Long March 2F (code: CZ-2F, short for: Long March 2F, nickname: Shenjian) is affiliated to China Aerospace Science and Technology CorporationChina Academy of Launch Vehicle TechnologyA large two-stage bundled booster carrier rocket developed by the General Manager is mainly used by China to launch ShenzhouManned spacecraftAnd large target aircraft to low Earth orbit[46]。
Long March 2F is a carrier rocket developed on the basis of Long March 2E bundled rocket, in accordance with the requirements of launching manned spacecraft, with the goal of improving reliability and ensuring safety[1]。The rocket consists of four liquid boosters, a core primary rocket, a core secondary rocketFairingandEscape towerform.The rocket adopts the "three vertical" test launch mode of vertical assembly, vertical test and vertical transportation for the first time.The Long March 2F rocket has been developed since 1992. On November 19, 1999, it was launched for the first time and successfully sent China's first experimental spacecraft "Shenzhou I" into space.Long March 2F has successfully launched Shenzhou series spacecraft for many times, and has become the "star" rocket of China's Long March series carrier rocket family[2]。
At 20:59 on April 25, 2024, Beijing time, the Long March 2F Remote 18 carrier rocket carrying the Shenzhou 18 manned spacecraft ignited and launched at Jiuquan Satellite Launch Center. About 10 minutes later, the Shenzhou 18 manned spacecraft successfully separated from the rocket and entered the scheduled orbit[65]。
From the 1960s to the 1970s, the world's space powers the United States and the Soviet Union successively implemented manned space exploration.On April 12, 1961, Soviet cosmonaut Gagarin made his first space flight.On July 21, 1969, American Armstrong landed on the moon for the first time.On April 19, 1971, the Soviet Union took the lead in launching a manned space station[3]。
In the 1980s, China launched the "high-tech development research planning demonstration".
In March 1986, the State Council of China organized the formulation of China's high-tech development research plan, known as“863 Program”[4]。
In 1987, China began to implement the "863 Plan", which is divided into seven key areas. One of them, "863-2", is to develop a blueprint for China's manned space industry.It took five years from 1987 to January 1992 to carry out the technical and economic feasibility demonstration of manned spaceflight, and then entered the stage of preparation for project approval.
On September 21, 1992, after years of careful argumentation, the Standing Committee of the Political Bureau of the CPC Central Committee decided to implement the code“Project 921”The manned spaceflight project of[5-6]。
As an important part of the manned space project, Long March 2F rocket has become one of the seven major systems of China's manned space project.When the project is approved for development, not only the performance indicators such as carrying capacity and orbit entry accuracy, but also the reliability and safety indicators are taken as the most important design parameters. It is determined to carry out the development according to the goal of reliability not less than 0.97 and safety not less than 0.997[7-8]。
Long March II Series Rocket
Development history
At the end of 1992, the development of Long March 2F rocket was officially launched[9-10]。
On November 20, 1999, the Long March 2F rocket was launched for the first time and successfully, bringing China's first unmanned experimental spacecraft“Shenzhou 1 ”Go into space.
On October 15, 2003, the Long March 2F rocket made China's first astronautYang LiweiAfter the Soviet Union and the United States, China became the third country to send humans into space.
