aboard a  Long March 2F/G  rocket [1]  on 29 September 2011, [9]  it is part of the  Tiangong  program, which aims to place a larger, modular  station into orbit by 2020. [8]  Tiangong-1 will be deorbited in 2013, [10]  and replaced over the following decade by the larger  Tiangong-2 and  Tiangong-3