At 1:56 a.m. on May 10, the Long March 7 Yaowu carrier rocket carrying the Tianzhou-4 cargo spacecraft was ignited and lifted off at the Wenchang Cosmodrome, and about 10 minutes later, the spacecraft and the rocket successfully separated and entered the predetermined orbit, and the launch was a complete success.
The continental space station has entered the construction stage this year, and this launch is the first flight mission in the construction stage of the space station, which bears the heavy responsibility of "taking the lead" and has made a good start for the six launch missions of this year's manned space project.
The Surging News (www.thepaper.cn) learned from the China Academy of Launch Vehicle Technology, a subsidiary of China Aerospace Science and Technology Group Co., Ltd., the general development unit of the Long March 7 rocket, that in order to meet the needs of future space station operations, the institute optimized the process before the launch of the Long March 7 Yaowu carrier rocket, reducing the measurement and firing cycle by 4 days, from the original 31 days to 27 days. This is also the first time that the Long Seven rocket has been tested and launched in one month.
Image source: China Academy of Launch Vehicle Technology, a subsidiary of China Aerospace Science and Technology Corporation
Successive battles and victories, reliability has reached the international advanced level
Long March 7 carrier rocket (hereinafter referred to as "Changqi rocket") is a new generation of medium-sized carrier rockets in the mainland, with a take-off weight of 597 tons and a carrying capacity of 13.5 tons in low-Earth orbit, since its first flight, it has carried out four launch missions of the Tianzhou series of cargo spacecraft, delivering cargo and propellant and other materials to the space station and space laboratory, so it is known as "space express brother".
According to Shao Yetao, the overall chief designer of the rocket dean seven rockets, this is the fourth time that the Changqi rocket and the Tianzhou series cargo spacecraft have joined hands to go to space, the "courier brother" and its "passengers" have been very "tacit understanding", the overall technical state of the rocket has gradually stabilized, and the flight reliability assessment value has reached 0.9838, reaching the international advanced level.
According to the mission plan, in the 2022 space station construction stage will implement 6 missions to complete the construction of the mainland space station in orbit, including two "Tianzhou" cargo spacecraft launch missions, after the successful launch of Tianzhou 4, the Shenzhou 14 manned spacecraft will be launched next month, and 3 astronauts will be stationed in the core module and stay in orbit for 6 months; then it is planned to launch the space station Wentian Experimental Module and the Dream Experiment Module in July and October respectively, forming a three-cabin "T" basic configuration with the core module to complete the orbit construction of the Chinese space station Subsequently, the Tianzhou-5 cargo spacecraft and the Shenzhou-15 manned spacecraft will be launched, and the Shenzhou-15 flight crew consists of 3 astronauts, who will stay in orbit for 6 months after rotating with the Shenzhou 14 astronauts.
Continuous optimization, the launch cycle was reduced to less than one month for the first time
"Aerospace is a big system engineering, even if it is a process detail change, it needs to be analyzed and analyzed by the whole system to achieve perfection." Because of a slight carelessness, the omission is likely to have an unexpected effect. Reducing the rocket test and firing cycle by 4 days - this is a major process improvement task of the Long March 7 Yaowu rocket, which not only challenges the comprehensive performance of the Long Seven rocket, but also tests the adaptability of the launch team members in the high-intensity working environment, and the various subsystems of the rocket must carry out process optimization work at the same time to achieve the final goal. Meng Gang, commander-in-chief of the Changqi rocket, pointed out.
According to Fan Hong, deputy chief designer of the Changqi rocket, the restoration of ground equipment is the first task for the rocket to enter the field, and it is also a prerequisite for normal rocket testing. The moment the Long March 7 Yaowu notice entered the field, the ground response team of the control system gathered together to discuss the personnel and work arrangements of the mission, the team was also responsible for 3 models and 5 states of ground equipment, the launch task and the design work intersected in parallel, the equipment of the launch site was facing overdue, and the requirements of the compression process and streamlining personnel were to be met.
"For multi-type general ground equipment, the compression process and streamlining of the project with quality and quantity are a matter of overall planning, and it is necessary to get rid of the original task, and link up with the previous and post-engines, so that the process is 'alive', the more the preliminary work is done, the faster the test task will be carried out after entering the field, the better." Fan Hong said. The team optimized and merged the work of the ground equipment recovery stage, saving about 2.5 days of test time; in the face of the problem of overdue ground equipment, it was deployed in advance, sorted out spare parts, and carried out stand-alone self-test. It is precisely these effective measures that allow the ground equipment of the Long March 7 Yaowu rocket control system to resume one link at a fast pace.
In order to further compress the time, the Long Seven rocket team also compressed the rocket product out-of-the-box workflow from 3 days to 2 days.
According to Cui Yun, the technical leader of the Changqi rocket assembly, on the afternoon of April 10, the Long March 7 Yaowu rocket opened the product out of the box. In order to achieve the goal of optimizing the process, the booster self-test, the rocket core stage out of the box and the fairing out of the box were carried out in parallel in different work plants for the first time. "The team dispatchers have fully communicated with all parties in advance, formed a consensus before leaving the box, avoided the increase in time due to coordination and communication in the process of leaving the box, and reasonably arranged the front-line operators, and the second-line personnel supported the front-line operators under the premise of pre-post operation knowledge training in advance, and did a good job in the auxiliary work of the front-line operators." Cui Yun said.
After completing the unpacking of all the boosters of the Long March 7 carrier rocket, in order to ensure that the rocket core stage and fairing are out of the box at the same time in the two plants, the assembly team is fully engaged, and the craftsmen, dispatchers, inspectors and personnel responsible for quality and informatization all arrive at the scene, and all of them are riveted for the same goal. By the afternoon of April 12, the assembly team was precisely planned, precisely arranged, and fully dispatched, compressing the 3-day work to 2 days, and fully completed the product out of the box.
In order to accurately realize the redundancy time of the self-inspection process of the long march 7 carrier rocket structure, before departure, the development team made multiple rounds of changes to the work rules of the launch site, integrated the design, process, front-line workers and operators' opinions, system collation, multi-party coordination, and sorted out the execution time of each operation link, and accurately changed the process time error to less than 10 minutes. After 5 consecutive days of high-intensity work, the Haruka 5 rocket completed the vertical assembly one day earlier than before, and the process was compressed by one day as scheduled.
In terms of compressing the launch time, the team also turned its attention to the launch day, and after efforts, the launch day process was compressed by 4 hours.
"The long seven rockets of this launch mission will carry out liquid oxygen-kerosene parallel refueling, reducing the 12-hour process on the launch day to 8 hours, which is an extremely challenging task, and the development team will examine each system, confirm countless scenarios, and envisage multi-party collaboration, and then complete the organic integration of the rocket multi-system launch process." Shao Yetao, chief designer of the Changqi rocket, said.
As early as more than 3 months before the launch team entered the launch site, the seven development teams of the rocket dean began to organize various professional groups to analyze the changes in the parallel filling process of liquid oxygen kerosene, determine the principle of parallel process changes, from the process change plan to the process change implementation plan, and the launch day plan preparation for a full range of preparations and planning.