Picture a rocket stage the size of a ten-story building tumbling back through the atmosphere, and the best available answer to "where will it land" being a shrug and a map of most of the planet. That has happened more than once.
China's Long March 5B has, on several launches, left its roughly 20-tonne core stage to make an uncontrolled reentry rather than guiding it to a safe disposal. Debris has come down over West Africa and across various ocean and island regions. NASA publicly criticized the lack of control after more than one of these events.
- Object: Long March 5B core stage
- Mass: about 20+ tonnes
- Uncontrolled reentries: 2020, 2021, 2022
- Debris seen: West Africa (2020), ocean and island regions
- Response: public criticism from NASA
A planetary coin flip
An uncontrolled reentry of something this large is a gamble taken on everyone's behalf, and we keep taking it.
"It will probably land in the ocean" is true right up until the day it is not. The fix has two halves: design big rocket bodies for controlled disposal, and remove the dead mass already up there. The second half, capturing things that cannot bring themselves down, is the half Space Waste is building toward.
Most of Earth is water. Most is not a comforting margin when the object weighs twenty tonnes.
See the roadmap →Sources: Long March 5B · NASA