It won’t be long now. China’s first space station, Tiangong 1, a two-bedroom, fixer-upper, will burn up in the Earth’s atmosphere sometime between March 28 and April 10.
The fixer-upper description refers to the fact that the Chinese lost contact with the craft in March 2016, so the original plan to de-orbit the spacecraft over an unpopulated area using on board thrusters won’t happen. Tiangong 1 is on its own and could burn up anywhere along its orbit which overflies a large swath of Earth between the latitudes of 43 N and 43 S. That includes much of the U.S., southern Europe, South America, Africa, India, Australia, New Zealand and much of Asia.
Weighing 9.4 U.S. tons, Tiangong 1, Chinese for Heavenly Palace S1, was launched on September 30, 2011. The station saw two manned missions by Chinese taikonauts (China’s name for an astronaut) including Liu Yang, China’s first female astronaut.
More than likely, most of the ship will burn up harmlessly in the atmosphere. But there’s a chance some of the heavier metal parts will survive and come crashing down. Narrow bands of latitude between about 39 and 43 north and south have a higher probability than other areas. For the U.S. that zone includes Pennsylvania, Ohio, Iowa, Nebraska, Wyoming, Nevada and northern California, among other states. On the very off chance a piece falls in your backyard, be wary. Don’t handle it as it could still be contaminated with hydrazine, a propellant used by space vehicles that’s toxic.
Why is Tiangong 1 falling in the first place? Unless a satellite or space probe orbits at a great distance from Earth like the geosynchronous satellites that beam TV from around the world to our homes, even the little bit of atmosphere several hundred miles up produces drag on a spacecraft. The same way a strong wind in your face will slow your running, atmospheric resistance slows the spacecraft and causes it to lose altitude. The lower it drops, the thicker the air, the greater the resistance and the faster its orbit decays. When it reaches about 62 miles (100 km), air resistance is strong enough to break apart and burn up a satellite.
NASA’s Skylab, which weighed 77 tons, re-entered on July 11, 1979; parts of the craft survived the plunge and landed in southwestern Australia. Next time you’re in Australia, take a side trip to the Esperance Municipal Museum in Esperance which boasts the “world’s most comprehensive display of NASA Skylab memorabilia.”
The largest man-made object to fall was Russia’s Mir space station. All 143 tons of it burned up on March 23, 2001. This was a controlled, rocket-fired re-entry, so the burn-up was targeted with the whole works breaking up over the South Pacific Ocean. No fragments were recovered.
If you’d like to get in some last looks at Tiangong 1 before it hits the drink, go to Heavens Above and either login or select your location from the map on the right side of the page. Then, return to the opening page and click the Tiangong 1 link in the left column. This will take you to a list of passes it will make for your city. If you see nothing listed for the period, click on the right-pointing arrow for the next set of passes. Click again if necessary until you see a list of times. Next, click on the date and a map will pop up showing the station’s path (along with times for each minute along the path).
Good luck! I’ll update with a rough estimate of where and when it might land as soon as I hear about it.
UPDATE: I see in a report from the UK’s Daily Mail that Tiangong 1 is expected to come down over Lower Michigan. There’s no source for this claim, and it’s not possible this far in advance to predict the fall zone with that kind of precision. We’ll only know much closer to re-entry — perhaps a day — approximately where it will come down.