ROSAT Almost Crashed Into Beijing

The german ROSAT space telescope (Credits: PD-USGov-NASA).

According to German newspaper Der Spiegel, the German Roentgen Satellite (ROSAT) almost crashed into Beijing during its reentry. “ROSAT nearly caused what would have been among the worst catastrophes in the history of space exploration,” reads the article, “In the night from Oct. 22 to 23 last year, the defunct satellite fell to Earth — just barely missing the Chinese capital Beijing, population 20 million.”

ROSAT was a 2.5 tons satellite built up with very durable materials. The heaviest component was the satellite’s X-ray optical system, whose mirrors and mechanical support was held in place by a massive structure made of carbon-fiber reinforced composite. A study published before reentry predicted that up to 1.6 tons of satellite fragments, more than half of the spacecraft’s mass, could have survived reentry. Is has been estimated that as many as 30 individual pieces could have made to the ground.

A hypothetical impact on Beijing would have surely caused deep craters, damage to buildings and human casualties.  According to calculation by the European Space Agency, what made the difference was a window of just a few minutes: “Our calculations showed that, if Rosat had crashed to the ground just seven to 10 minutes later, it would have hit Beijing,” says to Der Spiegel Heiner Klinkrad, head of the ESA’s Space Debris team, “[an impact was] very much within the realm of possibility.”

The ROSAT project was developed jointly by Germany, the United States, and the United Kingdom. The launch was procured by DLR , the Germany’s space agency. Launched on June 1, 1990 on top of a Delta II rocket, the spacecraft operated successfully for nearly nine years, until February 12, 1999. At the time of reentry, the spacecraft was completely inert spacecraft is completely inert, so there was no way to control its final trajectory. The satellite plunged into the waters of the Bay of Bengal on October 22, 2012, with no damages to people or property.

The video, below, shows a reconstruction of the reentry of ROSAT.


About the author

Andrea Gini

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Andrea Gini is a content strategy consultant specialized in companies of the space sector. He is founder of Space Safety Magazine, where he held the position of Editor-in-Chief until March 2015. Between 2011 and 2013 he worked in the European Space Agency in the Independent Safety Office, which overviews the utilization of the International Space Station. He previously worked as Software Developer, IT Consultant, and trainer of Java-related technologies. Andrea holds a BSc and an MSc in computer science from the University of Milano, a Master in Communication of Science from the International School for Advanced Studies of Trieste and a MSc in Space Studies from the International Space University.

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