Good point! I just found the Nasa has published on this topic: http://www.nasa.gov/pdf/585584main_UARS_Status.pdf http://www.nasa.gov/pdf/585584main_UARS_Status

Good point! I just found the Nasa has published on this topic: http://www.nasa.gov/pdf/585584main_UARS_Status.pdf http://www.nasa.gov/pdf/585584main_UARS_Status.pdf Risk expected is one in 10000, but for every object if I understand it well. And the current one is rather 1/3200, probably because of its size.