BEIJING - China's planned space station will offer scientists from around the world opportunities for research and experimentation, the lead designer of China's manned space program told Xinhua on Friday.

Zhou Jianping said the space station, which is expected to be built by 2020 and is aimed at engaging in space exploration and research on space resources, will include three capsules. It will be capable of docking one freight spacecraft and two manned spacecraft, and the entire system will weigh over 90 tonnes.

The space station has been designed to accommodate three Chinese astronauts who will work in half-year shifts during its operation period, but new capsules can be added as needed for scientific research, Zhou said.

"In light of the current demand and cost factors, we are not going to ?build an international space station, but one of moderate size that meets the demands of scientific experimentation and technological testing, and its flexibility in adding capsules will enable us to adapt to the demands of the most state-of-the-art technological research," Zhou said.