China is planning to launch its space station in 2018 and complete the project by 2022, Zhang Bonan, chief designer of China's manned spacecraft system, told China News Service on Wednesday.

The station will be multi-cabin with a large capacity and high power, where Chinese scientists and their international colleagues will be able to work together in labs, according to Zhang, who is also a deputy of the National People's Congress, China's top legislature.

The challenges that China needs to overcome are mainly supply lines, including the absorption of carbon dioxide and the collection and reuse of urine, to enable astronauts to live in space for a long time.

The scientist also said both China's Tiangong-1 space module launched in 2011 and the Tiangong-1 scheduled in 2016 serve to test the technology for life support systems.

China has conducted experiments with small-scale closed ecological systems on the ground to produce oxygen and absorb carbon dioxide by growing vegetables and using urine as fertilizer.

It is expected that astronauts can live off this ecological system, rather than on outside assistance, but the difficulty to maintain the balance is enormous, Zhang added.

But Zhang said that if humans want to move to other planets, an ecological system is a precondition.