Anxiety as Chinese space lab Tiangong-1 crashes back to Earth
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experts have downplayed any concerns about the tiangong-1 causing any damage when it hurtles back to earth with the esa noting that nearly 6000 uncontrolled re-entries of large objects have occurred over the past 60 years without harming anyone1 an out-of-control chinese space laboratory tiangong-1 that will plunge back to earth in the coming days is unlikely to cause any damage chinese authorities say but will offer instead a splendid show akin to a meteor shower1 the concern is expressed by the us-based aerospace corporation over possible exposure by humans to hydrazine the deadly chemicals used as rocket fuel. it is cancerous and may cause liver and nerve damage the agency said1 but there is no need for people to worry the china manned space engineering office cmseo said on its wechat social media account1 such falling spacecraft do not crash into the earth fiercely like in sci-fi movies but turn into a splendid meteor shower and move across the beautiful starry sky as they race towards the earth it said1 chinas space agency said on thursday that the nearly eight-tonne tiangong-1 will re-enter the atmosphere some time between saturday and monday. the european space agency has a smaller window between midday saturday and early sunday afternoon gmt time1 the lab was placed in orbit in september 2011 and had been slated for a controlled re-entry but it ceased functioning in march 2016 and space enthusiasts have been bracing for its fiery return1 beijing sees its multi-billion-dollar space programme as a symbol of the countrys rise. it plans to send a manned mission to the moon in the future1 china sent another lab into orbit the tiangong-2 in september 2016 and hopes to turn it into a crewed space station by 20221 the chinese assurances came amidst anxieties about where the 8618.255 kg craft will make its landing1 the cmseo said the probability of someone being hit by a meteorite of more than 200 grammes is one in 700 million1 during the uncontrolled re-entry atmospheric drag will rip away solar arrays antennas and other external components at an altitude of around 100 kilometres according to the chinese space office1 the intensifying heat and friction will cause the main structure to burn or blow up and it should disintegrate at an altitude of around 80 kilometres it said1 most fragments will dissipate in the air and a small amount of debris will fall relatively slowly before landing most likely in the ocean which covers more than 70 percent of the earths surface1 jonathan mcdowell an astronomer at the harvard-smithsonian center for astrophysics estimates that the tiangong-1 is the 50th most massive uncontrolled re-entry of an object since 19571 much bigger things have come down with no casualties mcdowell told afp1 this thing is like a small plane crash he said adding that the trail of debris will scatter pieces several hundred kilometres apart1 at an altitude of 60-70 kilometres debris will begin to turn into a series of fireballs which is when people on the ground will see a spectacular show he said1