Concerned eyes have been looking to the sky this week due to the expected uncontrolled reentry of the body of a Chinese Chang Zheng (Long March) 5B rocket. A large chunk of the spacecraft is tumbling around Earth in an out-of-control orbit and it's slowly getting closer to the surface. The latest analysis suggests that should end its trip and potentially land at some point this weekend.
Various space agencies, governments, and non-profits have been tracking the core booster stage since it was realized it was in an uncontrolled orbit on May 4. It's currently traveling at 29,000 kilometers (18,000 miles) per hour. It's unlikely it will hit land, and will most likely either burn up on reentry or land in the sea, but China has precedent for parts of a rocket landing in inhabited areas due to uncontrolled reentry before.
The current predictions for when it will reenter still have massive uncertainty. The Aerospace Corporation has narrowed reentry down to around 11:43 pm ET (3:43 am UTC) on Saturday, May 8, give or take around 16 hours. This will be refined over the next few hours as many are tracking the rocket, including amateur astronomers.
The Long March rocket was used to successfully launch the first module of China's planned Tiangong space station on April 29. The core made it to orbit successfully and unexpectedly so did this rocket. Instead of coming back to the ground after launch, the rocket was powerful enough to enter in a low orbit around the planet.
Friction with the atmosphere is slowing and lowering the rocket, which is 30 meters (99 feet) in length. In May last year, another Long March 5B rocket fell to Earth and some large chunks of metal damaged a village on Cote d'Ivoire. Luckily no one was hurt, but this second uncontrolled reentry of a Chinese rocket has people concerned for China's plans for future large rockets delivering the rest of the planned space station.
