The cargo loading capacity of China’s cargo spacecraft exceeded 7 tons for the first time.

　　Xinhua News Agency, Wenchang, Hainan, May 10 th: Four highlights of the launch of Tianzhou-6

　　Xinhua News Agency "Xinhua Viewpoint" reporters Song Chen, Li Guoli and Chen Kaizi

　　The effective loading capacity of the whole ship’s materials has been expanded by 20%, and the strength of "carrying goods" has been upgraded; The Long March 7 carrier rocket and Tianzhou cargo spacecraft joined hands for six times, further shortening the test time and further improving the reliability of the process; We will focus on the fields of space life science and biotechnology, and carry out 29 scientific experiments and application experiments … …

　　On the evening of May 10th, China successfully launched the Tianzhou-6 cargo spacecraft with the Long March 7 carrier rocket at Wenchang Space Launch Site. This is the first launch of China’s manned space engineering mission in 2023, and it is also the first flight mission in the application and development stage of China’s space station. What is the upgrade of this "Tianzhou Express"? What are the highlights of the launch mission?

　　Aspect 1: A new batch of cargo spacecraft is "launched"

　　On May 5, the Tianzhou-5 cargo spacecraft was successfully evacuated from the space station assembly and transferred to the independent flight stage. Today, China Space Station has welcomed new partners.

　　The Tianzhou-6 cargo spacecraft launched this time undertakes the tasks of material support, on-orbit support and space science experiments for the space station. Compared with Tianzhou-4 and Tianzhou-5 cargo spacecraft launched during the overall construction stage of the space station, Tianzhou-6 cargo spacecraft has an "extraordinary" identity — — The first spacecraft launched in the application and development stage of China’s manned space station; The first ship of China’s improved cargo spacecraft; The first cargo spacecraft produced in batches from Tianzhou 6 to Tianzhou 11.

　　On May 7, the combination of Tianzhou-6 cargo spacecraft and Long March-7 remote-7 carrier rocket was ready for transshipment. Xinhua News Agency (photo by Qiu Lijun)

　　As the ground logistics replenishment spacecraft of the space station, Tianzhou cargo spacecraft adopts the pattern spectrum scheme, and designs three types of patterns to meet different cargo transportation needs: fully sealed cargo spacecraft, semi-sealed cargo spacecraft and fully open cargo spacecraft.

　　Up to now, the cargo ships Tianzhou-1 to Tianzhou-6 are all developed by the Fifth Academy of Aerospace Science and Technology Group, among which Tianzhou-6 is an improved fully sealed cargo ship, which has the largest cargo transportation capacity and the most comprehensive on-orbit support capacity in the world.

　　In order to meet the demand of intensive launch, the Fifth Academy of Aerospace Science and Technology Group implements the batch production mode in the production process of Tianzhou cargo spacecraft, that is, Tianzhou No.3 to Tianzhou No.5 are produced and developed in batches, and Tianzhou No.6 to Tianzhou No.11 are produced and developed in batches, so as to ensure that the appearance and function of the same batch are similar or similar.

　　Since Tianzhou-6, the technical team has systematically upgraded the cargo spacecraft for the follow-up tasks, such as greatly improving the cargo cabin and greatly enhancing the cargo transportation capacity of the sealed cabin, so that the materials provided to the astronauts can last longer.

　　Aspect 2: Upgrade the strength of "bringing goods"

　　Tianzhou cargo spacecraft undertakes the mission of replenishing the propellant consumption of the space station and transporting the living materials of astronauts, which plays a very important role in the logistics support of the space station. In this mission, the Tianzhou-6 cargo spacecraft carried 258 pieces (sets) of cargo, with a total weight of about 5.8 tons, including six astronauts’ in-orbit consumables, about 700 kilograms of supplementary propellant and a number of actual (test) loads.

　　Yin Rui, senior engineer of China Astronaut Center and deputy commander-in-chief of astronaut system, said that the living materials of astronauts carried this time mainly include clothing, food, drinking water, etc. Among them, the fresh fruit weighs 71kg, which is about twice the weight of the fruit carried by Tianzhou No.5, which can meet the needs of Shenzhou 15 and Shenzhou 16.

　　A cargo ship, its "cargo" strength — — The strength of cargo loading capacity is the criterion of its "hard core". Therefore, how to effectively improve the cargo loading capacity has become the focus of the development of Tianzhou-6.

　　Entering the application and development stage of the space station, the cargo spacecraft system team of the Fifth Academy of Aerospace Science and Technology Group expanded the fully sealed cargo spacecraft into two States: standard 8 tanks and improved 4 tanks, which were selected according to the upward demand of the space station to add propellant.

