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Significant development on the vehicles began in 2017 , with an initial prototype unveiled in September 2019 , while the new rocket engine ( Demo-2 ) development began in 2012 , with a first test flight performed in August 2019 .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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