According to the China Manned Space Agency (CMSA), Shenzhou-12 manned spaceship successfully docked with the space station core module Tianhe on Thursday afternoon and entered the orbital capsule from the return capsule of the spaceship.
After a series of preparations, the astronauts opened the hatches of the node and the Tianhe module and entered the Tianhe module one by one, signifying that for the first time the Chinese have entered their own space station, the CMSA said.
The trio will carry out relevant work as planned, it said in a statement here.
The spaceship, launched on Thursday morning, completed orbital status setting after entering the orbit and conducted a fast autonomous rendezvous and docking with the front docking port of Tianhe, forming a three-module complex with the cargo craft Tianzhou-2, the state-run Xinhua news agency reported. The whole process took approximately 6.5 hours. This is Tianhe''s first rendezvous and docking with a Shenzhou spaceship since it was sent into orbit on April 29, the report said.
Earlier, the spaceship, atop a Long March-2F carrier rocket, was launched from the Jiuquan Satellite Launch Center in northwest China''s Gobi Desert.
In a textbook launch, telecast live by the official television channels, spacecraft Shenzhou-12 sent the three astronauts into the same orbit of the core module of the space station Tianhe launched in April.
Billed as the most prestigious and strategically important space project for China after the country''s recent Mars and previous Moon missions, the low orbit space station would be the country''s eye from the sky, providing round the clock bird''s-eye view for its astronauts on the rest of the world.
The space station will operate in low-Earth orbit at an altitude of 340-450 km above Earth''s surface for more than 10 years.
The astronauts, commander Nie Haisheng, 56, Liu Boming, 54 and Tang Hongbo, 45, will stay there for a three-month long mission to carry out the painstaking work of building the space station, which is expected to be ready by next year.
"It feels great," Nie, a veteran who took part in two previous manned space missions, said after reaching the near earth-orbit.
It will be China''s longest crewed space mission to date and the first in nearly five years.
China previously sent the space station''s Tianhe core cabin module on April 29, and a cargo spacecraft with supplies on May 29.
The three astronauts, who will build the station, are expected to set a new record for China''s manned space mission duration, exceeding the 33 days kept by the Shenzhou-11 crew in 2016.
The spacecraft was launched ahead of next month''s centenary celebrations of the ruling Communist Party of China (CPC) to showcase it as one of its important achievements of China under its leadership.
Considering its political significance, two vice-premiers with responsibility for science and technology, Han Zheng and Liu He, attended the launch event at the Beijing Aerospace Flight Control Centre, besides China''s top military Generals including Defence Minister Gen. Wei Fenghe.
Highlighting the space station''s significance, astronaut Nie in his media interaction on Wednesday made no secret that the mission is closely tied with China''s ambition to become a leading space power.
"This mission will be the first manned flight as part of the China space station''s construction," said Nie, who has been a Communist Party member for more than three decades.
"China''s space exploration development has crystallised the Chinese people''s thousand-year dream of flying to the sky, and added a heroic chapter to the 100-year history of struggle of the [Chinese Communist] party," he said.
Once ready, the station is expected to be opened for China''s close allies like Pakistan and for other international space cooperation partners.
The official media said that China''s purpose of space exploration has all along been the peaceful use of what many call the final frontier of humanity.
"Beijing has never intended to join a zero-sum space race or compete for global space leadership," Xinhua news agency said in a commentary.
"From the Moon to Mars, from unmanned planet roaming to manned space missions, China goes into the deep space with an open mind as well as steadfast readiness to cooperate with others and to share its achievements," it said.
China''s space station will be equipped with a robotic-arm over which the US has raised concerns for its possible military applications.
The arm, which can be stretched to 15 metres, will also play a vital role in building the space station in orbit, Zhou Jianping, chief designer of China''s manned space engineering project, had said.
Astronauts will team up with the robotic arm to make in-orbit space station construction and maintenance possible.
China, in the past, has launched several scavenger satellites fitted with robotic arms to gather and steer space debris so that it burns up in Earth''s atmosphere.
China plans to send several space missions including with astronauts to carry supplies and materials to complete the construction of the space station.
Thursday''s launch is China''s seventh crewed mission to space and the first during the construction of China''s space station.
While Beijing showcased the space station as a success, there were also concerns about the debris as China is set to launch several space missions during the construction of the station.
Last month, the debris of Long March-5B Y2 which had launched the core module caused a global stir as it fell back to Earth. Its remnants safely crashed into the Indian Ocean near the Maldives on May 9 with no reports of damage.
The hurtling debris of the rocket evoked sharp criticism from the US, NASA and international astrophysicists, saying Beijing won a reckless gamble. The uncontrolled fall of the rocket stoked fears that it may fall into inhabited areas.
Ji played down concerns, saying that the last stage of all types of launches was treated with passivation technology and will not explode in orbit or generate space debris.
"The Shenzhou cargo ship will deorbit and re-enter the atmosphere for destruction after all pre-set tasks are completed in a controlled manner with only minimum wreckage falling into the South Pacific waters," Ji said.