You know what they say about things that go up, especially things made of metal that weigh 18,753 pounds.
Don’t start building a doomsday shelter yet. The Chinese space station Tiangong-1, which went rogue in space after it de-orbited and lost control last year, will be hurtling toward Earth soon (as in March), but most of it will self-immolate before any space junk has a chance of crashing into someone’s head. As Dr. William Ailor, principal engineer for the Center for Orbital and Reentry Debris Studies at Aerospace, told NBC Mach, you have a better chance of getting hit by lightning. Or winning the Powerball jackpot.
The question is where the debris should go so that 1 in several trillion chance becomes zero.
If any debris survives reentry—and a few random scraps could—it will crash to the surface. This could only happen in a hundred-something-kilometer region that Tiangong-1 actually passes over. The regions of highest probability are so narrow that the chance of a piece of the runaway space station falling there and finding an unlikely human target are almost nonexistent, and almost half the planet has no probability of being hit at all. More than half of Earth that falls within the low probability range is water.
Whether China can still control this thing is unknown. Its update to the U.N. last May went through the initial launch, structural integrity, orbit and orbital decay as well as a prediction of how the spacecraft will finally meet its end and how the process will be monitored, but there has been no word since.
“China attaches great importance to the re-entry of Tiangong-1 and will take the following measures in terms of monitoring and public information,” the report said. “First, it will further enhance monitoring and forecasting. China will make strict arrangements to track and closely monitor Tiangong-1 in its orbital development and will publish a timely forecast of its re-entry…. Second, it will improve the information reporting mechanism. Dynamic orbital status and other information relating to Tiangong-1 will be posted on the website of the China Manned Space Agency.”
There was also an early warning promised, but the question is exactly how early.
No amount of obsessive predicting can actually tell us where the final resting place of (what remains of) Tiangong-1 will be. As the spacecraft zooms along at 16,000 mph about 180 miles above Earth, it is constantly being stalked by ground stations, but it will be harder and harder to follow as gravity pulls it further in from orbit. The reality is going to sound scary: We really won’t know exactly where any of the disembodied remnants of this space corpse will land until the day before it actually falls.
Not to mention that “once it starts to break apart, each of the pieces will fall along the track, but they can be spread out by several hundred miles,” Ailor said. He believes that the reentry will probably be uncontrolled.
This still doesn’t mean we’re doomed. You will probably end up heading outside on that day without so much as an umbrella, but if you do happen to see the spacecraft's death throes manifesting as bright lights streaking the sky, Instagram it.
(via NBC Mach)