Source: Space.com
Source: Space.com
03/25/2018 – China’s first prototype space station, Tiangong-1, will come crashing back to Earth between March 30 and April 2 in an uncontrolled re-entry, give or take a few days, according to the latest forecast by the European Space Agency.
Tiangong-1, whose name translates as “Heavenly Palace-1,” launched without anyone aboard on Sept. 29, 2011. It settled into an orbit about 217 miles (350 kilometers) above Earth — a little lower than the International Space Station, whose average altitude is 250 miles (400 km)
Tiangong-1 was designed to keep ticking for just two years, and the Shenzhou-10 visit marked the end of the space lab’s operational life; China put it into “sleep mode” shortly thereafter. Originally, Chinese officials had said they planned to de-orbit Tiangong-1 in a controlled fashion, using the craft’s thrusters to guide it into Earth’s atmosphere. But in March 2016, China announced that Tiangong-1 had stopped sending data back to its handlers. The spacecraft’s functions “have been disabled,” according to a report at the time by the state-run Xinhua news service.
So a controlled re-entry was no longer in the cards; the space lab would fall back to Earth on its own, pulled down by atmospheric drag.
Tiangong-1 won’t be the biggest spacecraft ever to fall uncontrolled from the sky. In July 1979, for example, NASA’s 85-ton Skylab space station burned up over the Indian Ocean and Western Australia. Some big chunks survived the fall, and the Australian town of Esperance famously sued NASA $400 for littering. And in February 1991, the Soviet Union’s 22-ton Salyut 7 orbital outpost came tumbling down while it was connected to another 22-ton spacecraft called Cosmos 1686. Nobody was aboard Skylab or the Salyut-Cosmos 1686 complex when they hit Earth’s atmosphere. (The Soviet-Russian space station Mir was even larger, at about 140 tons. But its March 2001 destruction was a controlled re-entry.)
Based on Tiangong-1’s orbital details, that will happen somewhere between 43 degrees north latitude and 43 degrees south — a huge swath of the globe that stretches from the South Dakota-Nebraska border all the way down to Tasmania.
Most of Tiangong-1 will break apart and burn up in Earth’s atmosphere, but some of the space lab’s hardier pieces will probably survive re-entry, experts have said. However, these flaming space-junk chunks will probably splash down in the ocean, which covers about 70 percent of the planet’s surface.
And don’t worry about death from above: The chances that a piece of Tiangong-1 will hit you are less than 1 in 1 trillion, according to an FAQ published by The Aerospace Corporation.
But if you do stumble across a piece of smoking space wreckage, don’t pick it up or breathe in any fumes it may be emitting, the FAQ added: It might be made of, or carrying, toxic material.
And by the way: The law of finders-keepers doesn’t apply to space junk. “Any pieces of Tiangong-1 that reach the ground, regardless of where they fall, remain property of China until the Chinese government explicitly relinquishes ownership,” Robert Pearlman, editor in chief of the space history and memorabilia site (and Space.com partner) collectSPACE, told Space.com. Such ownership is spelled out in the 1967 Outer Space Treaty, which both China and the United States have signed, Pearlman explained.
A map showing the area between 42.8 degrees north and 42.8 degrees south latitudes (in green), over which Tiangong-1 could re-enter. The graph at left shows population density.
Credit: ESA CC BY-SA IGO 3.0