In 2023,The Long March II F-17 rocket has completed various tests and is scheduled to leave the factory in April.At the same time, the Long March II F Yao18 rocket passed the review and will begin final assembly soon.[54]
In May 2023, the Long March II F series carrier rocket will continue to undertake the Shenzhou 16 manned flight mission.The Long 2F carrier rocket is the only one in service in China with a fault detection system and escape system.As it undertakes the manned launch mission, its biggest characteristics are high reliability and safety. Its reliability index reaches 0.98, and its safety index reaches 0.997. The long 2F remote 16 rocket to be launched this time has improved its technical status compared with the remote 15 rocket.[56]
In November 2023, according to the China Aerospace Science and Technology Corporation, the Long March 2 F Remote 19 carrier rocket entered the final assembly state.The "Divine Arrow" will launch the Shenzhou manned spacecraft in 2024.[59]
Technical characteristics
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overall design
Long March 2F carrier rocketLong March II EBased on the rocketManned spacecraftTo improve reliability and ensure safety.The rocket was composed of four liquid boosters, a core primary rocket, a core secondary rocket, a fairing and an escape tower. It was the rocket with the largest takeoff mass and the longest length of all carrier rockets in China at that time.The launch vehicle has ten subsystems, including rocket body structure, control system, power unit, fault detection and processing system, escape system, telemetry system, external measurement safety system, propellant utilization system, additional system and ground equipment. In order to take into account the launch of satellites, the interface and installation position of the effective load attitude adjustment and orientation system are reserved.The fault detection and processing system and escape system are added to ensure the safety of astronauts. Their role is to monitor the status of the carrier rocket before the spacecraft enters the orbit. In case of major faults, the spacecraft carrying astronauts can safely leave the danger zone[12]。
Arrow body structure
Overall Structure Diagram of Long March 2F
Long March 2F carrier rocket is composed of 10 systems, including rocket body structure system, power plant system, control system, propellant utilization system, fault detection and processing system, escape system, telemetry system, external measurement safety system, additional system and ground equipment system.
booster, core level I, core level IIFairing、Escape towerThe body structure of the rocket consists of the "body" of the rocket.Boost engine, primary engine and secondary engine are the "power and heart" of rockets.The control system is the "brain and nerve" of the rocket.In order to make full use of the fuel loaded on the rocket, a propellant utilization system is also designed on the rocket, which can ensure that the oxidizer and combustion agent of the secondary rocket are burned at the same time[13-14]。
dynamic system
The Long March 2F rocket inherits the main configuration of the Long March 2E rocket, that is, the core stage is bundled with four boosters.The booster is lengthened on the basis of Long March 2E, and the position of the binding connection point is moved from the short shell in front of the first stage rear box to the section between the first stage boxes;The fairing is newly designed according to the requirements of the spaceship and escape, and an escape tower is added on the fairing;The tail wing is added at the rear of the booster.With a total length of 58.3 meters and a take-off weight of 479.8 tons, the rocket is the highest and heaviest rocket developed by China in the early 21st century.
The core stage diameter of the Long March 2F rocket is 3.35 meters, the booster diameter is 2.25 meters, the fairing diameter is 3.8 meters, and the maximum cross section diameter of the rocket is 10.2 meters.Both the rocket core stage and booster use nitrogen tetroxide and unsymmetrical dimethylhydrazine propellants. The first stage charge propellant is about 186.6 tons, the second stage charge propellant is about 84.8 tons, the booster charge propellant is about 41.5 tons, and the rocket charge mass is 481.9 tons.When the perigee altitude is 200 km, the apogee altitude is 350 km, and the orbital inclination is 42.4 °, the carrying capacity is greater than 7.8 tons[14-15]。
In order to ensure the safety of astronauts and ensure that astronauts can still escape from dangerous failed rockets even in case of sudden accidents, the Long March 2F carrier rocket has set up a fault detection and processing system for parameter detection and judgment. When major faults are found in the rocket, escape commands are issued and executed according to the escape mode.The escape system of the rocket is the actuator of the fault detection and processing system. The tip at the front end of the rocket is the escape tower.
In order to measure the trajectory of the rocket and receive the ground escape command and safety control command, the rocket has set up its own safety system.In order to understand the working conditions of the rocket during flight, the rocket is also equipped with a telemetry system, which can measure, record and send all the working parameters and environmental parameters of the rocket during flight, provide detection parameters for the fault detection and processing system, and provide real-time telemetry parameters for ground fault judgment. Both systems need to work together with ground measurement equipment,The ground TT&C station and the "Yuanwang" survey ship in the Pacific Ocean need to receive the signals sent back by the rocket and send corresponding control commands to the rocket.
