China is one step closer to being the only nation with its own space station , with launch of a cargo spacecraft sending supplies to its orbital lab , a mission delayed for over a week for technical reasons. The Tianzhou 2 lifted off aboard a Long March 7 (CZ-7) rocket at 8.55pm on Saturday from the Wenchang spacecraft launch site in the southern island province of Hainan. Unspecified technical delays scuppered plans to launch the spacecraft on Thursday last week and the next day. The Tianzhou 2 launch is an important step in China’s plan to build its own fully autonomous space station. It is transporting 4.7 tonnes of spare parts for the station, laboratory equipment and supplies for the three Chinese astronauts on the three-month Shenzhou 12 mission originally scheduled to start in June. It is also carrying nearly 2 tonnes of fuel to resupply the station by connecting to its engine via robotic pipes. It is unclear if the launch date of Shenzhou 12 will also be pushed back because of the delay to Tianzhou 2’s launch. A source with China’s manned space programme said the previous delay was due to technical problems in the system used to cool the platform during launch. “Wenchang’s launch platform can spray 400 tonnes of water within 20 seconds. As the maximum temperature of the flame during the launch process can reach 3,000 degrees Celsius. We need it to function to cool down the platform and protect the equipment,” said the source. What is the Tianzhou 1 and why does it matter in China’s ambitious space mission? The Tianzhou vehicle is the world’s largest cargo spacecraft, with a payload of 6.5 tonnes. The most recent Dragon craft from Elon Musk’s SpaceX company, has closed the gap with a 6-tonne cap. China’s Tianzhou is also expected to deployed a powerful 10-metre robotic arm capable of grabbing and lifting a 20-tonne object, to help astronauts set up the station. The robotic arm will need to crawl to the right spot, find and grab the cargo ship after it unloads the fuel, and disconnect from the core module, moving it to another side of the module and reconnect it to a new docking port. The core module of the Tiangong, named Tianhe, was sent to space on April 29, carried by a Long March 5B (CZ-5B) heavy-lift rocket. The remains of that rocket drew international attention when it fell back to Earth this month. Officials at US space agency Nasa criticised China for failing to uphold international standards regarding space debris. China was excluded from the International Space Station, largely at the insistence of the US. The ISS is a multinational project involving the space agencies of the US, Russia, Canada, Japan, as well as the European Space Agency, which represents 22 European member states. Tiangong is China’s first permanent space station after two pilot predecessors, Tiangong 1, from 2011 to 2018, and Tiangong 2, from 2016 to 2019. Once the 100-tonne station is completed, it is expected to be in operation for at least 10 years, with the capacity to host three permanent residents and three visitors.