Satellite crash app

摘要

ONLY a month after NASA's 6-tonne UARS satellite plummeted into the Pacific Ocean, another defunct satellite, the ROSAT X-ray telescope, is set to hit the Earth. At 2.4 tonnes ROSAT is much smaller than UARS, but more of it could survive re-entry, posing a risk to people. For ROSAT to undertake X-ray imaging of the heavens its cluster of optical mirrors had to be extremely heat resistant - and that means a 1.6-tonne chunk of it is unlikely to burn up. The satellite will crash-land some time between 21 and 24 October. As New Scientist went to press, increased solar activity in the upper atmosphere was slowing ROSAT at a rate that should see it come out of orbit at around 2030 GMT on 22October.