In addition, the rocket also needs an additional system mainly composed of depletion shutdown signal system, filling level measurement, propellant temperature measurement, perpendicularity adjustment and overall ground comprehensive test network, as well as a ground support system composed of ground launch platform, propellant filling equipment, transfer vehicle, hoisting equipment, ground test equipment of various systems, to jointly complete the rocket assembly at the launch siteA series of preparations for rocket launch, such as test and transition[16]。
Escape system
An automatic fault detection and processing system has been added to the Long March 2F rocket. This system can automatically detect faults during the launch phase and the ascent phase of the spacecraft. Once there is a problem, it will automatically alarm.If the astronauts are on the tower and haven't entered the cabin yet, they can jump into the escape cloth bag on the tower nearby. The cloth bag is made of a special canvas with strong elasticity. After jumping in, the astronauts use the resistance of their limbs to control the descent speed, and slide from the top to the safe area of the basement like taking a soft slide.If the astronauts have entered the cabin, this system can command the escape tower at the top of the rocket to automatically ignite, pull the spacecraft back cabin away from the rocket, and land safely[10]。
In order to ensure the safety of astronauts, the Long March 2F rocket also cancels the function of other rockets that will automatically self destruct if their attitude is unstable, and is equipped with an escape system that can be started at any time in case of an accident.Escape system is also calledEscape towerAt the top of the spaceship, the tower is 8 meters high and looks like a lightning rod on a rocket from a distance.Its mission is to pull the orbital capsule and return capsule to separate from the rocket in case of failure of the rocket between 900 seconds before the rocket takes off and 160 seconds after it takes off, that is, when the flight altitude is 0-110 kilometers, and land in a safe area to help the astronauts on the spacecraft escape from the danger[17]。
Hoisting of escape tower F of Long March 2
Telemetry system
In view of the fact that in the past flight, the ground control center relied on the corresponding telemetry parameters to know the rocket shutdown, separation and other actions, but the relevant parameters are indirect and not intuitive.The sixth Long March 2F carrier rocketTelemetry systemThe image measurement system is set for the first time in for monitoringboosterSeparation, interstage separationFairing separationThe separation process of ship and arrow enables the ground control center personnel to directly "watch" the separation process.
Compared with telemetry parameters, image information needs to occupy a wider data band, which was originally allocated toTelemetry systemOfData transmission speedIt is not enough. It is necessary to adjust the telemetry parameters in general and adjust the required frequency band for the image information data.At the same time, an image compression processor is added to compress the data amount of image information as much as possible.Secondly, a series of equipment such as CCD camera device, image compression processor, image integrated controller, etc., which need to fly in the sky, will also experience the test of harsh rocket flight environment, including high overload, vibration, high temperature, vacuum, etc.Therefore, the design standards and tests of relevant equipment need to pass the assessment of high standards[18-19]。
Design parameters
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Basic parameters
Basic parameters of various types of Long March II F
Long March II F basic type*
（CZ-2F）
Long March II F improved
Launch Manned Spacecraft
（CZ-2F/G）
Long March II F improved
Launch Tiangong type
（CZ-2F/G）
Rocket length/m
fifty-eight point three four
fifty-two
Fairing diameter/m
three point eight
four point two
Core diameter/m
three point three five
Booster diameter/m
two point two five
series
two point five
reliability
zero point nine seven
Security
zero point nine nine seven
Whether there is escape tower
yes
yes
nothing
Oxidant+propellant
Nitrogen tetroxide+UDMH
Takeoff thrust/kN (t)
5923 kN (604.387 t)
Takeoff mass/ton
four hundred and seventy-nine point eight
four hundred and ninety-seven
four hundred and ninety-three
Takeoff thrust weight ratio
one point two six
one point two two
one point two three
Carrying capacity/ton
eight point four
eight point eight
Payload mass/ton
seven point eight
eight point one three
eight point six[20]
Index interpretation
reliability index : Reliability 0.97, indicating that three failures may be allowed after 100 launches.Reliability index is the probability of a product completing a specified task within a specified time and under specified conditions.
