China on Thursday sent into space the core module of its space station, starting a series of key launch missions that aim to complete the construction of the station by the end of 2022.

The core module, named Tianhe, was carried into space by a Long March-5B Y2 carrier rocket launched from the Wenchang Spacecraft Launch Site on the northeastern coast of south China's Hainan Province.

The rocket blasted off at 11:23 a.m. (Beijing time). The Tianhe core module separated off the carrier rocket 494 seconds later and entered its planned orbit. At 12:36 a.m., its two solar array wings started functioning after smoothly unfolding, signifying a complete success of the launch.

Tianhe will act as the foundational module for China's first low-Earth orbital space station named Tiangong, which means "heavenly palace" in Chinese. 

What will the space station look like?

The space station will form a T-shape with Tianhe at the center and two lab capsules, Wentian and Mengtian, on each side, according to Zhou Jianping, chief designer of China's manned space program.  

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.

It will be the management and command center of the whole space station, which will provide propulsion to maintain the orbit of the complex and control its internal working conditions. It will also be the main living place of the coming astronauts, where they can also conduct planned scientific and technological experiments.

The core module has a habitable space of about 50 cubic meters. When the two lab capsules are in place, the complex will have a total living space of 110 cubic meters, according to Zhou. 

The core module has two berth ports that can connect with the two lab capsules and three docking ports for any cargo vessel, manned spaceship and other spacecraft to come. It also has an exit for astronauts to conduct extravehicular activities.

Wentian lab capsule and Mengtian lab capsule are similar to the core module in length, size and weight, with more specific details yet to be unveiled, according to Bao Weimin, a space expert at the China Aerospace Science and Technology Corporation. They will mainly be used for scientific experiments in such fields as biology, materials and basic physics.

The space station will operate in the low-Earth orbit at an altitude about 400 km to 450 km above the Earth surface. It has a designed life of 10 years, but experts believe it could operate more than 15 years if with appropriate maintenance and repairs.

Construction plan: 11 launches during 2021-2022

As one of China's most complicated space missions so far, the space station features a construction project that requires 11 launches in 2021-2022, including Thursday's successful launch of the core module, two more module launches, four manned missions and four cargo vessel flights.

Three types of Long March carrier rockets will jointly conduct the remaining 10 launch missions.

The Long March-5B rocket will be tasked with transporting sometime next year the two lab modules. The Long March-7 rocket will launch the cargo spacecraft and the Long March-2F rocket will launch the manned spacecraft into space. Two Tianzhou cargo vessels and Shenzhou manned spaceships will be launched later this year, and two more of each kind are planned next year.

China's three-step manned space program

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

The first step was to send astronauts into space and return safely. The launches of Shenzhou-5 manned spaceflight in 2003 and Shenzhou-6 manned spaceflight in 2005 fulfilled the mission.

The second step was to test key technologies needed for a permanent space station, including extra-vehicular activity, orbital docking, and in-orbit propellant refueling.

This phase included the launch of Tiangong-1, a transitional platform to test the docking technology, and the Tiangong-2 space lab.

China has launched 11 manned spacecraft, one cargo spacecraft, Tiangong-1 and Tiangong-2, sending 11 astronauts into space and completing the first two steps of the manned space program.

The third step is to assemble and operate a permanently crewed space station, which will mark a new high in China's space technology.

Bai Linhou, deputy chief designer of the space station at the China Academy of Space Technology (CAST), said the station could support at most six astronauts at the same time. Regular launches of crewed and cargo spaceships will secure a long-term manned presence to carry out in-orbit research and services.

Flight engineers and payload experts are among the astronaut reserve for the first time to meet the space station's maintenance and advanced research needs.

Such a large facility will provide many opportunities for scientific research and technological experiments, said Zhou. "It is bound to enrich our understanding of the universe and promote the development in science, technology and applications."

Seed breeding, pharmaceutical research, and development of critical materials in the space station are expected to produce economic benefits. The life support technology and energy technology are also likely to benefit economic and social development.

(With input from Xinhua)