BEIJING (PTI): China today successfully launched a second lab module to be part of its ambitious space station currently under construction.

The lab module called Mengtian was launched using a Long March-5B Y4 rocket, one of China's biggest rockets, from the Wenchang Spacecraft Launch Site on the coast of the southern island province of Hainan.

The launch was telecast live by the news channels here. About 10 minutes into the launch, an official of the China Manned Space Agency announced that the mission was successful and the spacecraft reached its intended orbit.

Later, it will dock with the orbiting core module of the space station.

Scientific equipment in the Mengtian module, the second lab component of China's under-construction space station, will be used for studying microgravity and carrying out experiments in fluid physics, materials science, combustion science, and fundamental physics, the state-run Xinhua news agency reported.

The Wentian lab which was sent earlier focused more on biological and space life sciences.

Also, the Mengtian will carry the world's first space-based set of cold atomic clocks consisting of a hydrogen clock, a rubidium clock, and an optical clock.

"If successful, the cold atomic clocks will form the most precise time and frequency system in space, which should not lose one second in hundreds of millions of years," said Zhang Wei, director of the Utilisation Development Centre of Technology and Engineering Centre for Space Utilisation under the Chinese Academy of Sciences told the state-run Global Times recently.

China is currently building its space station and according to an announcement by the China Aerospace Science and Technology Corporation (CASTC) its construction was expected to be completed this year.

Two batches comprising three astronauts were flown to the space station, the main module called Tianhe on a six months mission to complete the construction.

While one set of astronauts returned, another set of three astronauts is currently based in Tianhe to complete its construction.

Once ready, China will be the only country to own a space station. The International Space Station (ISS) of Russia is a collaborative project of several countries.

China Space Station (CSS) is also expected to be a competitor to the ISS built by Russia.

Observers say the CSS may become the sole space station to remain in orbit once the ISS retires in the coming years.

The significant feature of China's under-construction space station is its two robotic arms, especially the long one over which the US has previously expressed concern over its ability to grab objects including satellites from space.