Safety index: Safety 0.997, which means that the rescue measures taken for 1000 failures during launch are only allowed to fail three times.The safety index represents the conditional probability that the astronauts can return safely when the rocket fails.The most prominent feature in the design of Long March 2F carrier rocket is the addition of fault detection and processing system and escape system.Their calculation is based on a large number of parameters and consists of two parts: a large number of ground test data+flight data of the actual launch of this type of rocket[43]
Long March 2 F General Assembly
Flight procedures
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Typical flight procedures of Long March 2F
Time (seconds)
event
remarks
T-40.0
Influence
Swing rod open
T-30.0
Swing the pendulum in place
-
T-3.0
ignition
-
T+0.0
take off
-
T+12.0
Program turn
-
T+120.0
Escape tower separation
This item is not available for launch Tiangong type
T+154.80
booster separation
-
T+159.0
First level shutdown
Level 1 completes the mission, and Level 2 continues to complete the launch mission
T+159.50
1、 Secondary separation
-
T+212.50
Throwing fairing
-
T+463.10
Secondary host shutdown
-
T+582.10
Level II travel machine shutdown
-
T+585.10
Arrow ship separation
Arrow separation[9]
Derivative model
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The Long March 2F carrier rocket has the basic type of Long March 2F and the improved type G and T1 of Long March 2F:
Long March II F basic type
The basic type of Long March 2F, referred to as the Long March 2F rocket (CZ-2F), or prototype, is used for the manned mission of launching Shenzhou spacecraft and installing escape towers.
The rocket has a total length of 58.34 meters, the first and second stages have a diameter of 3.35 meters, the booster has a diameter of 2.25 meters, the fairing has a diameter of 3.8 meters, and the takeoff mass is 479.8 tonsPayloadSent to the earth with 200 km perigee, 350 km apogee and 42 ° inclinationLow Earth orbit。Long March 2F basic model has successfully launched "Shenzhou I" to "Shenzhou VII" spaceships, making historic contributions to China's successful manned space flight.On September 25, 2008, the last basic launch was used, and production was stopped[1]。
Long March II F/G
The Long March 2F improved manned spacecraft carrier rocket, referred to as the Long March 2F to Y rocket (CZ-2F/G), is used to replace the basic Shenzhou spacecraft manned mission (installationEscape tower）The change of LM2F is based on the basic model of LM2F. The ellipsoidal roof on the top of the booster propellant storage tank is changed to a conical roof to increase the propellant storage capacity, and the master-slave redundancy of dual laser inertial units is used to increase the thrust of low Earth orbit.Compared with the base type, there are more than 170 improvements and more than 190 changes in technical status in the Chang 2F modification.The takeoff mass of the rocket is about 493 tons. The fairing diameters of the launch manned spacecraft model and the launch target aircraft or space laboratory model (without escape tower) are 3.8 meters and 4.2 meters respectively, and the total length of the rocket is 58.34 meters and 52 meters respectively.The 8.8 ton payload can be sent into the Earth's low Earth orbit with a perigee of 200 km, an apogee of 350 km and an inclination of 42 °.fromShenzhou VIIISince the launch mission, the basic type of Long March 2F will no longer perform the mission, and the follow-up mission will be changed from Long March 2F[21][50]。From the aspect of appearance, the "Y" series of Long March 2F rocket, as a manned rocket, is different from the "T" series for carrying goods in that it has a pointed“Escape tower”。[60]。
Long March II F/T1
Long March 2F improved target aircraft carrier rocket, referred to as Long March 2F to T rocket (code: CZ-2F/T1), is used for unmanned missions and space stations such as Tiangong 1 (without escape tower, the top of fairing is changed toVon Karman curve）。The rocket fairing first used "von Karman curve".When launching the "Tiangong-1" target aircraft, the biggest change in the shape of the rocket was that the length of the fairing increased from 10.7 meters to 12.7 meters, and the maximum diameter also increased from 3.8 meters to 4.2 meters."Von Karman curve" can reduce air resistance and pulsating pressure;The second is to reduce the load impact of the rocket body structure, which is also beneficial to the load design of the fairing[22]。The top of the "T" series fuel tank of the Long March 2F rocket was improved.In this way, more fuel can be carried and the thrust can be increased, so that the carrying capacity of the Long March II F "T" series rocket can be increased from 8.1 tons to 8.6 tons, which is more powerful and can lift a heavier spacecraft than Shenzhou spacecraft[60]。
Comparison of the top of Long March II F "T" series and "Y" series rockets[60]
LEO：Low Earth orbit(Low Earth orbit), also known as low earth orbit, refers to the orbit where the spacecraft is relatively low from the ground.