　　The improved fully sealed cargo spacecraft expands the spectrum of the fully sealed cargo spacecraft, improves the cargo loading capacity of the sealed cabin, and can reduce the radio frequency of the cargo spacecraft from four in two years to three in two years, thus effectively improving the comprehensive benefits of the space station project.

　　The Tianzhou-6 cargo ship is an improved fully sealed state with four containers. Based on the Tianzhou-5 cargo ship, the original unsealed rear cone section is changed into a sealed cabin, so as to expand the loading space of the sealed cabin and improve the cargo ascending capacity of the sealed cabin. At the same time, the first floor tank was cancelled, and the equipment in the original rear cone section cabin was adjusted to the propulsion cabin.

　　After the improvement, the effective loading volume of the whole ship’s materials has expanded by 20%, and the loading capacity of the whole ship’s materials has increased to 7.4 tons, which is the first time that the cargo loading capacity of China’s cargo spacecraft has exceeded 7 tons.

　　Aspect 3: "old partner" speeds up and starts again.

　　The Long March 7 carrier rocket and Tianzhou cargo spacecraft, which have joined hands for six times, are already a pair of "old partners". The Long March 7 carrier rocket has become a "freight train" in the "transportation corridor between heaven and earth", which provides material support for the normal operation of China’s space station with the launch frequency of one or two times a year.

　　While achieving continuous success, the development team of the Long March 7 launch vehicle is also continuously optimizing the rocket design and launch site measurement and development process.

　　"In terms of the measurement and development process, this task has optimized the ground measurement and control software, and carried out single machine, system and full arrow verification, and the reliability of the measurement and development process has been further improved. At the same time, after process optimization, the launch time of the launch site was shortened from 27 days to 25 days. " Shao Yetao, chief designer of the Long March 7 launch vehicle of the First Academy of Aerospace Science and Technology Group, said.

　　Looking back, since the first mission of the Long March 7 carrier rocket, the time required for the launch site workflow has been reduced from 38 days to 25 days. Perhaps in the eyes of ordinary people, 13 days is not surprising, but for these 13 days, the Long March 7 carrier rocket model team has gone for nearly 7 years.

　　Compressing time is by no means a simple cancellation of processes and steps, but a further optimization of processes on the basis of thorough understanding of technology. Guo Jingang, deputy chief designer of the Long March 7 launch vehicle of the First Academy of Aerospace Science and Technology Group, said that in the past, the team used high-precision leveling instrument to measure the verticality of the rocket, and then the team took the factory platform and other facilities as reference, which ensured the "standing" safety of the rocket, simplified the operation items of the launch site, and contributed to the overall cost reduction and efficiency improvement of the rocket.

　　Zhou Hong, deputy director of the power system of the Long March 7 launch vehicle of the First Academy of Aerospace Science and Technology Group, introduced that the development team has improved the reliability of rocket engines and other products to further eliminate weak links.

　　Aspect 4: More scientific experiments will be carried out in the future.

　　The Tianzhou-6 cargo spacecraft not only carries various materials, but also carries a number of loads for scientific experiments and verification.

　　Lv Congmin, deputy chief engineer of the space application system of manned spaceflight project and researcher of the Space Application Center of Chinese Academy of Sciences, said that after the rapid rendezvous and docking of the Tianzhou-6 cargo spacecraft and the space station, the astronauts will transfer the related products to the space station cabin, and carry out 29 scientific experiments and application experiments in four fields according to the mission planning, including space life science and biotechnology, microgravity fluid physics and combustion science, space material science and new technology experiments of space application.

　　"We will carry out four scientific experiments, including the research on the influence of space microgravity environment on stem cell lineage differentiation, the research on the 3D growth and tissue construction of stem cells, the molecular evolution research on the co-origin of protein and nucleic acid and the origin of codon, and the biomechanical research on the influence of microgravity environment on cell interaction and cell growth." Lu Congmin said.

　　According to the plan, the experimental device for biological exposure of space radiation outside the Mengtian experimental module will be used to carry out research on key technologies of space radiation damage assessment science and application, tolerance of microorganisms in extreme environment to space exposure environment and its mechanism, and photochemical behavior of life molecules under space exposure environment.

　　Lu Congmin introduced that in the field of space application new technology test, the space environmental effect test of components and components such as large-scale integrated circuits, new semiconductor devices, optical fibers and optoelectronic devices will also be carried out by using the general test device for components and components outside the space of the space experiment module, which will provide technical support for the research and development of new components and components and the application and protection of space.