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CSS (Chinese Space Station)

Launch   Mission Status     Tianzhou-2 supply mission   References

The Chinese large modular space station is a planned space station to be placed into LEO (Low Earth Orbit) between 340 and 450 km above the surface. The planned Chinese Space Station will be roughly one-fifth the mass of the ISS (International Space Station) and about the size of the decommissioned Russian Mir space station. The Chinese station is expected to have a mass between 80 and 100 tons. Operations will be controlled from the Beijing Aerospace Command and Control Center in China. The planned launch date of the core module, the Tianhe (“Harmony of the Heavens”), is 2021. In 2017, the Chinese launched the Tianzhou-1 ("Heavenly Vessel") cargo spaceship, which is based on the Tiangong 1 and 2 space laboratories. 1)

China formally launched its manned space program, known as Project 921, in September 1992. Chief objectives of the multi-phase Project 921 include achieving human spaceflight and developing and operating what Wu Ping, then-Deputy Director of China’s Manned Space Agency (CMSA), called a “permanent” manned Chinese space station. 2)

A critical aspect of Project 921 was the development of the Tiangong (“Heavenly Palace”) space laboratories that served as critical testbeds for gaining the technical know-how for operating the CSS. The 8.5 metric ton Tiangong-1 launched in September 2011 and enabled Chinese astronauts – or “taikonauts” – to practice rendezvous and docking maneuvers and carry out short-term missions in space. China lost communication with the space module in March 2016, and on April 2, 2018 the Tiangong-1 plunged through Earth’s atmosphere, scattering debris over the South Pacific.

Chinese engineers applied lessons from the Tiangong-1 to improve the design of its successor, the Tiangong-2, which launched in September 2016. The Tiangong-2 featured a greater capacity for scientific experimentation and was therefore described by Wu Ping as a laboratory “in the true sense of the word.” According to China’s 2016 white paper on space activities, the Tiangong-2 offered a platform for China to master key capabilities, such as cargo transport and replenishment, necessary for operating a permanent space station.

The advantages of developing space capabilities are manifold. Satellites facilitate military and civilian communications. Human spaceflight garners international prestige, while also providing opportunities for cutting-edge research. Experiments conducted in space have resulted in numerous breakthroughs that have been used to address medical, environmental, and technological challenges back on Earth.

Due to improvements in living quarters and life-support infrastructure, the module was able to host the two-man Shenzhou-11 crew for 30 days in late 2016. This marked China’s longest crewed mission to date. China successfully de-orbited the Tiangong-2 in July 2019. A third Tiangong space lab, capable of supporting three taikonauts for 40-day intervals, was planned but the program was later cancelled in favor of skipping to the development of a more advanced space station.

Designing the Chinese Space Station

Building on the success of the Tiangong missions, China constructed the core module of the CSS. Dubbed the Tianhe-1 (“Harmony of the Heavens-1”), the core module is 18.1 meters long and has a mass of 22 metric tons. The module was originally planned for entry into orbit sometime in 2018, but officials announced in March 2018 that the launch would be delayed. Reports indicate the delay was due to a failed launch in 2017 of the heavy-lift Long March 5 rocket that is needed to lift the module into orbit. On April 29, 2021, a Long March 5B rocket successfully launched the Tianhe-1 into Earth’s orbit, nearly three years behind the original schedule.

The core module will be joined by the Tianzhou-2 cargo and supply spacecraft, which will dock with the Tianhe-1 to deliver propellant as well as supplies for the taikonauts who will eventually live on the CSS. The Tianzhou-2 will have a mass of around 13.5 metric tons, with a cargo mass of around 6.5 metric tons. The spacecraft will launch on a Long March 7 medium-lift rocket, likely in May 2021.

With the core module deployed and stocked, China will launch three taikonauts to live on the CSS. The launch is expected to take place in June 2021. This crewed mission, named Shenzhou-12, will be China’s seventh, and the first since the Shenzhou-11 mission in 2016. There are currently a total of four crewed missions planned, with 12 taikonauts in training to live on the CSS.

In addition to the core module, the station’s basic configuration will eventually also consist of two experiment modules – the Wentian (“Quest for the Heavens”) and Mengtian (“Dreaming of the Heavens”) – permanently docked opposite each other in a T-shape structure. Each experiment module will have roughly the same length (14.4 meters) and mass (22 metric tons). Both modules are expected to be launched in 2022.


