October 23, 2011
ROSAT Fell To Earth Late Saturday Night
The German-built RÃ¶ntgensatellit (ROSAT) fell back to Earth Saturday evening, officials from the National Aeronautics and Space Administration (NASA) told ABC News.
In a statement posted to their official website, the German Aerospace Center (DLR) said, "On Sunday, 23 October 2011, between 1:45 UTC (3:45 CEST) and 2:15 UTC (4:15 CEST) the German Roentgen Satellite ROSAT has re-entered Earth's atmosphere. There is currently no confirmation if pieces of debris have reached Earth's surface."
That would place the satellite's arrival time between 9:45 and 10:15 p.m. Eastern time on October 22.
An early morning Sunday report by the Associated Press (AP) said that scientists were attempting to determine how and where the inactive space telescope might have landed.
According to their reports, there was "no immediate solid evidence to determine above which continent or country" ROSAT would have re-entered the atmosphere, based on information provided to them by DLR spokesman Andreas Schuetz.
Previously, CNN.com's Michael Martinez reported that the as many as 30 individual pieces of debris weighing a combined 1.7 tons could survive re-entry into the planet's atmosphere. The AP noted that those surviving components could be travelling at speeds to 280mph.
According to Martinez, the DLR released a statement Saturday, warning that the largest fragment of the telescope that could survive will be the heat-resistant mirror. Earlier reports suggested that the largest single pieces of debris could weigh more than 800 pounds.
"ROSAT will likely end up in the sea," Gina Sunseri and Alyssa Newcomb of ABC News said Saturday, prior to receiving confirmation of the re-entry. Still, it's too soon to tell where it will crash. It's something that the U.S. space agency and the German space agency, who are monitoring ROSAT's re-entry, won't be able to tell until hours before re-entry."
"The German Space Agency is putting the chances at one in 2,000 that someone will be struck by a piece of ROSAT," they added. "That works out to odds of about one in 14 trillion that any one of the 7 billion or so people on Earth will be whacked by a piece of the satellite."
Martinez had reported that DLR officials believed the re-entry would occur between 2pm Eastern time Saturday and 7am Eastern time Sunday, and that fragments were expected to fall in a roughly 50-mile path somewhere in the path of ROSAT's orbit (an area covering 53 degrees northern and southern latitude).
Telegraph Science Correspondent Richard Gray pointed out that the inability to pinpoint the exact date, time, and location of ROSAT's re-entry is "due to fluctuations in solar activity, which causes the Earth's atmosphere to heat up and increases the amount of drag."
ROSAT's return to Earth came almost exactly one month after another defunct satellite, the NASA-built Upper Atmosphere Research Satellite (UARS), made it's re-entry into the planet's atmosphere and splashed down in the Pacific Ocean sometimes between 11:23 p.m. EDT on September 23 and 1:09 a.m. EDT on September 24.
As previously reported here on RedOrbit ROSAT was a 2.4 ton space telescope that became disabled after a guidance system failure in 1999. Previously, experts believed that the satellite would completely burn-up in the atmosphere, but that no longer appears to be the case.
ROSAT was a 5,300-pound satellite that was launched in 1990 and mapped approximately 110,000 stars, supernovas, and cosmic sources of X-rays during an 18-month span of activity. The satellite was named in honor of Wilhelm Roentgen, the Nobel Prize winning physicist who discovered X-rays. There was no propulsion system on board, making it impossible to control ROSAT's re-entry.
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