexuality is further improved. Wang Jue, commander-in-chief of the Long March 5 rocket of the China Academy of Launch Vehicle Technology, said: "The implementation of the applied launch mission means that the Long March 5 rocket has officially begun to'service'."

At 12:41 on July 23, 2020, the Long March 5 Yaosi carrier rocket lifted my country's first Mars exploration mission "Tianwen-1" probe and ignited at the Wenchang Space Launch Site in China. About 2167 seconds after the rocket flew, it successfully sent the Tianwen-1 probe into a predetermined orbit, and started a Mars exploration journey, taking the first step in China's planetary exploration. Photo by Guo Wenbin

Highlight 3: Create a new record for the number of rocket launch orbit designs

　　Since the relative positions of the earth and Mars are constantly changing, launching a Mars probe is equivalent to hitting a "moving target." In order to allow the Mars rover to orbit more accurately, the development team carried out a refined "narrow window multi-orbit" design, subdividing the 30-minute launch window per day into three 10-minute windows corresponding to three launch orbits. A total of 42 launch orbits were designed during the 14-day window, which is unique in the history of China's aerospace launch. It created a new record for the number of single launch orbits and realized automatic switching of launch orbits for the first time.

　　This is the first engineering application mission of the Long March 5 series of carrier rockets and the second launch mission this year. While starting China's first planetary exploration journey, the number of consecutive successful Long March 5 series of rockets has been refreshed to three times.

At 12:41 on July 23, 2020, the Long March 5 Yaosi carrier rocket lifted my country's first Mars exploration mission "Tianwen-1" probe and ignited at the Wenchang Space Launch Site in China. Photo by Guo Wenbin

Highlight 4: The second launch of Long March 5 rockets in 80 days

　　On May 5 this year, the Long March 5B rocket, which belongs to the same series as the Long March 5 rocket, successfully flew for the first time, achieving the first victory of the Chinese space station stage mission. Completing two launch missions in two and a half months is extremely challenging for the Long March 5 rocket, which places high requirements on product development, final assembly testing, technical management, and launch support. The complete success of this launch means that the Long March 5 rocket has taken a solid step towards a "high-density" launch.

　　"The Long March of China's aerospace is always on the way. While participating in the construction of various major aerospace projects, the Long March 5 rocket will also provide technological accumulation for the development of heavy launch vehicles, laying a solid foundation for the leap-forward development of launch vehicles, and will provide stronger support. China is moving from a big aerospace power to a powerful aerospace power," said Wang Xiaojun, president of the China Academy of Launch Vehicle Technology.

The Tianwen-1 probe will fly in the ground-fire transfer orbit for about 7 months and arrive near Mars, complete the Mars capture by "braking", enter the ring-fire orbit, and choose the opportunity to carry out landing, patrol and other missions for scientific Mars exploration. Photo by Guo Wenbin

Highlight 5: Create a new record for the weight of China's deep space probe

　　The Tianwen-1 probe launched this time weighs about 5 tons. It consists of two parts: the orbiter and the landing patrol. It is more than one ton heavier than the Chang'e-4 lunar probe. It is currently the heaviest deep space probe launched by China. . From a global perspective, there are only a handful of Mars rover reaching this weight.

　　In this regard, Li Minghua, secretary of the Party Committee of the China Academy of Launch Vehicle Technology and the first commander-in-chief of the Long March 5 rocket, said: "With the strong carrying capacity of the Long March 5 rocket, China’s planetary exploration journey will stand on a new starting point, and achieve the goal through one launch. The three goals of Mars' orbiting, landing, and patrol. This is a mission with a high starting point and full of gold content. It will make China's deep space exploration step from the moon to the planet, officially opening the era of planetary exploration." (End)