A Long March-5B Y4 carrier rocket blasted off from a launchpad at the Wenchang spaceport in South China's Hainan province on Monday carrying a second lab module for China's space station. When in place, the Mengtian lab module will complete the space station's basic T-shaped structure, which means that the space station will be able to perform all its designated functions.

Mengtian is the second lab module for the space station. The first is the Wentian module which is already docked with the Tianhe core module.

While Wentian is to be used for biological and space life science projects, such as observing the growth of multiple kinds of plants, animals and microbes in space, Mengtian will be used for in-orbit experiments dedicated to physics and material sciences and will focus on micro-gravity experiments.

As well as being a lab module, Mengtian will also act as a backup for the core module when it is undergoing maintenance. And with Mengtian in place, the space station will be able to host more astronauts. There are three astronauts on board the space station at the moment. When Shenzhou XV arrives with a change of crew, scheduled for early December, there will be six Chinese astronauts living on the space station for a time until the return of the Shenzhou XIV mission crew members.

China's space station will be the only one in space in 2024, if an agreement can't be reached on extending the life of the International Space Station. The ISS was due to be decommissioned in 2031, but that might not be feasible since it requires the cooperation of the United States and the European Union with Russia.

That the ISS is even still operational at this point is a testament to its design and engineering. Like the ISS, China's space station will have to withstand tremendous stresses and strain. While the power, environmental control and life support, and communications systems are all repairable or replaceable in orbit, the operational lifetime of the spacecraft is limited by the integrity of the primary structure. This has to bear the strain of repeated vehicle dockings and undockings, and the stress effects of daily temperature swings of about 278 degrees Celsius in either direction.

Mengtian means "dreaming of heaven" in Chinese. And China's space station will not only carry the nation's dream of exploring space, but also that of humankind as a whole when the ISS meets its fiery fate.

China views learning more about the vast cosmos as a common dream of humankind, and researchers from other countries already have access to China's orbiting laboratory. China has selected nine initial international experiments for the space station through a collaborative project with the United Nations, and more are to follow. It is also anticipated that the space station will host astronauts of various nationalities during its lifetime as China is encouraging international space exchanges and cooperation to help protect the Earth, improve people's well-being and serve human progress.