A Chinese space station named Tiangong-1 is going to be falling back to Earth in a couple of months time. It is predicted that the Chinese space station will be falling sometime in late March and some big pieces might survive re-entry into the atmosphere. This has raised a lot of concerns about the safety and protection from falling debris.
Satellites fall to Earth from time to time. They get bombarded by small particles in the upper atmosphere and are eventually dragged down but they are usually small enough that they burn up completely on re-entering the atmosphere.
When it comes to Tiangong-1, the problem lies in its massive size. It was initially launched in 2011 served as the first crewed space station for China. The module is dense and weighs close to 19,000 pounds. It is estimated that upon re-entry, 10 to 40 % of a spacecraft makes it to the ground. For small satellites, that’s negligible but for Tiangong-1, it means somewhere between 2,000 to 8,000 pounds.