An eight-tonne space satellite launched by the Chinese in 2011 will drop out of orbit and hit Earth within the next few months, according to various media reports.
The satellite, named Tiangong-1, or “Heavenly Palace” in Chinese, is 12 meters long and 3.3 meters wide. It was used by the country’s space program to test spacecraft docking and was designed to test technology for a prospective space station. The lab malfunctioned in March 2016 and stopped working. As a result, China does not have control over its trajectory.
The government revealed in May 2017 that the satellite would likely return to Earth between October 2017 and April 2018. It was still orbiting about 300 kilometers above Earth on Oct. 19, so some time will pass before it crashes down on the planet. The good news is that most of the lab will burn up in the atmosphere, so the risk of injury to aircraft and people or objects on Earth will be “very low.”
Astronomer Jonathan McDowell from the Harvard-Smithsonian Centre for Astrophysics noted on Oct. 13: “Now that [its] perigee is below 300km and it is in a denser atmosphere, the rate of decay is getting higher. I expect it will come down a few months from now – late 2017 or early 2018.”
He added that sections of the satellite weighing up to 100 kilograms could still hit Earth’s surface.
McDowell pointed out that in 2012 and 2015 similarly-sized objects fell from Earth’s orbit. Of more concern was NASA’s Skylab space station, which was 10 times as heavy when it crashed in 1979. There was also Russia’s space station, which exited orbit in 2001 at a weight of 130 tonnes.
China has been keeping an eye on the space lab and has promised to alert the United Nations Office for Outer Space Affairs and the secretary general of the United Nations when the satellite gets close to re-entry.