Recently, with the news of Tiangong-1 impacting Earth this week, there has been much concern about where it will land and whether it will hurt anyone. The truth is it probably won’t. Although most current space stations are designed to run controlled burns to land in the ocean, there are a few exceptions. Tiangong-1 (China’s first station, launched in 2011) lost communication with the ground a few years ago. Since it is tumbling in space with no one talking to it, we are at the mercy of probability about where it will land. Luckily humans take up a small percentage of surface area on the Earth; so realistically, no one is probably going to get hit.
Taingong 1 by CSMA
The truth is that this has happened before. The United State’s own first station, Skylab, came crashing down after losing communication with the US. Many pieces actually came burning down right over Australia, leaving some citizens with their own mementos from space right outside their backyards. The only person to actually get impacted by a piece of space debris wasn’t hit by a satellite at all. A good old meteorite, or rock from space, hit Ann Hodges in rural Alabama back in 1954. More likely the space station, if it hits land, will just cause property damage, like the hunk of steel did below.
a stainless steel satellite part in Texas by NASA APPEL
One of the reasons that the forecasts for where the station will land are so spotty is that the largest contributor to bringing a satellite down, atmospheric drag, is very unpredictable. The Earth’s atmospheres expands and contracts not only due to weather but also do to interactions with solar particles, so it is very hard to definitively say the exact second there will be enough drag to finally bring the station to Earth. But with every day closer to the estimated reentry, that window will start to narrow down.
In the meantime, you can see Tiangong-1 right now in the sky! Check out my post on how to find satellites here to see if you are one of the lucky ones to see the station before its demise. Heavens Above also has a live ground track for Tiangong 1 if you want to keep your eye on it.
Happy Observing!