Launch mission
On October 12, 2005, the Long March 2F rocket will become an astronautFei Junlong、Nie HaishengThe launch into space and the realization of multi person and multi day flight tests also marked the successful realization of the "first step" of China's manned space program.
On September 25, 2008, the Long March 2F rocket willZhai Zhigang、Liu BomingandJing HaipengWhen three astronauts were sent into space, Zhai Zhigang took the first step for Chinese people to walk in space, making China the third country in the world to independently master the key technology of space extravehicular activities.
On November 3, 2011, the Long March 2F rocket willShenzhou VIIIThe spaceship was successfully launched. Shenzhou VIII spaceship andTiangong No.1The target aircraft successfully achieved rigid connection and formed a combination. China's first space rendezvous and docking test was successful, becoming the third country in the world to independently master space rendezvous and docking technology.
On June 16, 2012, the Long March 2F rocket at Jiuquan Satellite Launch CenterShenzhou 9The spacecraft was successfully launched, and the Shenzhou 9 spacecraft and Tiangong 1 manned rendezvous and docking mission was a complete success, achieving another major breakthrough in China's space rendezvous and docking technology, marking the decisive and important progress of the "second step" strategic goal of China's manned space program.
On October 17, 2016, Long March 2F rocket was successfully launchedShenzhou 11The spacecraft, astronauts Jing Haipeng and Chen Dong, successfully stayed in space for 33 days and completed a series of scientific and technical tests.Completed the "second step" of China's manned space program[11]。
On June 16, 2021, it was learned from the press conference of the Shenzhou 12 manned flight mission that the General Headquarters had studied and decided to launch the Shenzhou 12 manned spacecraft at 9:22 on June 17, Beijing time, and the Long March 2F remote 12 rocket carrying out the launch mission would be filled with propellant[38]。
At 9:22 on June 17, 2021Shenzhou 12The Long March 2F remote 12 carrier rocket of manned spacecraft was launched at Jiuquan Satellite Launch Center and put Shenzhou 12 into the scheduled orbit[40]。Then the chief designer of Long March II FeasilyInterview with CCTV[44]。The Long 2F rocket participated in the whole processChina Manned Space ProjectAt each step of the "three-step" strategy, more than ten missions were carried out, including the launch of five unmanned spacecraft, two space laboratories and seven manned spacecraft, all of which were successful, and 12 or 17 astronauts were sent into space[47]。
At 0:23 on October 16, 2021, the Long March 2F remote 13 carrier rocket carrying the Shenzhou 13 manned spacecraft ignited and launched at Jiuquan Satellite Launch Center. The Shenzhou 13 manned spacecraft successfully separated from the rocket, entered the predetermined orbit, and successfully sent Zhai Zhigang, Wang Yaping, and Ye Guangfu into space. The flight crew was in good condition, and the launch was a complete success[48]。According to experts from the First Academy of China Aerospace Science and Technology Group, the Long March 2F carrier rocket has always played a special role as the "exclusive vehicle" for Chinese astronauts.After several technical improvements, the reliability of this type of rocket has been improved to 0.9894.In contrast, the reliability requirements of the launch vehicle for satellite launch and manned spacecraft launch are usually about 0.9 and 0.97 respectively. The improvement of the index of Long March 2F rocket not only breaks its own record again, but also makes the reliability of Long March 2F rocket at the forefront of the world[49]。
