Space Junk Will German Satellite Crash Into Earth?

Parts of Rosat, a massive, out-of-control German satellite, could smash into the earth sometime between October and December this year. Officials in Germany, however, say that humans likely are not in danger.

Rosat, a 2.4-ton German satellite, is out-of-control and headed for earth's atmosphere.

Rosat, a 2.4-ton German satellite, is out-of-control and headed for earth's atmosphere.

The German government is scrambling to determine how to deal with a rogue research satellite that a report states could crash into earth later this year. Up to half of the 2.4 ton, decommissioned Rosat research satellite could fail to burn up completely when it re-enters the planet's atmosphere sometime between October and December. SPIEGEL ONLINE has learned that the federal government has obtained an analysis indicating that the satellite is at risk of crashing down to earth during an 80-day window of time.

Because its final path is impossible to predict, no one knows for sure whether the X-ray research satellite, decommissioned in 1999, might hit a populated area. The satellite includes a considerable amount of ceramic and glass in its design that experts fear will be too heavy to burn up completely upon reentry into the earth's atmosphere.

A best-case scenario would see Rosat, now 370 Kilometers (about 230 miles) in the sky, incinerate in the atmosphere or land in the ocean. A worst-case scenario has about half the satellite reaching the earth, smashing into a major city at a speed of up to 400 kilometers (248.5 miles) per hour, and causing an untold amount of damage. Danger to Humans Unlikely

But the German Aerospace Center (DLR) is warning against any mass panic.

"It's very improbable that people would be hit," DLR chief Jan Wörner told SPIEGEL ONLINE. "A lottery win is more probable."

If history is a guide, Wörner's optimism is well-placed. Between 100 and 200 large objects, such as satellites, re-enter the earth's atmosphere each year, according to the Center for Orbital and Re-Entry Debris Studies at the Aerospace Corporation, which provides technical and advisory services to the US government's space programs.

Many simply burn up. And even the biggest objects rarely cause serious damage, although, like Rosat, they could if they hit a populated area.

The 69-ton Skylab, the United States' first space station, is perhaps the best-known example. In 1979, debris from the spacecraft hit Western Australia and part of the Indian Ocean, although no one was hurt.

To understand how Rosat became a problem satellite, one must also look at its history. The high-tech device, built by the German aerospace company Dornier, was supposed to be taken to space by a Space Shuttle and later captured again. But the Challenger Space Shuttle explosion in 1986 forced a change of plan.

In 1990, rockets finally lifted Rosat into space from Florida, where the scientific community declared it a phenomenal success. Around 125,000 previously unknown sources of X-ray radiation were discovered by the spacecraft during its nearly nine-year reconnaissance career. More than 700 scientists generated thousands of publications from the data.

Can Rosat Be Shot Down?

Rosat completed its mission but began experiencing technical problems. On Feb. 12, 1999, officials switched it off. Since then, it has continued to orbit the earth, but officials are unable to control or establish electronic contact with the satellite.

Officials in Germany have already begun discussing the possibility of shooting the satellite down if it becomes an acute danger to humans. But could it be brought down by a carefully targeted missile or knock the satellite out of orbit using laser pulses sent a regular intervals? There are reports that the US and China have used similar techniques in the past to snuff out rogue satellites.

But that outcome in Germany is unlikely. "We don't have the equipment for that," Warner says.


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