China's incredibly ambitious Tiangong space station: The complete guide

The Tiangong station represents the third phase of China’s crewed space program

The International Space Station is no longer the only research vessel orbiting the Earth.

After a successful launch on April 29, 2021, the core module of China’s Tiangong (translation: “celestial palace”) space station is now in orbit and has passed initial tests for rendezvous and docking maneuvers.

The China Manned Space Agency aims to complete the space station by the end of 2022, which will mean at least 10 more launches over the next 18 months to send up supplies.

These launches are happening in rapid succession: China is preparing to send the first shipment of cargo to the station just three weeks after the station’s launch, which will refuel the station and deliver supplies needed to keep astronauts alive in space.

The first crewed mission is scheduled for next month, in June 2021, and astronauts will live aboard the core module for three months. Subsequent crews will live on board for six months at a time.

The core module launched in April is named Tianhe, or “harmony of the heavens.” Later modules will permanently attach onto Tianhe to expand the station for scientific experiments, building out the station’s habitable space to 3,884 cubic feet. In comparison, the International Space Station has nearly four times the habitable space, calculated at 13,696 cubic feet.

The Tianhe core module, which is 16.6 meters long with a maximum diameter of 4.2 meters and a takeoff mass of 22.5 tonnes, is the largest spacecraft China has ever developed.

Image created by CGTN, a state-owned Chinese news service.

The Tiangong station represents the third phase of China’s crewed space program, which began in 1992. The first phase was to successfully send and return astronauts from space, and the second phase included smaller space stations used to test docking, spacewalks, and other necessities for a permanent installation. This Tiangong station is the permanently-crewed result of those tests and could stay operational for more than 15 years, with crew living onboard in 6-month shifts.

Over the next 18 months, Long March-5B heavy-lift rockets will bring the two experiment modules up to the station to complete the bulk of the station’s living space.

There will also be two cargo launches and two crew launches in 2021, and then the same in 2022. Cargo will be carried by Long March-7 medium-lift rockets, and crew will be carried by Long March-2F rockets.

Why did China build a space station?

While the International Space Station is an international research vessel, China is not a part of the 15-country partnership that owns and operates it.

This means that China has missed out on two decades of operational experience keeping humans alive in space, and has been unable to conduct bioengineering and materials research only possible in the low gravity of Earth’s orbit.

The exclusion stems from a 1998 Congressional commission that found information that American space companies had given to China for commercial purposes was being used to improve intercontinental ballistic missiles.

More than 10 years later, the policy was codified into law through the Wolf Amendment, which specified that NASA could not collaborate with China unless a law was passed specifically allowing it.

The space station strengthens the country’s “independent innovation capacity,” as Chinese President Xi Jinping said in 2018.

The space station gives China clout in scientific communities, but also serves as a point of national pride and international prestige, according to the Center for Strategic and International Studies’ ChinaPower publication.

It pulls the nation closer to equal footing with the international community’s space progress, which is now experienced enough to consider complex missions beyond Earth’s orbit. As an example, while China makes the Tiangong space station operational, the U.S. is readying the Artemis mission for prolonged research on the Moon.

A space station is also a diplomatic opportunity. In a 2018 statement, China expressed willingness to collaborate on scientific projects on board the planned space station with any UN member state.

That offer resulted in a program to bring nine international experiments on the Tiangong station, which range from studying tumors in space to researching high-efficiency solar cells.

China isn’t the only country looking to build its own space station. Russia has announced that it’s planning on building the Russian Orbital Space Station after its partnership agreement with the ISS expires in 2024. The United States has also begun looking beyond the ISS and is working with aerospace companies to potentially develop commercial space stations.

What will China’s space station look like?

The Tiangong space station will be in the form of a large “T,” reports to Scientific American, which interviewed Gu Yidong, chief scientist of the China Manned Space program.

The main Tianhe module is 18 meters long and will be able to support three astronauts for up to six months at a time. Two experiment modules will connect on each side of the main module, and each measure 14.4 meters long. One will be called Wentian, or “quest for the heavens” and the other will be Mengtian, or “dreaming of the heavens.”

Astronauts on the station will have about 1,700 cubic feet of living space in the Tianhe module, and the two experiment modules will add around 2,100 cubic feet more space. The livable space for astronauts will be broken up into six zones for “working, sleeping, sanitation, dining, healthcare, and exercise,” according to Chinese state media. Exercise equipment includes a treadmill built to work in space and an exercise bike.

The Tiangong station will be able to recycle air and water, including urine that is produced aboard the spacecraft. The urine recycling system is a key technology allowing China to keep astronauts in orbit for months at a time and is capable of extracting 80 percent of the water from the liquid waste at a rate of 2.5 liters per hour.

