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CZ-10 (Long March 10) 921 rocket

The Long March 10 carrier rocket [commonly known as "921 Rocket" from the code name " 921 Project " of China's manned spaceflight project] is a new type of manned carrier rocket developed according to the development plan of China's manned space program. The stage of aerospace is as big as the capability of the launch vehicle. In order to complete China's manned mission to the moon, it is necessary to master the super-large launch vehicle technology. my country is developing a new generation of manned launch vehicle. It is a super-large launch vehicle that takes both manned and cargo tasks into account. It was officially unveiled for the first time at the Zhuhai Air Show, and was later officially named the Long March 10 rocket.

According to the plan announced by China's aerospace department, in the future, China will launch two Long March 10s, and then dock them in space to form a manned lunar probe for the implementation of the manned lunar landing program. But this is only the first step. China's manned moon landing plan is not for "fake fame", but for the establishment of a lunar base, the development and utilization of lunar resources and the construction of a deep space exploration lunar transfer station. Then, in the future, China planned to go to and from the moon very frequently, and the manned launch vehicle of the Long March 10 level is very suitable as a manned moon landing tool, and it is likely to become the main rocket for China to build a lunar base.

The recently revealed primary plan for China’s crewed moon landing before 2030 where China in which attempt to use two launch vehicles and carry out two rendezvous and docking missions in lunar orbit, has drawn attention worldwide, and the China Space News, an authority news service for state-owned aerospace contractors, further explained that such plan would be highly effective in using China’s most advanced space technology and more reliable and economic given it does not rely on the development of a special super heavy-lift rocket to achieve the goal of sending taikonauts to moon.

When the US and Soviet Union tried to execute a manned moon landing, the rendezvous and docking technology had yet to mature and it was also difficult to launch two or more launchers one after another within a short time period. So to develop a super heavy-lift rocket to send moon lander and crewed spacecraft all in one go was the easier and safer path to achieve the goal.

But things are different now. The current reality is that to develop a new-generation heavy-lift carrier rocket would take longer time and cost much more, let alone the difficulty. For example, the development for the US Space Launch System (SLS) took more than 10 years and counting, cost reached somewhere around $50 billion and the SLS is still using interim upper stage, the report pointed out. Since China has mastered rather matured reliable space rendezvous and docking technology, a two-launcher path would be more reasonable and also feasible.

China will attempt to use two launch vehicles to send a moon surface lander and manned spacecraft into lunar orbit before they carry out rendezvous and docking with each other. Following this maneuver, the taikonauts onboard the manned spacecraft will enter the lander. Taikonauts will carry out scientific exploration and sample collecting after they descend to the moon’s surface using the lander. After completing all preset missions, they will engage the lander to ascend and dock with the manned spacecraft waiting in the lunar orbit. Then taikonauts will take the lunar samples and ascend from moon surface with the lander that will dock with the manned spacecraft again in lunar orbit before they return to Earth in the manned spacecraft.

The Long March 10 rocket has been officially approved. Its overall plan is to connect 7 YF-100K engines with a 5-meter core in parallel. The first stage has 3 core stages connected in parallel with 21 engines, and the second stage has two high-altitude YF-100K engines. For the engine scheme, in order to support the manned mission to the moon, the third stage will use three YF-75D liquid oxygen and liquid hydrogen engines to provide sufficient speed increments.

The Long March 10 rocket has a low-earth orbit (LEO) carrying capacity of up to 70 tons and a lunar orbit (LTO) carrying capacity of 27 tons, which is equivalent to the US SLS Block1 rocket. It is the cornerstone of China's manned moon landing. The scale of my country's manned mission to the moon is also roughly the same as that of the American Apollo manned mission to the moon. According to the current plan, a manned mission to the moon will launch two Long March 10 rockets, which will transport the manned spacecraft and the lunar surface respectively. The lander is sent into the lunar orbit, and after docking in the orbit around the moon, it lands on the moon.

Two configurations are designed. The first one is with booster, which is mainly responsible for sending the lunar lander and the lunar landing spacecraft into the earth-moon transfer orbit. Due to the long delivery distance, the rocket thrust of this configuration is also greater. The height is about 92 meters, the take-off mass is about 2187 tons, and the take-off thrust is about 2678 tons, and the carrying capacity of the earth-moon transfer orbit is not less than 27 tons.

