China has embarked on its first crewed space mission in almost five years, launching a trio of astronauts into orbit to occupy its under-construction space station. The crew will remain aboard the station's core module for a three-month mission carrying out testing and validation of vital onboard systems, before the two final modules are launched and operations commence over the next 18 months.

The Tiangong space station is to be the third orbiting laboratory launched and operated by China, following the Tiangong-2 station launched in 2016 and de-orbited in 2019, and Tiangong-1 station that launched in 2011 and ceased operation in 2016.

Tiangong, which means "Heavenly Palace," is a modular station just like the International Space Station, albeit a smaller one with capacity for three astronauts rather than six. The core capsule, called Tianhe, was launched back in April, is around the size of a bus and carries the station's life support systems, along with the living quarters for its crew.

The 22-ton Tianhe module was launched atop a Long March-2F carrier rocket from China's Gobi Desert on Thursday, with astronauts Nie Haisheng, Liu Boming and Tang Hongbo onboard. The Shenzhou-12 spacecraft that is carrying the astronauts will dock with the Tianhe module in orbit alongside the Tianzhou 2 cargo spacecraft that launched back in May.

After climbing aboard the Tianhe module, the astronauts will spend three months living and working there, outstripping the previous 33-day record for a Chinese crewed mission held by the astronauts of the Shenzhou-11 mission in 2016.

Among the tasks in store for the Shenzhou-12 crew will be carrying out in-orbit tests of the Tianhe module, verifying the recycling and life support systems, testing a robotic arm and managing materials and waste. They will also assemble and test extravehicular spacesuits and carry out two spacewalks, conduct science experiments and monitor their health as they go about their business.

Sometime in 2022, Tianhe will be joined by two smaller modules designed for scientific experiments, with the entire orbiting laboratory expected to be fully operational by the end of that year.

Sources: Xinhua, The Conversation