Figure 1: Scale rendering of the Chinese Large Modular Space Station (image credit: China)

Chinese engineers plan to outfit the CSS with a number of features. The Tianhe core has five docking ports, as well as a robotic arm and internal racks for experimentation. The Wentian will also feature modular storage racks and a robotic arm, while the Mengtian will have a docking port to interface with visiting spacecraft, repair vehicles, and support modules. A space telescope, the Xuntian (“Heavenly Cruiser”), may also launch into orbit near the Chinese Space Station around 2024. It is expected to have a field of view 300 times the size of NASA’s Hubble Space Telescope.

If successfully completed, the CSS will be roughly one-sixth the mass of the International Space Station (ISS) and half the size of the decommissioned Russian Mir Space Station. The Chinese station is expected to have a total mass between 60 and 70 metric tons, while the ISS has a mass over 420 metric tons, and Mir had a mass of approximately 130 metric tons.


Figure 2: Overview of US, Chinese and Russian space stations (image credit: China Power)

Development status

• June 15, 2021: The first crew for China's new space station prepared to blast off this week for the latest step in Beijing's ambitious program to establish itself as a space power. 3)


Figure 3: A Long March-2F rocket will carry the first crew to China's new space station (image credit: China)

- The mission is China's first crewed spaceflight in nearly five years, and a matter of prestige for the government as it prepares to mark the 100th birthday of the ruling Communist Party on July 1 with a propaganda blitz.

- A Long March-2F rocket carrying three astronauts in the Shenzhou-12 spacecraft is slated to lift off from a base in northwest China's Gobi desert on Thursday, according to experts with knowledge of the matter.

- They plan to spend three months on the Tiangong station, China's longest crewed space mission to date, with spacewalks among their tasks.

- The astronauts will aim to "get their new home in space kitted out and ready to use," said Jonathan McDowell, an astronomer at the Harvard Smithsonian Center for Astrophysics. - "It's a practical goal rather than a groundbreaking one."

- The Long March rocket, with the Shenzhou craft attached, was moved to the launch pad at the Jiuquan Satellite Launch Center last week, according to the Chinese space agency.

- Shenzhou-12 will dock with the main section of the Tiangong station, named Tianhe, which was placed in orbit on April 29. A cargo craft last month transported fuel, food and equipment for the crewed mission.

- Another 11 missions are planned over the next year and a half to complete the construction of Tiangong in orbit, including the attachment of solar panels and two laboratory modules.

- Three of those missions will carry astronauts for crew rotation.

- "Keeping the station up and running smoothly involves much detailed and complicated work, as we saw on the International Space Station during its early days," said Chen Lan, an analyst at GoTaikonauts, which specializes in China's space program.

- Once completed, Tiangong will have a mass of around 90 tons and is expected to have at least a 10-year lifespan, according to the Chinese space agency.


Figure 4: China's plan to build a space station (image credit: China State Media/

• April 30, 2021: Commercial enterprises will have opportunities to take part in the construction and operation of the nation's space station, according to a senior space official. 4)

- Hao Chun, head of the China Manned Space Agency, told China Daily in an interview earlier this month that his agency, which administers the space station program, will take advantage of private space companies' technologies and capabilities to help State-owned contractors build and maintain the station.

- "Actually, we have already started inviting private companies to offer their solutions to us. For instance, we invited bids for new concepts of cargo transportation to our space station and then received proposals from more than 10 private enterprises," Hao said. "Next, we will review those proposals and select and support the good ones."

- If the selected companies prove to be competent and qualified, the agency will consider commissioning them to fulfill cargo transportation missions for the station, according to him.

- Currently, China has only one type of cargo spaceship-the Tianzhou, which was developed by State-owned space giant China Aerospace Science and Technology Corp. Tianzhou 1 performed resupply and refueling tests with the Tiangong II space laboratory in 2017, while Tianzhou 2 is scheduled to be launched in the coming months to dock with the core capsule of the space station.

- "The participation of commercial space enterprises will give us greater flexibility and offer us more convenience in terms of the operation and maintenance of the space station, and it will also help us reduce our overall costs," Hao said, also suggesting that private companies should understand the space station program's demands and look into available opportunities to make the best use of their expertise.

