China plans to launch the Shenzhou XIII manned mission early on Saturday morning, sending three astronauts to spend six months inside the Tiangong space station.

Lin Xiqiang, deputy director of the China Manned Space Agency, said at a news conference on Thursday at the Jiuquan Satellite Launch Center in northwestern China that the mission will also see the first spacewalk by a Chinese woman.

It is expected to become the longest space journey by Chinese astronauts, doubling the time their peers spent on the Shenzhou XII mission.

The Shenzhou XIII spacecraft is scheduled to be launched at 12:23 am on Saturday by a Long March 2F carrier rocket at the Jiuquan center to take mission commander Major General Zhai Zhigang, Senior Colonel Wang Yaping and Senior Colonel Ye Guangfu to Tiangong's core module, Tianhe, or Harmony of Heavens, Lin said at the news conference.

Pioneering moments

Wang became the second female astronaut to take part in a spaceflight as a crew member of the Shenzhou X mission in June 2013.Liu Yang, who took part in the Shenzhou IX mission in June 2012, was China's first woman in space.

During the upcoming mission, she will become the first Chinese woman to enter the Tiangong, or Heavenly Palace, space station and carry out a spacewalk, Lin said.

Zhai is the first Chinese astronaut to conduct a spacewalk, a feat he achieved in September 2008 during the Shenzhou VII mission, which he commanded. The upcoming mission will be Ye's first spaceflight.

"According to our plan, the Shenzhou XIII crew will undertake a wide range of tasks, such as performing two to three spacewalks to install a small robotic arm onto a larger one; verifying key procedures and technologies like manual control of the robotic arms and robotic arm-assisted movement of station modules; checking the performance and capability of devices inside the station; and testing support instruments for astronauts' life and work in long-term flights," Lin said.

The astronauts will conduct scientific experiments and technology demonstrations in space medicine, microgravity physics and other fields. They will also deliver educational lectures that will be televised for Chinese students to watch, Lin said.

Huang Weifen, the chief trainer of Chinese astronauts, said that to help the Shenzhou XIII crew to better prepare for the coming flight and familiarize themselves with the station as quickly as possible, mission planners arranged video and face-to-face meetings between them and the Shenzhou XII astronauts, who shared their experiences of living and working inside the Tiangong.

Shenzhou XIII will be the fourth spacecraft to visit the Tiangong station and the second crewed ship to transport astronauts to the orbiting outpost.

The first astronauts inside Tiangong－Major General Nie Haisheng, Major General Liu Boming and Senior Colonel Tang Hongbo－finished their 92-day mission in mid-September.

During that mission, the astronauts made two spacewalks and used a large robotic arm and other equipment to install and adjust devices outside the station. They also performed a number of scientific experiments and technological tests, and made video calls with President Xi Jinping and hundreds of researchers, teachers and students in Hong Kong.

One of China's most challenging and sophisticated space endeavors, Tiangong will eventually consist of three main components－the Tianhe core module attached to two large space labs－with a combined weight of nearly 70 metric tons. The entire station is set to operate for about 15 years in a low-Earth orbit about 400 kilometers above the planet.

Tianhe was put into space by a Long March 5B heavy-lift rocket at the Wenchang Space Launch Center in Hainan province in late April.

The biggest and heaviest spacecraft China has ever constructed, Tianhe is 16.6 meters long and has a diameter of 4.2 meters. The craft's weight, 22.5 tons, is equal to the combined weight of 15 standard-size automobiles. It has three parts: a connecting section, a life-support and control section, and a resources section.

The spacecraft is now connected with the Tianzhou 2 robotic cargo ship, which was launched from the Wenchang facility in late May, and the Tianzhou 3, which was launched from Wenchang last month. The spacecraft stack is in good condition and is ready for rendezvous and docking with Shenzhou XIII, Lin said.

Shenzhou XIII will be the last mission in the technological verification phase of the Tiangong space station program.

Construction to continue

In 2022, two large space labs will be launched to connect with the core module. Two manned missions and two robotic cargo flights will be made that year to continue construction of the Tiangong station, which is scheduled to be completed and start formal operations toward the end of 2022.

Lin said that China welcomes foreign participation to the Tiangong program and will send foreign astronauts to the station after it is completed.

"In the near future, China will also deploy a space telescope to fly alongside the Tiangong station. The telescope will briefly dock with the station to resupply and for maintenance and upgrades," he said.