The booster-free rocket derived from this type of rocket can carry out space station astronauts and cargo transportation tasks, and the first sub-stage has the function of reusability. The total length is about 67 meters, the take-off mass is about 748 tons, the take-off thrust is about 873 tons, and the low-earth orbit carrying capacity is not less than 14 tons. It was expected that the rocket will meet the conditions for its first flight in 2027, and will become an important strategic support for the construction of China's space power.

The Long March 10 rocket inherits the 5-meter-diameter rocket body of the Long March 5 rocket, and the pump-back swing YF-100K engine developed from the YF-75D engine and the YF-100 engine, through a core stage similar to the "Falcon Heavy" rocket The parallel mode realizes the carrying capacity of LEO 70-ton class / LTO 27-ton class. The overall plan is reasonable and the technology maturity is high. Various research and development work is advancing in an orderly and rapid manner. The rocket is planned to make its first flight around 2027.

China's aerospace department has long-term considerations for setting the sea-level thrust index of YF135 as 3600kN, and it is likely to be used as the core stage and booster engine of the second phase of the improved Long March 10. In fact, compared with YF100, YF135 is not only as simple as doubling the thrust, but also has advantages in terms of specific impulse and thrust-to-weight ratio. It is understood that the sea level specific impulse of YF100K is 301.84S, and the thrust-to-weight ratio is 70. YF135 is 20.16S higher than YF100 in terms of the most critical specific impulse, and the thrust-to-weight ratio has also increased by 28.57%.

Taking the Long March 10 carrier rocket as a reference object, replacing 21 YF100Ks with 9 YF135s can increase the weight of the second stage by about 8.9647% without reducing the separation speed of the second stage and the core stage. This is achieved without considering the number of pipeline flow paths and the weight reduction of the control mechanism. If these are taken into consideration, the weight reduction effect will be even more significant.

The greatly reduced number of engines can also greatly improve the reliability of the rocket. The Soviet N1 rocket once had too many engines, resulting in extremely poor reliability of the rocket, which eventually led to the tragic ending of repeated trials and failures. As a new generation of manned rockets in China, reliability is the most important technical indicator of Long March 10. In the future, replacing YF100 with YF135 will greatly improve the reliability and capacity of Long March 10.

Since YF100K has the ability to be reused, if YF135 is to replace YF100K at a ratio of 3:7 in the future and become the core stage and booster engine of the Long March 10, it must also have the ability to be reused, otherwise it will lose its core Cost advantage. Therefore, there was reason to believe that YF135 may eventually develop a reusable model like YF100, so that the Long March 10 will become a new generation of manned launch vehicle with low cost and high reliability.

The First Institute of the Science and Technology Group focuses on general research and development. Among them, the first sub-stage of the non-boosting configuration rocket has the ability to be used repeatedly, and will adopt advanced technology and innovative design, so comprehensive tests are required to verify the feasibility and correctness of the scheme. The Beijing Intensity Environment Research Institute of the First Academy of China Aerospace Science and Technology Corporation vompleted a series of key technologies in July 2023 for the reusable first sub-stage of the unassisted propulsion configuration rocket derived from the Long March 10 carrier rocket. The successful completion of the principle test marked a key step in the technical verification of the first sub-stage of this type of rocket.

The CZ-10 will be reused in the first stage before 2032. The core stage will use the network system of cables, not the chopsticks recovery method used by SpaceX. This saves the weight of three legs, which should be several tons. When talking about rocket recovery, the first thing people think of is the Falcon 9 rocket developed by SpaceX. As the "hands-on" in the rocket recovery industry, it attempted the difficult offshore vertical recovery mission on April 9, 2016. The first-stage rocket landed steadily on the offshore platform. The recycling of the Falcon 9 rocket has also profoundly affected China's aerospace companies, and everyone has aimed at rocket recycling technology , trying to achieve "cost reduction and efficiency increase" of rockets.

The engine is the most valuable part of the rocket. It is understood that in the cost of rocket development, the cost of the engine often accounts for more than half. Through rocket recovery, the engine can be reused, and the cost may be reduced. At the same time, the delivery capability of the rocket may be further improved -in the past, it was necessary to rebuild a rocket, but now it needs to overhaul the recovered rocket.