At 10:44 on June 5, 2022, the Long March 2F remote 14 carrier rocket carrying the Shenzhou 14 manned spacecraft was ignited and launched at Jiuquan Satellite Launch Center. About 577 seconds later, the Shenzhou 14 manned spacecraft was successfully separated from the rocket and entered the predetermined orbit. The flight crew was in good condition and the launch was a complete success[51]。
On August 5, 2022, China successfully launched a reusable test spacecraft using the Long March 2F carrier rocket at the Jiuquan Satellite Launch Center, which is the 18th launch mission of the Long March 2F carrier rocket[52]。
At 23:08 on November 29, 2022, Beijing time, the Long March 2F remote 15 carrier rocket carrying the Shenzhou 15 manned spacecraft ignited and launched at the Jiuquan Satellite Launch Center. About 10 minutes later, the Shenzhou 15 manned spacecraft successfully separated from the rocket and entered the predetermined orbit. The astronauts were in good condition and the launch was a complete success[53]。
At 9:31 on May 30, 2023 (Beijing time)Shenzhou 16Manned airshipLong March 2F Yao 16 carrier rocketThe launch was ignited at Jiuquan Satellite Launch Center. About 10 minutes later, the Shenzhou 16 manned spacecraft successfully separated from the rocket and entered the scheduled orbit. The astronauts were in good condition and the launch was a complete success.[55][57]
At about 1:34 on June 13, 2023, the second stage debris of Long March 2 F Yao 16 carrier rocket has reentered the atmosphere. The falling area is located in the surrounding sea area of 130.6 ° east longitude and 38.3 ° north latitude. Most devices were ablated and destroyed during re-entry.[58]
At 11:14 on October 26, 2023, Beijing time, the Long March 2F remote 17 carrier rocket carrying the Shenzhou 17 manned spacecraft ignited and launched at the Jiuquan Satellite Launch Center. About 10 minutes later, the Shenzhou 17 manned spacecraft successfully separated from the rocket and entered the predetermined orbit. The astronauts were in good condition and the launch was successful[61]。
On December 14, 2023, China successfully launched a reusable test spacecraft at Jiuquan Satellite Launch Center using the Long March 2F carrier rocket.[63]
At 20:59 on April 25, 2024, the Long March 2F Remote 18 carrier rocket carrying the Shenzhou 18 manned spacecraft ignited and launched at Jiuquan Satellite Launch Center. About 10 minutes later, the Shenzhou 18 manned spacecraft successfully separated from the rocket and entered the scheduled orbit.[65]
As a new generation of carrier rocket series in China, Long March 2F has strong adaptability and can meet the needs of China's domestic and foreign space launch markets in the 1930s and 1950s. It can upgrade China's carrier rocket, promote its industrialization process, and realize its leapfrog development, so as to comprehensively enhance the international competitiveness of China's carrier rocket[15]。
The reliability index of Long March 2F reaches 0.98, that is, the probability of failure in 100 launches cannot exceed twice, which is the highest among Chinese active rockets[41]。
The rocket can safely and reliably send the spacecraft into the predetermined orbit. At the same time, before flying out of the atmosphere, if there is a major failure, the astronauts can safely leave the failure danger zone according to the life-saving requirements.The Long March 2F rocket has successfully sent four Shenzhou unmanned spacecraft, Shenzhou 5, Shenzhou 6, Shenzhou 7 manned spacecraft, Tiangong 1 target aircraft, Shenzhou 8, Shenzhou 9, Shenzhou 10, Tiangong 2 space laboratory, and Shenzhou 11 manned spacecraft into the predetermined orbit of space[37]。As of June 17, 2021, the Long March 2F rocket has made 15 successful flights, with a 100% success rate, including launching five unmanned spacecraft, two space laboratories and seven manned spacecraft, and sending 12 or 17 astronauts into space[11][47]。（Comments on China Radio Network, China Aerospace, China Manned Space Engineering Network, China Academy of Launch Vehicle Technology）