- The official also said that the rapidly expanding commercial space sector will become a major driving force for China's space industry.

- In the wake of the intensifying contest in the global space arena, China has realized that it is necessary to introduce new players to stimulate innovation and competition and to fill in market gaps left by established contractors.

- As an important part of his endeavor to strengthen China's space industry, President Xi Jinping has requested that the long sheltered industry open its doors to private enterprises and capitalize on their participation to boost sustainable growth.

- Meanwhile, several government departments have published policies and guidelines that encourage private enterprises to take part in space-related businesses.

- Due to the government's support and thriving business demands, dozens of domestic private space companies have emerged and obtained some market share in the carrier rocket and satellite industries.

• April 23, 2021: China is set to launch the first module for its own space station next week after rolling out a Long March 5B rocket at Wenchang spaceport late Thursday. 5)


Figure 5: Rollout of the first Long March 5B to the pad at Wenchang, South China in April 2020 (image credit: CASC)

- The 53.7-meter-long Long March 5B is now expected to launch the 22-ton Tianhe space station core module around April 29, although authorities have not officially released a launch time.

- The launch will mark the beginning of an intense construction phase for the three-module space station. China plans 11 major launches of modules, cargo and crewed spacecraft across 2021-22.

- The Chinese space station was first envisioned in 1992 when China approved its Project 921 to develop human spaceflight capabilities. China sent its first astronaut, Yang Liwei, into orbit in October 2003.

- The Long March 5B was transferred to the launch area early Friday local time. The rocket was transferred from a vertical integration building via a 2.7-kilometer track, with the transfer process taking about two and a half hours.

- Encased in the payload fairing atop the rocket is the 16.6-meter-long, 4.2-meter-diameter Tianhe core module along with a docking hub. Tianhe and the Long March 5B arrived at Wenchang in February for assembly and integration.

- Tianhe, meaning “harmony of the heavens”, is planned to be inserted directly into a low Earth orbit with an apogee of around 370 kilometers and inclined by 41 degrees.

- The three-module, 66-metric-ton space station will host three astronauts for six month rotations. Planned experiments include international projects in the areas of astronomy, space medicine, space life science, biotechnology, microgravity fluid physics, microgravity combustion and space technologies.

- The Tianhe module will provide regenerative life support and living space for three astronauts as well as propulsion to maintain the orbit of the entire complex.


Figure 6: The Tianhe core module and docking hub of the Chinese Space Station [image credit: CMSA (China Manned Space Agency)]

• September 11, 2019: The first module for China’s planned space station has passed a final review, but the project continues to suffer launch vehicle-related delays. 6)

- The China Manned Space Agency (CMSA) announced Sept. 6 that the 20-metric-ton ‘Tianhe’ module design and prototype had passed final reviews Sept. 2. The flight model would be manufactured in the near future.


Figure 7: A Tianhe core module of the Chinese Space Station undergoing testing in 2018 (image credit: CCTV/Framegrab)

- Tianhe (‘Harmony of the Heavens’) is the core module for the Chinese Space Station (CSS) and will control the station’s orbit and attitude and function as the main astronaut quarters.

- When Tianhe will launch is still unknown. According to previous official statements the first of three modules for the space station was to be launched in 2020, with the complex to be completed by ‘around 2022’.

- The ‘around 2022’ time frame had not changed despite ongoing delays in readying the launch vehicle required for the project, suggesting a more compressed schedule.

- The timeline for completion has however now shifted to ‘2022-2024’, according to Faren Qi, chief designer of the Shenzhou spacecraft which has facilitated China’s human spaceflight missions.

- Qi provided media with the new timeline at a satellite navigation and location services conference in Zhengzhou, Henan Province, Sept. 10.

- Qi added that the first flight of the CSS project would be the test launch of the Long March 5B, now expected in the first half of 2020. If successful, that launch would clear the way for launch of the Tianhe module.

- The Long March 5B test flight will carry an uncrewed version of a next generation spacecraft for human spaceflight. The successor to the 7.8-metric-ton Shenzhou will feature partial reusability and have a maximum launch mass of around 23 tons.

- Qi stated that the new spacecraft would be modular in design and versatile in order to meet the demands of Chinese space development. The 9-meter-long, two-module spacecraft will be capable of missions beyond low Earth orbit, including lunar and deep space missions.

