NANJING - China's spacecraft tracking ship Yuanwang-5 is sailing to the Indian Ocean from a port in eastern China's Jiangsu province Sunday for a maritime space monitoring mission.

Yuanwang tracking ships have completed four missions since January, with more than 140 days at sea, a record high in recent years. They are expected to carry out more missions this year, according to the China satellite maritime tracking and controlling authorities.

China currently has four Yuanwang tracking ships. Four days ago, Yuanwang-7 sailed to the Pacific Ocean. Yuanwang-3 returned to port after finishing its latest monitoring mission for BeiDou-3 satellites, and Yuanwang-6 began its first overhaul at the end of April.

In 2019, the country will have more than 30 space launches, and the Yuanwang fleet will operate for more than 700 days at sea.

The mission members have made action plans and conducted rehearsals, preparing for future missions.