The Upper Atmosphere Research Satellite (UARS) was an orbital observatory launched in September 1991 from the Space Shuttle Discovery with the aim of studying the Earth’s atmosphere and in particular the ozone layer through ten different instruments performing chemical, dynamic and energy studies. This satellite allowed for example to study a number of chemicals present in the upper atmosphere and provided very valuable data concerning the amount of light coming from the Sun in the visible spectrum but also ultraviolet light.

The UARS orbital observatory mission was supposed to last three years but in 2005, when its end was declared for good, six of its instruments were still working. At that point the satellite was led into a low orbit that caused it to slowly sink lower and lower until between Friday September 23, 2011 and the next day it crashed disintegrating but exactly where did it crash?

We have grown accustomed to military systems that can identify any object in the sky but we can’t say exactly where the UARS pieces crashed. It’s true that this satellite was the size of a bus but during its re-entry into Earth’s atmosphere the extremely high temperatures caused by friction have torn it to pieces. Most of these pieces were so small that they were pulverized but some may have been large enough to reach the surface. This could’ve been a possible danger, since even a small object thrown at very high speed can cause serious damage and kill someone.

Initially it seemed that the UARS might fall on Central Europe but this satellite fell down completely uncontrolled, which means that its trajectory changed throughout the hours. The result is that according to NASA the fragments fell into the Pacific Ocean. In this case it may be impossible to determine with precision the impact area because it means that even the largest fragments sank to the bottom of the ocean.

Much has been said about the UARS fall but this was only one of thousands of more or less large pieces of debris in orbit. Filling the planet with trash wasn’t enough so over the years a lot was left in orbit too. We’re aware of it when one of those objects crashes but for the International Space Station, for any spaceship that travels in orbit and also for the satellites it’s problem. There are some projects to try to solve this problem but an adequate budget is needed. For now, NASA tries to keep track of space debris making satellites that are no longer used fall down. We hope that a project isn’t approved only after some tragedy.