Most of the space lab incinerated in Earth’s atmosphere on re-entry. And a small amount of space debris fell into a designated area in the South Pacific. Tiangong-2 has been in orbit for more than a 1,000 days – far longer than its planned two-year lifespan – after launching from the Jiuquan Satellite Launch Centre in September, 2016.
During that time it has accommodated two astronauts for 30 days, and conducted several cutting-edge science experiments.
Zhu Zongpeng, chief space lab designer at the China Academy of Space Technology, Tiangong-2 was in good condition and could have continued to orbit for several more years.
However, the decision was taken to de-orbit the space lab “responsibly”, before it got too old.
Zhu told reporters: ”Tiangong-2’s voluntary retirement is meant to eliminate all risks.
“Otherwise, the in-orbit reliability of the space lab will decline as the extended service stretches further longer than it was originally intended.
“Once some anomalies occur, Tiangong-2 would uncontrollably fall back to the atmosphere, and some parts might not be completely burned, with its debris falling to the ground, posing a threat to people.”
Tiangong-2 used a two-step strategy for its controlled de-orbit, ensure the descent took place at a designated time and location.
First, the space lab was lowered to an elliptical orbit of 200km.
And it then descended it to an elliptical orbit of 43 miles (70km) prior to its fiery re-entry through the atmosphere.
The planned de-orbit of Tiangong-2 comes after its predecessor, Tiangong-1, lost power in April 2018 and made an uncontrolled crash landing.
Tiangong-1 was initially supposed to be taken out of service in 2013, but its mission was repeatedly extended until China lost communication with the spacecraft.
Fortunately debris from the doomed spacecraft, which was travelling at 17,000mph, fell into the ocean, avoiding any casualties.
China is now preparing to launch its third temporary orbital lab, Tiangong-3, which will used to test key technologies.
The country’s ultimate aim is to launch a “real” space station in 2020, which will allow China will play a bigger role in satellite space exploration, manned space flight and space control.