Core capsule of space station launched

Sixty years after Yuri Gagarin undertook mankind's first space journey, China launched the core capsule of its space station on Thursday morning, formally embarking on the construction of one of the world's largest and most sophisticated space-based facilities.

President Xi Jinping sent a letter after the launch, extending congratulations and greetings to those involved in the landmark mission.

Xi, who is also general secretary of the Communist Party of China Central Committee and chairman of the Central Military Commission, said that building the station, which will also serve as a space-based national laboratory, is a significant goal in China's manned space endeavor and a major project that will help to push China toward being a strong power of science, technology and space.

The successful launch of the core capsule marked the commencement of the space station's construction, he said.

Xi encouraged mission workers to continue striving for the ultimate success of the space station program.

As the countdown ticked down to zero at 11:23 am at the Wenchang Space Launch Center in Hainan province, 10 engines at the bottom of a Long March 5B heavy-lift carrier rocket roared to life, generating a thrust power of 1,068 metric tons to lift the 18-story-tall vehicle through thick rain clouds covering the coastal city of Wenchang.

After flying more than eight minutes, the rocket successfully put the 22.5-ton capsule, the biggest and heaviest spacecraft China has ever constructed, in a low-Earth orbit about 400 kilometers above the Earth, settling the first piece of the country's space station in place.

The capsule's solar panels unfolded at 12:36 pm and began generating power for the spacecraft.

Premier Li Keqiang and member of the Secretariat of the CPC Central Committee Wang Huning, both also members of the Standing Committee of the Political Bureau of the CPC Central Committee, and a group of high-ranking leaders witnessed the launch at the Beijing Aerospace Control Center in the capital's northwestern suburbs.

China's most adventurous space endeavor, the multimodule space station, named Tiangong, or Heavenly Palace, will have three main components－a core module attached to two space laboratories－with a combined weight of nearly 70 tons.

The core capsule, named Tianhe, or Harmony of Heavens, is 16.6 meters long and has a diameter of 4.2 meters. The craft's weight is equal to the combined weight of 15 standard-size automobiles. It has three parts－a connecting section, a life-support and control section and a resources section.

The capsule will be central to the space station's future operations, given that astronauts will live there and control the entire station from inside. It will also be used to host scientific and technological experiments.

Thursday's launch marked the second flight of a Long March 5B, the most powerful Chinese rocket when it comes to carrying capacity to low-Earth orbit.

With a core stage and four side boosters, the rocket has a liftoff weight of 849 tons and is capable of putting a 25-ton payload into orbit near Earth.

It is now the only rocket in China that can launch Tiangong's heavyweight components.

The launch vehicle is so big that each of its side boosters is nearly 28 meters tall－the height of a nine-story building－and 3.35 meters wide. Each has a thrust power of 240 tons.

To hold huge spacecraft, the rocket has China's largest payload fairing－a type of nose cone used to protect a spacecraft payload against dynamic pressure and aerodynamic heating during launch－at 20.5 meters tall and 5.2 meters wide.

Long March 5B made its debut flight in May 2020 at the Wenchang space complex, deploying the prototype of China's new-generation manned spacecraft, an experimental cargo retrieval craft, and more than 10 experimental payloads into low-Earth orbit.

Future arrangements

Construction of the space station marks the beginning of the third stage of China's manned space program, which was approved by the government in 1992.

The program's first two stages had concluded successfully with six manned spaceflights and two experimental space lab missions.

After the core capsule was launched, astronauts on the Shenzhou XII and XIII missions and two cargo ships will be launched within a few months to prepare the module for docking with other parts of the station.

Next year, Tiangong's two space labs, two manned missions and two robotic cargo flights will be made to continue construction of the station.

The entire station is expected to become fully operational around the end of 2022 and is set to work for about 15 years, mission planners have said.

Once completed, the facility will be capable of docking with multiple crewed and cargo spaceships at the same time and will also be able to link with foreign spacecraft if they have a Chinese-standard docking hatch.

Upon its completion, the station will be manned regularly by groups of three astronauts in periods lasting several months. During hand-overs to new three-astronaut groups, the station will accommodate up to six astronauts.

In addition to its own components, the station will also be accompanied by an optical telescope that will be lifted after the station's completion to fly together with it, according to mission planners.

Currently, astronauts taking part in the coming four manned spaceflights are undergoing intensive training and preparation, Ji Qiming, a senior mission manager at the China Manned Space Agency, said at a news conference on Thursday afternoon at the Wenchang center.

The Tianzhou 2 cargo ship was transported to the Wenchang facility in mid-April, and the Shenzhou XII manned spacecraft arrived in the Jiuquan Satellite Launch Center in northwestern China at the same time.

Comfortable environment

Yang Hong, the core capsule's chief designer at the China Academy of Space Technology, said the Tianhe allows for astronauts' long-term stay and their extravehicular activities, which will be needed for them to assemble the station, examine its external condition or repair broken parts.

About 50 cubic meters are available inside the vehicle for occupants' living and work activities－much more room than in the previous Chinese manned spacecraft. Once the two space labs are connected with the capsule to complete the Tiangong station, astronauts will have as much as 110 cubic meters in their usable space, he said.

By comparison, the usable space in the Shenzhou-series crewed spaceship is about 7 cubic meters.

Yang added that outside the capsule are large mechanical arms that will assist astronauts in assembling, operating and maintaining the station.

Zhang Hao, a senior designer at the academy who took part in the capsule's development, said that compared with previous Chinese manned spaceships, the capsule features better living conditions for astronauts.

"There are separate quarters for working, sleeping, personal hygiene, dining, healthcare and physical exercises," Zhang said. "Each astronaut will have their own bed and will share a dedicated washroom, which appears in a Chinese spacecraft for the first time. We installed many appliances inside the craft to make their stay easier, such as an air conditioner, microwave oven, refrigerator, water dispenser and treadmill."

Each astronaut will have a specially designed mobile phone capable of not only making calls between astronauts and with people on the ground, but also remotely controlling the capsule's internal apparatus, according to Zhang.

Luo Bin, a senior designer at the Shanghai Academy of Spaceflight Technology who participated in the program, said solar panels are one of the capsule's technical highlights.

"The panels were made of highly flexible materials," Luo said. "That means that even though their overall area is as much as 134 square meters, once they are folded, the thickness is similar to that of an ordinary book."