- This and other major missions have however been delayed due to problems with China’s Long March 5 heavy-lift rocket.

Launch: China successfully launched a 22-metric-ton module Tianhe on 29 April 2021 at 03:23 UTC (11:23 p.m. EDT on 28 April (Wednesday), beginning an intense period of missions for constructing the nation’s own space station. 7)

Orbit: The CSS will be operated in LEO at an altitude between 340 and 450 km with an inclination of ~42º.

A Long March 5B heavy-lift rocket lifted off from the coastal Wenchang spaceport. The Tianhe space station core module separated from the first stage after 490 seconds of flight.


Figure 8: Liftoff of the Long March 5B rocket carrying the Tianhe core module for the Chinese Space Station (image credit: CCTV/framegrab)

Solar array deployment occurred just over an hour after launch. Shangfu Li, chief commander of the China Manned Spaceflight Program, announced launch success shortly after.

Tianhe, or “harmony of the heavens”, is now expected to raise its orbit to around 370 kilometers above the Earth. The uncrewed Tianzhou-2 cargo spacecraft is now expected to rendezvous and dock with Tianhe in mid-late May, ahead of the visit of three astronauts aboard Shenzhou-12 in June.

Tianhe, a much larger upgrade on China’s smaller, 8-ton Tiangong testbed space labs, is equipped with a multi-docking hub to facilitate construction of the space station and allow crew to embark on extravehicular activities.

The 16.6-meter-long, 4.2-meter-diameter Tianhe will provide regenerative life support and the main living quarters for astronauts as well as propulsion to maintain orbital altitude.

The construction phase of China’s space station begins nearly 30 years after the project was first approved, back in 1992.

Across this period China has developed and tested the Shenzhou spacecraft and Long March 2F for human spaceflight, Tianlian relay satellites, rendezvous and docking technologies, refueling in microgravity, new launch vehicles and the coastal Wenchang Satellite Launch Center in order to proceed with the project.


Figure 9: Artist impression of the future Chinese Space Station (image credit: CMSA)

The CSS (Chinese Space Station) is expected to operate in orbit for at least ten years. Experiment modules named Wentian and Mengtian, expected to launch in 2022, will host a plethora of experiments in areas including astronomy, space medicine, space life science, biotechnology, microgravity fluid physics, microgravity combustion and space technologies.

International science payloads and experiments have also been selected for a journey to the CSS through cooperation between the United Nations Office for Outer Space Affairs (UNOOSA) and the China Manned Space Agency (CMSA).

China had expressed interest in joining the International Space Station project but membership was effectively denied by U.S. policy towards China’s space programs.

The launch of the Tianhe core module was delayed by the 2017 launch failure of the second Long March 5. The saw the postponement of the test launch of the Long March 5B variant for low Earth orbit launches while issues with the YF-77 liquid hydrogen-liquid oxygen engine for the core stage were isolated and remedied.

The CSS will also be joined in orbit by the Xuntian optical module, a co-orbiting, Hubble-class space telescope. The space telescope will have a 2-meter-aperture comparable to Hubble but feature a field of view 300 times greater, allowing 40 percent of the sky to be surveyed across a decade.

Xuntian will be capable of docking with the CSS for maintenance and repairs. The space station itself could also be expanded from three to six modules, using modules developed as backups.

Mission status

• June 15, 2021: Highly efficient power supply has kept the combination of the Tianzhou-2 cargo craft and China's space station core module Tianhe operating stably. 8)

- China sent into space the Tianhe module on April 29, kicking off a series of key launch missions that aim to complete the construction of the space station by the end of 2022.

- The country launched Tianzhou-2 on May 29, which successfully docked with Tianhe in about eight hours to deliver supplies, equipment and propellant.

- Both the core module and cargo craft are equipped with independent power supply systems. After docking, the two systems can form a connected grid and achieve mutual transmission of electric power.

- "The two independent systems work like two smartphones," said Yu Lei, an engineer in charge of power supply to the Tianzhou-2 project. "They can undergo both separate and mutual charging."

- When docking with the space station, Tianzhou-2 is in sleep mode and has relatively lower power demand. Its solar panels can provide abundant power most of the time, and the surplus is stored to be used for astronaut activities and scientific research that requires higher energy consumption.

