Fallen German Sattellite Could Prove More Dangerous Than UARS

Another dead satellite is set to enter Earth's orbit sometime soon; this time it's the German Roentgen Satellite (ROSAT).

The ROSAT X-ray astronomy observatory may be smaller in size and less massive in weight than NASA's Upper Atmospheric Research Satellite (UARS), but German space officials predict it will spread three times more debris and pose a greater threat to Earth's inhabitants.

Its orbit extends from the latitudes of 53-degrees North and South, which means it could reach from Canada to South America.

The ROSAT comes in at a total weight of 2.4-metric tons. It no longer has a propulsion system and there is no fuel left onboard.

When it finally enters Earth's atmosphere, it will come in at a speed of 17,000-mph.

The 3,000-degree Fahrenheit temperature will burn up much of the spacecraft as well.

Heiner Klinkrad, head of the European Space Agency's space debris office, had this to say: "All these forces exerted on the satellite cause it to disintegrate, which in turn means that it eventually lands in the form of a long debris trail. The lightweight objects fall to Earth first, similar to leaves from a tree. The really heavy objects land later, because they ultimately have to drill their way through the atmosphere."

German space officials have warned people that up to 1.7 metric tons of satellite debris, consisting primarily of up to 30 large glass and ceramic fragments, could reach Earth's surface.

In a statement to Space.com, the head of Germany's space agency Jan Woerner said, "We don't expect big parts to re-enter, except the mirror and the glass and ceramic parts. Usually during re-entry, you have rather clear burning of all the elements, but glass and ceramics may survive and may come down in bigger pieces."

There is a 1-in-2,000 chance that someone will be struck by fragments of ROSAT on its way down, according to Germany. That equates to odds of about 1-in-14 trillion that any individual person will be hit.

The dead satellite is currently being monitored by German aerospace officials, but no word yet on where and when it will fall roughly two hours before it hits Earth.

The predicted entry of ROSAT into Earth's atmosphere is between Oct. 20 and Oct. 25. It was originally expected to fall in November.

The threat from UARS isn't as high as ROSAT's. An analysis from NASA showed there was a 1-in-3,200 chance of a collision between a human and a piece of UARS.

NASA said they expected 1,200 pounds of UARS to survive re-entry. The remnants of UARS proceeded to fall in the remote Pacific Ocean.

Jan Woerner says Germany has studied NASA's response to UARS in preparation for ROSAT: "For us, it was an advantage that UARS fell before. We know now a little better how to interpret all the data and use the global network. It was an advantage that the satellite came down before so that now we can look at how to deal with ROSAT and how we deal with this in the future."