Tiangong-2, China's second space lab, is undergoing tests before the launch, according to the chief designer of the lab.

The Tiangong-2 space lab will perform three tasks, including further testing on-orbit residence technology, verification of on-orbit propellant refilling technology and a number of experiments, said Zhu Congpeng, chief designer of the lab.

China will send Tiangong-2 into space in the third quarter of this year, which is expected to dock with a cargo ship scheduled to be launched in the first half of 2017, Wu Ping, a spokesperson from China's manned space program said on Feb. 28.

Two male astronauts will be onboard the lab who will conduct on-orbit residence that will last 30 days, Wu said. "No female astronaut is selected for this program," Wu added.

Before this, the longest space residence duration was made by astronauts onboard Shenzhou-10, lasting 15 days. Longer residence duration means more daily necessity, heavier payload of the spacecraft and more comfortable environment should be provided to astronauts, Zhu said.

Zhu said that the lab is also equipped with mechanical arms facilitating outboard maintenance.

In addition, according to Zhu, the lab will witness 14 space scientific and application experiments. Astronauts aboard are required to undertake two of these experiments.