- "Its solar panels not only fulfill the power demand of Tianzhou-2 directly, but also charge its batteries," said Wang Zhenxu, a designer of the power supply system of the Tianzhou-2 project.

- Researchers estimate that it takes 91 minutes for the space station to go around Earth in the low-Earth orbit, during which it can receive sunlight for about 54 minutes. The solar panels thus experience the light-shade cycle about 16 times every day.

- The three sets of lithium ion batteries power the entire cargo craft when the combination enters the shadow areas. The solar panels work again after it moves into the sunlight, and continue supplying power and charging.

- The core module Tianhe is powered by third-generation flexible GaAs (gallium arsenide) solar panels, which provide high power output, are light, small when folded, have long in-orbit life, and can be repeatedly folded and unfolded.

- The thickness of a solar panel is less than one millimeter, only half of the weight per unit area of the traditional solar arrays.

- The power area of Tianhe's solar panels covers 80 square meters, which can provide 20 KW power to the core module, said Yu Hui, designer of the solar panels.

- The researchers carried out a large number of ground simulation tests to verify the environmental protection technology used in the solar panels to help them endure almost 90,000 high and low temperature alternating cycles ranging from 100 to minus 100 degrees Celsius in orbit as well as the complex space environment.

- The design life of the solar panels is up to 15 years, and they can work effectively for the space station project, Yu Hui said.

• May 19, 2021: NASA Administrator Bill Nelson issued the following statement Wednesday after the China National Space Administration’s release of the first photos from the Zhurong Mars rover: 9)

- “Congratulations to the China National Space Administration on receiving the first images from the Zhurong Mars rover!” Nelson said. “As the international scientific community of robotic explorers on Mars grows, the United States and the world look forward to the discoveries Zhurong will make to advance humanity’s knowledge of the Red Planet. I look forward to future international discoveries, which will help inform and develop the capabilities needed to land human boots on Mars.”

- CNSA’s successful landing of the Zhurong rover last week makes it only the second nation to ever land successfully on Mars. Zhurong joins active NASA missions – the Curiosity and Perseverance rovers and Insight Lander – in exploring the surface of the Red Planet.

• May 19, 2021: China's core space station module Tianhe has recently completed its platform function tests and entered the orbit to rendezvous and dock with the Tianzhou-2 cargo spacecraft, according to the China Manned Space Agency (CMSA) on Tuesday. 10)

- The core module, which was sent into orbit on April 29, has recently completed platform function tests for rendezvous and docking, astronaut stay and the mechanical arms, as well as in-orbit performance checks for space application project equipment.

- The CMSA said the core module's various functions are normal. It is operating in good condition and has entered the orbit for rendezvous and docking. It will continue its preparations for rendezvous and docking with the Tianzhou-2 cargo spacecraft.

• May 9, 2021: Debris from a large Chinese rocket stage fell into the Indian Ocean late 8 May EDT as people around the world watched for signs of the fiery reentry event in the skies. 11)

- Remnants from the roughly 30-meter-long, five-meter-wide empty core stage of the Long March 5B fell into the Indian Ocean at 10:24 p.m. EDT (10:24 a.m. Beijing Time) close to longitude 72.47º east and latitude 2.65º north, China’s human spaceflight agency, CMSEO (China Manned Space Engineering Office), announced.

- Data from the U.S. Space Force’s 18th Space Control Squadron space tracking later confirmed reentry occurred at approximately 10:15 p.m. EDT over the Arabian Peninsula, adding that “It is unknown if the debris impacted land or water.”

- Sightings and videos were posted on social media platforms May 8 as the rocket began its last orbits around the Earth.

- The Long March 5B successfully launched China’s first space station module directly into low Earth orbit April 28 EDT.

- Unusually for a first stage the rocket body had entered and remained in orbit following launch, and would become one of the largest instances of uncontrolled reentry of a spacecraft in decades. While the 22.5-ton Tianhe core module used its own propulsion to raise its orbit, the orbit of the first stage began to decay due to atmospheric drag.

- The size of the stage, travelling at 7.8 km/s and orbiting once every 90 minutes between 41.5º north and 41.5º south latitude, quickly became a matter of both space industry and public interest.

