China started the selection process of the fourth batch of astronauts to join later manned space missions, according to the China Manned Space Agency (CMSA).

Between 12 and 14 candidates will be chosen, including seven or eight pilots. Engineers will also be selected as well as two payload experts.

The pilots will be selected among active pilots of China's armed forces. The engineers will be picked from researchers and technicians in aerospace or related industries. And the payload experts will be drafted among those also researching space science.

The posts of payload experts are also open to applicants from Hong Kong and Macao special administrative regions for the first time.

The CMSA will carry out the selection procedure which is expected to last about 18 months.

Currently the Astronaut Center of China is training the third batch of 18 astronauts before they are certified for space missions.

China has 21 astronauts in total from the first and the second generations. 14 of them have taken part in nine missions, including the latest Shenzhou-14 mission.