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No reports yet of debris from falling satelliteBy
Published : Oct. 23, 2011 - 14:04
BERLIN (AP) _ Scientists were trying to establish how and where a defunct German research satellite returned to the Earth Sunday, after warning that some parts might survive re-entry and crash at up to 280 mph (450 kph).
There was no immediate solid evidence to determine above which continent or country the ROSAT scientific research satellite entered the atmosphere, said Andreas Schuetz, spokesman for the German Aerospace Center.
Most parts of the minivan-sized satellite were expected to burn up, but up to 30 fragments weighing a total of 1.87 tons (1.7 metric tons) could crash.
Scientists were no longer able to communicate with the dead satellite and it must have traveled about 12,500 miles (20,000 kilometers) in the final 30 minutes before entering the atmosphere, Schuetz said.
Experts were waiting for ``observations from around the world,'' he added.
Scientists said hours before the re-entry into the atmosphere that the satellite was not expected to hit over Europe, Africa or Australia. According to a precalculated path it could have been above Asia, possibly China, at the time of its re-entry, but Schuetz said he could not confirm that.
The 2.69-ton (2.4 metric ton) scientific ROSAT satellite was launched in 1990 and retired in 1999 after being used for research on black holes and neutron stars and performing the first all-sky survey of X-ray sources with an imaging telescope.
The largest single fragment of ROSAT that could hit into the earth is the telescope's heat-resistant mirror.
During its mission, the satellite orbited about 370 miles (600 kilometers) above the Earth's surface, but since its decommissioning it has lost altitude, circling at a distance of only 205 miles (330 kilometers) above ground in June for example, the agency said.
Even in the last days, the satellite still circled the planet every 90 minutes, making it hard to predict where on Earth it would eventually come down.
A dead NASA satellite fell into the southern Pacific Ocean last month, causing no damage, despite fears it would hit a populated area and cause damage or kill people.
Experts believe about two dozen metal pieces from the bus-sized satellite fell over a 500-mile (800 kilometer) span.
The German space agency puts the odds of somebody somewhere on Earth being hurt by its satellite at one in 2,000 _ a slightly higher level of risk than was calculated for the NASA satellite. But any one individual's odds of being struck are one in 14 trillion, given there are 7 billion people on the planet.
2톤의 獨위성 잔해, 450km 속도로 떨어진다
사용 연한이 지난 독일 관측위성의 잔해가 23일 오전 대기권에 진입, 지구로 떨어졌다고 뉴스통신 AP 등 외신들이 독일항공센터(DLR) 발표를 인용해 보도했다.
독일항공우주센터는 그리니치표준시(GMT)로 이날 오전 1시45분~2시15분(한국시 각 오전 10시45분~11시15분)에 관측위성 '로샛(ROSAT)'이 대기권에 진입했으나 잔해 가 지구 표면에 떨어졌는지, 떨어졌다면 어디에 떨어졌는지는 확인되지 않고 있다고 발표했다.
이에 앞서 일본 문부과학성은 로샛이 지구를 향해 낙하하면서 23일 오전 9시30 분께 일본 상공을 처음 통과한다고 전망했었다.
독일항공우주센터도 위성 잔해가 유럽과 아프리카, 오세아니아에 떨어지지는 않을 것이라고 말해 아시아에 추락할 가능성을 시사했다.
이와 관련, 일본 정부는 일본 영토에 로샛의 잔해가 떨어졌다는 보고는 아직 들어오지 않고 있으며 미국 국방부가 이 위성의 대기권 통과 지점을 인도양 상공으로 추정했다고 전했다.
추락하는 위성은 대기권을 통과하면서 대부분 타버리지만, 파편 30개 정도는 타 지 않은 채 추락할 가능성이 있다고 독일항공우주센터는 설명했다.
독일항공우주센터는 "가장 큰 잔해는 내열성이 강해 잘 타지 않는 망원경 거울 일 것"이라며 "무게가 최대 1.87t에 이를 수도 있다"고 언급했다.
한편, 독일과 일본 당국은 파편이 대부분 바다에 떨어질 것이라면서 지상에서 사람이 파편에 맞을 가능성은 매우 낮다고 강조했다.
그러나 전문가들은 파편 일부가 시속 450km의 속도로 지상에 추락할 수 있다고 경고했다고 외신들이 전했다.
Yoon touts improved Japan ties on Independence Movement Day
Bill to probe first lady fails to pass
Address by President Yoon Suk Yeol on the 105th March 1st Independence Movement Day