Robots in Orbit: China develops space defence system to repel suspicious spacecraft

China is developing a rapid-response space defence system capable of intercepting suspicious spacecraft and pushing them away from critical orbital infrastructure, according to a senior scientist at the country’s top space research institution.

Sun Zhibin, a researcher at the National Space Science Centre in Beijing, outlined the concept during a public lecture at Nanjing University of Science and Technology, offering rare insights into China’s efforts to secure its Tiangong space station and other space-based assets, Caliber.Az reports, citing Chinese media.

“Sometimes another spacecraft may deliberately come close – maybe just to take a look – but it can still interfere with our operations,” Sun said. “In such cases, we first try to assess their intent. Then we choose how to respond – whether by dodging, adjusting our orbit, or releasing a small robot to grab and redirect the object.”

The envisioned system involves the deployment of small robotic thrusters that could latch onto unidentified or potentially hostile spacecraft and push them to a safe distance, mitigating collision risks and preserving the integrity of China's orbital infrastructure.

The announcement comes amid growing concerns about space security and close-approach incidents involving foreign satellites. In December 2021, China lodged a complaint with the United Nations after its space station was forced to conduct two evasive manoeuvres to avoid potential collisions with Starlink satellites operated by Elon Musk’s SpaceX.

According to the submission to the UN Committee on the Peaceful Uses of Outer Space, the Starlink-1095 and Starlink-2305 satellites descended from their operational orbit of 550 km into Tiangong’s flight zone around 380 km, prompting emergency manoeuvres on July 1 and October 21, respectively.

At the time, Tiangong was occupied by astronauts from the Shenzhou-12 and Shenzhou-13 missions. Harvard astronomer and satellite tracker Jonathan McDowell corroborated the near-miss claims, estimating that one of the satellites may have passed within just 3 km of the Chinese space station.

China's note to the UN emphasized that such incidents posed "dangers to the life or health of astronauts aboard the China Space Station" and highlighted that, under international law, states are responsible for all space activities, including those conducted by private companies.

The move to develop robotic defence mechanisms reflects a broader strategic shift among major space powers, with growing recognition of space as a contested domain. The United States has also pursued similar capabilities. The Defence Advanced Research Projects Agency (DARPA) is developing robotic systems that can inspect, service, or potentially manipulate satellites in orbit.

In a parallel development, the US is exploring space-based missile defence initiatives. The proposed "Golden Dome" project, a US$175 billion programme unveiled during the Trump administration, aims to intercept advanced threats such as hypersonic weapons and intercontinental ballistic missiles. The initiative names China as a primary concern, underscoring rising geopolitical competition in space.

By Khagan Isayev