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Prior to the reboost of Tiangong 1 on 30 August 2012 , it was projected that a launch window would open between late November and December 2012 , when Tiangong-1 's orbit had decayed to the level of a Shenzhou 's standard orbit .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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