The Tianzhou 9 robotic spaceship was launched on Tuesday morning in Hainan province, marking the first and only cargo mission to China's Tiangong space station this year.

A Long March 7 rocket, carrying the cargo vessel on top, lifted off at 5:34 am from the Wenchang Space Launch Center located along Hainan's southeastern coast, according to the China Manned Space Agency.

After a short flight, the rocket placed Tianzhou 9 in its preset low-Earth orbit, and the solar wings on the robotic vessel unfolded, marking the successful completion of the launch mission. About three hours later, the spacecraft docked with the space station's Tianhe core module, the agency said in a news release.

As the 17th spaceship and eighth cargo vessel to dock with the Chinese space station, Tianzhou 9 is tasked with delivering propellants, science payloads and daily necessities for the Shenzhou XX astronauts, who have been in orbit for nearly three months, as well as for their successors, who will board the Shenzhou XXI spaceflight this winter.

Designed and built by the China Academy of Space Technology in Beijing, Tianzhou 9 — like its predecessors in the Tianzhou series — has the largest carrying capacity and the highest transport efficiency of its kind in the world, according to mission planners.

The vessel is carrying hundreds of packages with a combined weight of nearly 6.5 metric tons, including several science and technology apparatus and two new spacewalk suits. This is the heaviest cargo delivery any Tianzhou vessel has ever performed.

Gong Yongsheng, a researcher at the Chinese Academy of Sciences' Technology and Engineering Center for Space Utilization, said that Tianzhou 9 is carrying 776.5 kilograms of science payloads related to 23 experiments.

According to the Astronaut Center of China, the two new spacewalk suits feature optimized design and longer life span. Compared with the current type that can facilitate 15 spacewalks, the new ones will support 20.

In addition, the cargo vessel is carrying a workout instrument for astronauts to perform core-muscle exercises and more than 190 kinds of foods to offer crew members more options, the center said.

Orbiting Earth at about 400 kilometers above the ground, Tiangong is now the only space station in orbit that is independently operated by a single nation. It has three permanent components — a core module and two science capsules — and regularly connects with several visiting crew and cargo spaceships.

The Tianzhou 8 robotic spaceship, the predecessor of the current cargo vessel, undocked from the Tiangong space station on July 8 and reentered Earth's atmosphere the next morning guided by ground controllers.

Most of the spacecraft disintegrated and burned during reentry as expected, with a small amount of debris falling into designated areas of the ocean, the China Manned Space Agency said.