CNN —Three astronauts lifted off to China’s nearly completed space station on Tuesday, marking the beginning of the country’s long-term presence in space. The Shenzhou-15 spacecraft is expected to dock with the Tiangong Space Station about 6.5 hours after launch. VCG/Getty ImagesSmaller than the ISSOnce construction is completed, the space station is expected to last for 15 years. Tiangong, which means heavenly palace, is smaller than the International Space Station but similar in its modular design. The new space station will typically house three rather than six astronauts.

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