The reclamation of urine as drinking water borrows a page from American astronauts’ book, who drink water from urine, sweat, and breathed condensation. Russian astronauts, however, refuse to drink water reclaimed from urine. (Americans take the urine and recycle it for themselves.)

The Tianhe and Wentian modules both have external robotic arms, and the Mengtian module has an airlock for taikonauts to exit the station and maintain experiments on the outside of the station. The Tianhe module also features two ports on opposite ends, which will allow cargo and spacecraft docking. In total, the Tianhe has five docking ports.

China is also planning to add a telescope called Xuntian, or “survey of the heavens,” which will have a similar resolution as the Hubble Telescope, but with 300 times the field of view. The telescope will survey ultraviolet and visible light and have the ability to detect near-Earth asteroids. Crucially, it will be able to both dock with Tiangong and orbit independently, making it far easier to repair and refuel than the Hubble.

The rocket carrying Shenzhou-11 spaceship blasts off in Jiuquan Satellite Launch Center on October 17, 2016 in Jiuquan, China. China sent two astronauts to Tiangong-2 space station for a 33-day space mission.

Feature China / Barcroft Media via Getty Images / Barcroft Media via Getty Images

Tiangong is the third space station that China has launched into orbit. The first two were named Tiangong-1 and Tiangong-2 and were launched in 2011 and 2016, respectively. These earlier iterations of a single-module, habitable spacecraft welcomed small two-person crews, though for shorter durations than expected of the final Tiangong space station. A crew lived aboard the Tiangong-2 station for 33 days, which is still the longest time spent in space for Chinese astronauts, reports SpaceNews.

What research will be done on China’s space station?

The Tiangong space station will house 14 experiment racks and more than 50 locations on its exterior to test how materials endure the vacuum of space.

The experiments aboard Tiangong will focus on materials science and the effects of microgravity, according to Chinese state media. One test disclosed will include studying highly refractive glass that could replace diamonds in high-performance electronic equipment.

In addition to China’s own experiments aboard the station, nine international research projects have already been decided in collaboration with the United Nations.

Some of these projects are cutting-edge investigations into the nature of the universe, like the Polar-2 project, meant to detect faint Gamma-Ray Bursts (GRB) connected to gravitational waves. That project will build upon experiments conducted on China’s uncrewed Tiangong-1 station in late 2016, which measured 55 GRBs and then failed after 6 months, according to the Polar-2 research paper. This second attempt will give researchers even more data to classify different patterns of the mysterious radiation bursts.

What does the China space station mean for international politics?

The International Space Station could be retired as early as 2024 or 2028, and with no concrete plans for the United States to launch another station to orbit Earth, the Tiangong station could be the only option for long-term orbital experiments. While the United States has collaborated with 14 other countries to keep the ISS functional and plan scientific experiments, the Tiangong space station now allows China that same opportunity.

China’s approval of international experiments that will be brought aboard Tiangong has already meant scientific collaboration with Germany, Switzerland, Russia, India, Belgium, Japan, Norway, Holland, Mexico, Saudi Arabia, Italy, and Kenya.

Political tensions between the United States and China have created speculation that with this orbital monopoly, the Tiangong station could also secretly be used for military experiments or to otherwise support Chinese military operations. One US commander even suggested that the space station could be used to pick a satellite out of the sky and disable it, giving China an advantage if the satellite is critical to GPS or communications.

Dean Cheng, a senior research fellow at conservative think tank The Heritage Foundation, writes that the United States shouldn’t collaborate with China’s space program. He points to the Chinese space program’s close ties to the military, and a disregard for space safety when allowing rocket debris to fall uncontrolled after launches.

“Indeed, every launch facility, tracking facility, and mission control facility is a Chinese military facility,” Cheng writes. “Cooperating with the Chinese in space unavoidably means getting in bed with the Chinese military.”

Others disagree that excluding China from the United States space program is the best long-term strategy.

Marco Aliberti, a senior research fellow at the European Space Policy Institute, suggests that the United States’ refusal to collaborate with China encourages China to collaborate with Russia instead. That collaboration of two global superpowers would then certainly be interpreted as a threat to the United States, Aliberti says.

“A strong Sino-Russian partnership would clearly not be in the interest of the US and the West and its avoidance should indeed be one of the key drivers to guide the grand strategy of the new US administration,” he writes for the London School of Economics and Political Science.

The collaboration between the US and China ended due to a fear of China utilizing American rocket and satellite technology for military ends, professors Zhihui Zhang and Bruce Seely wrote in a history of satellite launch collaboration between the U.S and China. But that narrative was more a game of political positioning and a rising fear of China’s economy, rather than facts around whether China was arming itself for a war in space. Zhang and Seely conclude that instead of maintaining distance from China, the US space program could benefit more from working together again.

“A joint China-US mission, such as China participation in US space exploration or the U.S. involvement on the Chinese Space Station project, could open a new chapter in human space exploration,” they said.

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