The three taikonauts onboard China's Tiangong Space Station have successfully arrived back to Earth. Nie Haisheng, Liu Boming, and Tang Hongbo returned after spending three months inside Tiangong Space Station. The three taikonauts – a term modeled after the Chinese word for space 太空 (tàikōng) – completed the inaugural mission of the Chinese space station.

They launched on board the Shenzhou-12 spacecraft and landed back with it in the Gobi Desert at 05:34 UTC on September 17. The crew appears to be in good health and they will quarantine for 14 days to makes sure their immune system has not weakened too much in their sojourn in space. At 92 days, this was the longest crewed mission that China has ever conducted.

Tiangong is still a work-in-progress. Just like the International Space Station (ISS), Tiangong is modular, so it is being constructed in stages. Currently, it is composed of the main module Tianhe. Two experiment modules will be launched next year. The first, Wentian (meaning Quest for Heavens), is expected to launch around May-June 2022, followed about three months later by Mengtian (meaning Dreaming of Heavens). Once complete it will have about one-fifth of the mass of the ISS.

On top of the scientific modules, Tiangong will also be equipped with a telescope module, currently under construction, called Xuntian (whose literal meaning is Touring the Heavens).  The telescope is going to have a primary mirror 2 meters (6.6 feet) in diameter with a field of view 300 times larger than the Hubble Space Telescope. Over the 10-year primary mission, Xuntian is expected to image 40 percent of the sky with its 2.5 gigapixel camera.

Unlike the ISS, Tiangong won’t be continuously inhabited. The next crew going up will be the Shenzhou 13 in October for a duration of 6 months, and it will be followed by two more crews in 2022.

Counting the seven astronauts and cosmonauts in the ISS, the four civilian crew members on Inspiration4, and these three taikonauts, yesterday was the busiest day in space in the history of humanity. There have never been as many as 14 people in orbit around the Earth before.