China's first prototype space station, named Tiangong-1 (Chinese for "Heavenly Palace 1"), is expected to reenter the Earth's atmosphere sometime between January and March 2018 following the end of its operational life, during which most of the craft should burn up. The reentry may take place over any spot on Earth between 43ºN and 43ºS. Due to the station’s mass and construction materials, there is a possibility that some portions of it will survive and reach the surface.
The European Space Agency (ESA) announced this week it will host a test campaign to follow the reentry of Tiangong-1, which will be conducted by the Inter Agency Space Debris Coordination Committee (IADC). IADC comprises space debris and other experts from 13 space agencies/organizations, including NASA, ESA, European national space agencies, JAXA, ISRO, KARI, Roscosmos and the China National Space Administration.
IADC members will use this event to conduct their annual reentry test campaign, during which participants will pool their predictions of the time window, as well as their respective tracking datasets obtained from radar and other sources. The aim is to cross-verify, cross-analyse and improve the prediction accuracy for all members.
ESA will act as host and administrator for the campaign, as it has done for the twenty previous IADC test campaigns since 1998. A special case for ESA was the campaign in 2013 during the uncontrolled reentry of ESA’s own GOCE satellite.
Tiangong-1 space station. Credit: ESA
Tiangong-1 was launched September 29, 2011, and served as both a manned laboratory and an experimental testbed to demonstrate orbital rendezvous and docking capabilities. On March 21, 2016, after more than 2 years of extended lifespan, China's officials announced that Tiangong-1 had officially ended its service.
The spacecraft is 12 m (40 feet) long with a diameter of 3.3 m (10.8 feet) and had a launch mass of 8 506 kg (18 700 lbs). It has been unoccupied since 2013 and there has been no contact with it since 2016.
The craft is now at about 300 km (186 miles) altitude in an orbit that will inevitably decay sometime between January and March 2018, when it will make an uncontrolled reentry.
"Owing to the geometry of the station’s orbit, we can already exclude the possibility that any fragments will fall over any spot further north than 43ºN or further south than 43ºS," says Holger Krag, Head of ESA’s Space Debris Office.
"This means that reentry may take place over any spot on Earth between these latitudes, which includes several European countries, for example."
"The date, time and geographic footprint of the reentry can only be predicted with large uncertainties. Even shortly before reentry, only a very large time and geographical window can be estimated."
Owing to the station’s mass and construction materials, there is a possibility that some portions of it will survive and reach the surface.
In the history of spaceflight, no casualties due to falling space debris have ever been confirmed.
ESA’s Space Debris Office, based at the European Space Operations Centre, Darmstadt, Germany, will concurrently conduct an international expert workshop in the week of February 28, focusing on reentry predictions and atmospheric break-up studies, enabling experts to share their latest findings and research in these and related topics.
Separate from the IADC campaign, ESA will regularly update ESA Member State civil authorities with detailed information on the reentry, as it does during all such events.
Featured image: Tiangong-1