The first sub-stage of the domestically produced new-generation manned space launch vehicle Long March 10 is designed according to the requirements of reusability. The currently announced plan plans to use a delicate tethered hanging recovery method. It has been seen that the First Academy of Aerospace Science and Technology has been conducting a sub-level grid rudder test recently. In this way, the grid rudder hung by the cable is undoubtedly subjected to huge force, and the requirements for the structure must be extremely high.

China successfully carried out a trial test 23 July 2023 on the main engine of the Long March-10, a new carrier rocket designed for manned moon landing missions, on Saturday, as the country actively makes progress on the road to realizing its goal of landing taikonauts on the moon by the year 2030. The test assessed all the requirements for the engine, and provided strong support for the solidification for its technical state, the establishment of the technical baseline of the product and improving reliability, the Global Times learned from the China Aerospace Science and Technology Corporation (CASC) 6th Academy on Sunday.

The engine used in the test employed advanced liquid oxygen as fuel and can reach a thrust of 130 tons. It is an updated version of China's strongest active rocket engine, which has a thrust of 120 tons and is used in rockets including the Long March-5. Although the thrust of the engine has only improved by 10 tons, the first stage of the Long March-10 will reportedly carry 21 engines. This will add another 210 tons of the thrust in total.

By 2023 China was about to start a major construction project at the Wenchang launch site in Hainan to build a new assembly building and launch station for the Long March 10 rocket, as well as a supporting transfer launch platform. The Long March 5 rocket has a total length of about 57 meters and a launch weight of about 880 tons. The scale is more than twice that of the Long March 5. The existing ground launch facilities for launching the Long March 5 cannot be directly used to launch the Long March 10 rocket. It is necessary to build new supporting facilities such as a more powerful launch station. The new three-vertical test and launch mode will be used to simplify the support facilities of the launch site and launch area, and to have rapid launch capabilities to meet the needs of rapid launch of two Long March 10 rockets in future manned missions to the moon.

Why would Academician Long call it the Long March 5 DY? The outside world speculates that there may be two reasons. First of all, the new 921 rocket uses 7 YF-100K engines for the first stage, 2 YF-100M engines for the second stage, and 3 YF-75E engines for the third stage. These engines, especially the YF-75 series, have more or less been tested on the Long March 5, and have a technical inheritance relationship with the Long March 5. China's earliest manned moon landing rocket was designed on the basis of the Long March 5, with a longer rocket body and 6 boosters bundled. It was only later replaced by the current new 921 rocket, so the name still inherited the previous Long March 5 DY. Another point is Academician Long's personal preference. He refers to many rockets as the Long March 5 series.

Of course, both the Long March 5 DY and the Long March 5 ZRL are just their temporary names. This suffix naming method is not the official naming habit of Chinese rockets. It is estimated that they will have their own "big names" after they are officially launched in the future. Regardless of what China's manned moon landing rocket and the new generation of low-Earth orbit manned rockets are called, they will all become the "pillar" of my country's manned spaceflight.

For a long time there was no Long March 10. Numbers in China range between auspicious and ominous mainly depending on their pronunciation and on their meaning in feng shui (a Chinese philosophical system for harmonizing people with their environment). The number 10 is rarely used in Chinese culture to symbolize anything because 10 is considered a "full" number. Chinese culture value moderation, meaning too much can be just as bad as not enough. Chinese also believe cycle of life, whatever goes up will go down. anyone who reaches the peak, will only decline. Number 10 is a peak number, so reaching 10 is not a good thing, it is the best one can get and the beginning of downfall.

Chinese like number 8 and number 6 because in some dialect, pronunciation of 8 is similar to "good fortune", number 6 is similar to "everything goes according to my will"; while number 9 is a number for highest nobility, often only emperor can use number 9 (have 9 dragon stitched on his clothing and such). October 10th [10-10, double 10] is not considered lucky, but it is celebrated as the national day of Republic of China. It marks the day of Wuchang uprising happened on October 10th, 1911. The uprising leads to Xin Hai Revolution, which eventually ended the Qing Dynasty, started Republic of China.The numeral 4 is considered as “death” due to the pronunciation in Chinese, but the LM-4 family of rockets is a successful Chinese launch vehicle.