• May 4, 2021: A large rocket stage which launched China’s first space station last week is likely to reenter the atmosphere around May 8 according to early space tracking predictions. 12)

- U.S. Department of Defense Spokesperson Mike Howard in a statement May 4 said that “U.S. Space Command is aware of and tracking the location of the Chinese Long March 5B in space, but its exact entry point into the Earth’s atmosphere cannot be pinpointed until within hours of its reentry, which is expected around May 8.”

- “Until then, the 18th Space Control Squadron will be offering daily updates to the rocket body’s location on beginning May 4. We will provide additional information as it becomes available,” the statement read.

- The launch of the Long March 5B late April 28 EDT successfully placed the 22.5-metric-ton Tianhe core module into orbit. However, the roughly 30-meter-long, 5-meter-diameter Long March 5B first stage also reached orbital velocity rather than fall with a predetermined area downrange.

- The empty rocket body is now in a 162 by 306-kilometer altitude orbit according to U.S. 18th Space Control Squadron space tracking, down from an initial 170 by 372-kilometer orbit.

- Without the ability to restart its engines the core stage will be dragged towards Earth by increasing collisions with molecules in the Earth’s atmosphere. Atmospheric fluctuations and other variables and the high velocity of the stage mean that accurate predictions of when and where the stage will reenter are not possible until a few hours before the event.

- The Long March 5B core stage’s orbital inclination of 41.5 degrees means the rocket body passes a little farther north than New York, Madrid and Beijing and as far south as southern Chile and Wellington, New Zealand, and could make its reentry at any point within this area.

Tianzhou-2 space station supply mission

On 17 May 2021, China is set to launch the Tianzhou-2 space station cargo mission this week after rollout of a Long March 7 rocket at the Wenchang spaceport. 13)


Figure 10: Rollout of the third Long March 7 rocket carrying the Tianzhou-2 spacecraft at the Wenchang launch site (image credit: CMSA)

The Rollout took place on 16 May (Beijing time) at the coastal Wenchang satellite launch center. Final checks, rehearsals and pre-launch preparations will take place ahead of an instantaneous launch window expected around May 20 local time.

The roughly 13-metric-ton Tianzhou-2 cargo spacecraft will head to low Earth orbit to rendezvous and dock with China’s Tianhe space station core module.

Tianzhou-2 will transfer propellant to Tianhe for maintaining its orbit and also to deliver supplies to support crewed future missions.

Three astronauts are set to launch for Tianhe on the three-month Shenzhou-12 mission in June. The mission will launch on a Long March 2F rocket from Jiuquan in the Gobi Desert.

Tianzhou-2 will carry 4.69 tons of cargo in a pressurized segment and 1.95 tons of propellant, according to CMSA (China Manned Space Agency.

The 22.5-ton Tianhe space station core module launched on 29 April 2021 at 03:23 UTC on a Long March 5B rocket and is now in an orbit of 360 x 385 km with an inclination of 41.5º. The core stage of the Long March 5B made an uncontrolled reentry May 8 after intense media coverage.


Figure 11: The Tianzhou-2 spacecraft undergoing testing (image credit: CAST)

Tianzhou-2 is the second of 11 launches scheduled for 2021 and 2022 to construct China’s 66-ton, three-module orbital outpost (CSS).

A Long March 2F rocket and Shenzhou spacecraft will also be on standby at all times at Jiuquan to perform emergency rescue missions to the space station.

China launched Tianzhou-1 in 2017 to dock with the Tiangong-2 space lab. That mission tested and verified technologies for fuel transfer in microgravity, a necessary capability for maintaining the orbit of the Chinese space station.

The Long March 7 is one of a number of new-generation kerolox and hydrolox rockets developed by China over the past decade. These include the Long March 5, 6, 7 and 8 series of rockets.

It is powered by 120-ton-thrust YF-100 and 18-ton-thrust YF-115 engines burning kerosene and LOX on the first, second and booster stages. The first stage will not reach orbital velocity and will fall within a predefined area in the ocean.


