Three Chinese astronauts have begun a six-month mission, to work on the country's new space station.
It is China's latest step towards making itself a leading space power for the decades ahead.
What is the Tiangong space station?
Last year, China put into orbit the first module of its Tiangong or "Heavenly Palace" space station. It plans to add more modules, such as Mengtian science lab, by the end of the year.
Next year, it will launch a space telescope, called Xuntian. This will fly close to the space station, and dock with it for servicing and refuelling.
Tiangong will have its own power, propulsion, life support systems and living quarters.
