What are the real skills of the "courier brothers" who go to the space station
The Chinese cargo ship Tianzhou 2 has docked with the Tianhe space station core module, paving the way for a crewed mission. Photo: CCTV
The Long March 7 launch vehicle is a new generation of medium-sized launch vehicle developed to meet the requirements of the China Space Station project to launch a cargo spacecraft. In April 2017, the Long March 7 Yao-2 rocket sent my country’s first cargo spacecraft, Tianzhou-1, into the scheduled orbit; after a lapse of 4 years, on May 29, 2021, the space "express service" was opened again, and the Long March 7 The Yaosan rocket sent the Tianzhou-2 cargo spacecraft into space.
It is reported that in addition to the 4 launch missions during the construction phase of the space station, the Long March 7 rocket will continue to be launched twice a year after entering the operation phase of the space station. So, what are the true abilities of the Long March 7 rocket to take on such an important task?
Skill one: great strength
After the manned space station is lifted off, the astronauts must be stationed at the space station, and the materials needed to eat, wear, use, and even breathe, as well as the fuel needed for the space station to maintain the correct orbit, must be delivered by the cargo spacecraft in time. To send cargo spacecraft carrying large quantities of materials into space on time, it is necessary to rely on "strong" and highly reliable launch vehicles.
According to the relevant designers of the General Department of China Academy of Launch Vehicle Technology (hereinafter referred to as "Rocket Academy", affiliated to China Aerospace Science and Technology Corporation), it benefits from green, high-energy liquid oxygen, kerosene fuel and a new generation of high-thrust liquid oxygen kerosene. With the engine, the Long March 7 rocket has a low-Earth orbit carrying capacity of 13.5 tons, which is more than half more than that of a carrier rocket using traditional fuel. Among them, the core stage and the six liquid oxygen kerosene engines on the booster can provide more than 700 tons of take-off thrust.
Skill 2: Smarter
In order to meet the needs of China's manned space station project to launch cargo spacecraft and future manned carrier rocket upgrades, developers have plugged in the "brain" of the Long March 7 "Express Brother" with intelligent wings and turned it into a fully digitally controlled rocket . With a fully digital control system based on the redundancy bus, the reliability of the rocket has been greatly improved.
It is understood that the design reliability of the Long March 7 rocket has reached 0.98, which is domestically leading and world-class. It can not only transit in the 8th strong wind, but also launch in the rain, regardless of wind and rain, it can transport the load accurately into orbit. It can be seen that by relying on the "smart" Long March 7 rocket to deliver goods on time, can the life of the astronauts in the space station be guaranteed and the smooth progress of the space station mission.
Skill three: very environmentally friendly
When an in-service rocket is launched, at the moment of ignition, the launch tower is always enveloped by a large amount of red smoke, and the tail of the rocket will also have red flames. When the Long March 7 rocket took off at the Wenchang Space Launch Site in China, the original red smoke disappeared and was replaced by a large amount of white smoke.
"The rocket propellants in service use dinitrogen tetroxide and unsymmetrical dimethylhydrazine. When launching, the incompletely combusted dinitrogen tetroxide is easily decomposed into red-brown nitrogen dioxide gas at room temperature. As the rocket takes off, this This kind of gas surrounds the launch tower, forming the red smoke we see. The Long March 7 rocket uses two new liquid oxygen kerosene engines with independent intellectual property rights. The particles and water vapor produced by insufficient combustion of kerosene are mixed and condensed into white Compared with the conventional propellant, the specific impulse (the impulse produced by the unit mass of propellant) is increased by 20%, and the thrust is increased by 60%." The related designers of the Rocket Academy’s General Department explained.
Skill four: can adapt
China's Wenchang Space Launch Site has a lot of moderate rain with a rainfall of 5 to 15 mm in 12 hours throughout the year. The rainfall is large and the climate is humid. Therefore, waterproofing has been listed as the top priority from the early stage of rocket development. "For example, waterproof treatment is required at the joints, small apertures and crevices of the rocket's sections; at the vent holes, the dual functions of exhaust and waterproof are realized simultaneously; for low-temperature liquid tanks that cannot be avoided after filling Condensate accumulation problems, opening drainage holes, etc..” The related designers of the Rocket Academy’s General Department enumerated.
In addition, the Long March 7 rocket also follows the 3.35-meter diameter design of the previous Long March rocket family. It can not only meet the launch requirements of the Wenchang Space Launch Site, but can also be transported by land to the inland launch site for launch. The launch adaptability is significantly stronger.
It can be seen that it is precisely because of the above advantages that the Long March 7 rocket can become the "successor" of my country's main rockets in service and the "main force" of future space launch missions. "In the future, it can not only meet the needs of my country's manned space station project to launch cargo spacecraft, but also undertake various types of launch tasks, shouldering the historical responsibility of technological advancement and upgrading of the Long March rocket." The relevant designers of the Rocket Academy's General Department emphasized .