The German X-Ray Satellite ROSAT is forecast to re-enter the atmosphere (most likely) this Sunday Australian time (23 October 2011). At this stage, the uncertainty is possibly up to 72 hours either way of Sunday. I have my fingers crossed that I get to see it re-enter as it should produce an extremely bright fireball visible in daylight. It is not possible to predict what part of the world it will re-enter over, but it does pass over Australia regularly. Up to 1,600 kg of the satellite is expected to survive re-entry and whatever crashes to Earth will impact with a speed of around 450 k/m an hour. According to the German Space Agency, there is a 1 in 2,000 chance that someone will be hit by debris from the satellite. I will post updates via my Twitter account (Go to Twitter.com and search for Nightskyonline).
If you live in Australia, then you are out of luck in terms of seeing ROSAT pass overhead before it decays. There are a number of what is termed a ‘invisible’ pass which you could look out for. These might sound mysterious but they aren’t. It simply refers to passes that occur during in daytime or at night (as opposed to the twilight periods when it is dark on the Earth’s surface but still light up in space). I will be out looking tomorrow night (late Saturday night Australian time) in the hope that I may see the satellites plasma trail as it passes overhead. This is apparently left behind by a satellite once it is in the slightly denser layer of the Earth’s upper atmosphere. For information, on how to generate viewing information for your location for when to see ROSAT go here on this website.