Figure 12: A view inside the cargo section of the Tianzhou-1 cargo spacecraft (image credit: CCTV/framegrab)

Launch: On 29 May 2021, a Long March 7 medium-lift rocket lifted off from the coastal Wenchang spaceport on Hainan Island at 12:55 UTC [8:55 Beijing time = CST (China Standard Time)]. The roughly 13-metric-ton Tianzhou-2 cargo spacecraft entered its intended orbit and deployed its solar arrays at 13:17 UTC, the China Aerospace Science and Technology Corp. (CASC) confirmed within an hour of liftoff. 14)


Figure 13: A Long March 7 carrying the Tianzhou-2 spacecraft lifts off from Wenchang ahead of an orbital docking with Tianhe (image credit: CASC)

The uncrewed Tianzhou-2 spacecraft completed automated rendezvous and docking maneuvers with Tianhe at 17:01 CST (22:01 UTC) on 29 May 2021.

Tianzhou-2 is tasked with delivering propellant and supplies ahead of a first crewed mission to Tianhe in June.

Tianhe, the first module for China’s space station, launched late April 28 and passed on-orbit testing May 18, according to the China Manned Space Engineering Office (CMSEO).

Tianzhou-2 matched its 343 by 371-kilometer orbit for rendezvous. Now docked, Tianzhou-2 will conduct an automatic transfer of 1.95 tons of propellant to the 22.5-ton Tianhe module.

It will remain docked to the station module to support the upcoming crewed Shenzhou-12 mission in June. Tianzhou-2 holds 4.69 tons of cargo in a pressurized segment, including food for the Shenzhou-12 crew for three months. It also carries extravehicular activity space suits and other supplies.

The 16.6-meter-long, 4.2-meter-diameter Tianhe (“harmony of the heavens”) will provide regenerative life support and the main living quarters for astronauts as well as propulsion to maintain orbital altitude.

Tianzhou-2 was first expected to launch May 19 but the mission was delayed due to “technical reasons,” according to CMSEO. It is unknown how the delayed Tianzhou-2 docking will impact the Shenzhou-12 mission expected around June 10.

Tianzhou-2 is the second launch of 11 missions planned for the construction phase of the three-module Chinese space station across 2021 and 2022.

Experiment modules named Wentian and Mengtian are expected to launch in 2022. The pair will host a plethora of experiments in areas including astronomy, space medicine, space life science, biotechnology, microgravity fluid physics, microgravity combustion and space technologies.

The Chinese space station is expected to operate in orbit for at least ten years. It will be joined in orbit by the Xuntian optical module, a co-orbiting Hubble-class space telescope. The space telescope will have a 2-meter-aperture comparable to Hubble but feature a field of view 300 times greater, allowing 40 percent of the sky to be surveyed across a decade.

1) ”Chinese large modular space station,” Wikipedia, URL:

2) China Power Team,” What’s Driving China’s Race to Build a Space Station?," China Power, 7 December 2016, updated 29 April 2021,

3) Ludovic Ehret and Poornima Weerasekara, ”China ready to launch first crew to new space station,”, 15 June 2021, URL:

4) ”Private firms expected to help build space station,” Space Daily, 30 April 2021, URL:

5) Andrew Jones, ”China rolls out Long March 5B rocket for space station launch,” SpaceNews, 23 April 2021, URL:

6) Andrew Jones, ”Chinese space station core module passes review but faces delays,” SpaceNews, 11 September 2019, URL:

7) Andrew Jones, ”China launches Tianhe space station core module into orbit,” SpaceNews, 29 April 2021, URL:

8) China Focus: ”Effective power supply energizes China's space station project,” Xinhuanet, 15 June 2021, URL:

9) ”NASA Statement on China’s Zhurong Mars Rover Photos,” NASA Press Release 21-067, 19 May 2021, URL:

10) ”China's core space station module Tianhe completes in-orbit tests,” Space Daily, 19 May 2021, URL:

11) Andrew Jones, ”Long March 5B falls into Indian Ocean after world follows rocket reentry,” Space News, 9 March 2021, URL:

12) Andrew Jones, ”Chinese rocket stage predicted to reenter atmosphere around May 8,” SpaceNews, 4 May 2021, URL:

13) Andrew Jones, ”China rolls out rocket for Tianzhou-2 space station supply mission,” SpaceNews, 17 May 2021, URL:

14) Andrew Jones, ”Tianzhou-2 docks with China’s space station module,” SpaceNews, 29 May 2021, URL:

The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: ”Observation of the Earth and Its Environment: Survey of Missions and Sensors” (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (

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