Chinese astronauts has arrived at the Tiangong space station, where they completed the country's first-ever crew handover in orbit, state news agency Xinhua reported.
The trio blasted off aboard a Long March-2F rocket at 11:08 pm from the Jiuquan launch centre in northwestern China's Gobi desert, Xinhua said, citing the China Manned Space Administration (CMSA).
The vessel — carrying veteran Fei Junlong and first-time astronauts Deng Qingming and Zhang Lu — successfully docked with the station early on Wednesday, the agency said, according to Xinhua.
They then joined three other astronauts who had been aboard the Tiangong space station since early June.
Fei, 57, returns to space after 17 years, having commanded the Shenzhou-6 mission in 2005.
The mission's main responsibilities were "achieving the first crew handover in orbit, installing... equipment and facilities inside and outside the space station, and carrying out scientific experiments," said CMSA spokesman Ji Qiming.
"During the stay, the Shenzhou-15 crew will welcome the visiting Tianzhou-6 cargo ship and hand over (operations to) the Shenzhou-16 manned spaceship, and are planning to return to China's Dongfeng landing site in May next year."
The Tiangong space station is the crown jewel of Beijing's ambitious space programme — which has landed robotic rovers on Mars and the Moon and made the country the third to put humans in orbit — as it looks to catch up with the United States and Russia.
Tiangong's final module successfully docked with the core structure earlier this month, state media said — a key step in its completion by year's end.
"I expect that China will declare construction completion during or at the end of the Shenzhou-15 mission," independent Chinese space analyst Chen Lan said.
China has been excluded from the International Space Station since 2011, when the United States banned NASA from engaging with the country.
Once completed, the Tiangong space station is expected to have a mass of 90 tonnes — around a quarter of the ISS — or similar in size to the Soviet-built Mir station that orbited Earth from the 1980s until 2001.
Tiangong, which means "heavenly palace", will operate for around a decade and host a variety of experiments in near-zero gravity.
Next year, Beijing plans to launch the Xuntian space telescope with a field of view 350 times that of NASA's Hubble Space Telescope.