NANJING -- Yuanwang space tracking ships, which follows the progress of satellites and other space-bound craft, will carry out 19 maritime space monitoring missions in 2017, according to the maritime satellite measurement and control authority on Wednesday.

Yuanwang-5 left port Wednesday and Yuanwang-6 started its journey Monday.

Yuanwang-7 and the rocket transporting fleet will set sail in April.

In 2016, Yuanwang ships completed 14 major scientific research and experiment tasks, including maiden flights of the Long March-7 and the Long March-5, and space journeys of the Tiangong-2 space lab and the Shenzhou-11 manned spacecraft.