Space lab believed to be out of control

China appears to admit uncertainty about its re-entry

Tiangong 1, China’s first space laboratory, will come to a fiery end in late 2017. The average decommissioned satellite either burns up over a specific ocean region or is ejected to a far-off orbital graveyard. But Tiangong 1’s demise is shaping up to be something different.

Chinese officials appeared to admit that they had lost control of the station during a Sept. 14 news conference in Jiuquan.

“Based on our calculation and analysis, most parts of the space lab will burn up during falling,” Wu Ping, a director at China’s space engineering office, said during the conference. A day later, China launched Tiangong 2, the lab’s successor.

Wu added that China is monitoring the space station for collisions with other objects. And Xinhua, China’s government-run news agency, reported that the Chinese space agency may need to release an international forecast for where Tiangong will land at a later date — an uncertainty that seems to indicate the descent is uncontrolled.

For the moment, Tiangong 1 remains whole, currently orbiting the planet more than 200 miles above Earth’s surface. China launched Tiangong 1, which translates to “Heavenly Palace,” in 2011. It served as China’s base of space experiments for roughly 4 years. The last crewed missionwas in 2013, though the station continued to autonomously operate until it was decommissioned in March 2016.

Soon after, rumors surfaced that China no longer had control of the spacecraft. In June, amateur satellite tracker Thomas Dorman, from El Paso, Texas, warned Space.com that, based on his observations, the 8-ton space lab was out of control.

“If I am right,” Dorman said at the time, “China will wait until the last minute to let theworld know.”

Harvard University astrophysicistJonathanMcDowell agreed that China’s announcement indicated the spacecraft will fall where itmay.

“You really can’t steer these things,” McDowell told The Guardian.

Most satellites are not laid to rest this way. Many smaller craft incinerate completely in the upper atmosphere. For larger spacecraft destined for reentry, the usual method is a planned descent. The wreckage that survives reentry splashes down far fromhuman habitation.

Though much of Tiangong 1will disintegrate, McDowell predicted that 200pound pieces— the tougher remnants of, say, rocket engines— could withstand the trauma of re-entry.

Even though China may not be able to steer Tiangong 1’s flaming corpse into a specific spot, humans will likely be unharmed. The odds are very low it will fall in an inhabited area: Roughly speaking, half of the world’s population lives on just 10 percent of the land, which translates to only 2.9 percent of Earth’s surface.