Most of the craft should burn up on re-entry, so scientists said falling debris poses only a slight risk to people on the ground. "According to my knowledge, we have not found any harm to the Earth's surface".
The 40-foot long Tiangong-1, or "Heavenly Palace", is one of China's highest profile space projects.
Using radar and optical sensors, the 19,000 lb craft was tracked as it re-entered the atmosphere and largely incinerated everything aboard, with any remaining pieces coming to rest 2,400 miles Southeast of New Zealand - roughly the area that the International Space Station will be guided to fall into should that need arise in the next 10 years. But, the remote location likely deprived stargazers of a spectacle of fireballs falling from the sky.
Dr Jonathan McDowell, an astronomer at the Harvard-Smithsonian Centre for Astrophysics, said the module zoomed over Pyongyang in North Korea and the Japanese city of Kyoto during daylight hours, reducing the odds of glimpsing it before it hit the Pacific.
"Although Tiangong-1 was only a transitional platform between the spaceship and space station, it's a key step for China to acquire the spacecraft docking technology, and it demonstrated the possibility of long-time space residence for the Chinese", said Bai Ruixue, a former space journalist and now CEO of a company focusing on public understanding of space science. The Chinese space agency said it should happen during the course of today Beijing time. For 6 years of the mission the unit was visited by two teams of taikonaut from China. "It had helped us accumulate precious experience in constructing space station", said Huang Weifen, Deputy Chief Designer of the Astronaut Center of China.
The ability of Tiangong-1 space lab module to support the work and life of astronauts, the environment control, operation and performance of the docked spacecraft and lab module were tested. Space enthusiasts have been bracing for its return ever since.
Tiangong-1 was about as big as a school bus, weight approximately 9.4 tonnes, and most of it has probably burned on its way down.
Asked about the space station, Chinese foreign ministry spokesman Geng Shuang told a regular briefing he had no other information and reiterated that China had been reporting the situation to the United Nations space agency in an open and transparent way. An expert interviewed by nationalist tabloid Global Times said it "re-entered the atmosphere because it ran out of fuel, not because it's out of control". Reports to the contrary, it said Monday, were because "foreign media envy China's space programme". The station was an important part of China's bid to become a leading power in space.