China launched three Diting-01 satellites aboard a Lijian-1 Y18 rocket from Jiuquan Satellite Launch Centre on Sunday, expanding a constellation designed for space-based electromagnetic monitoring.

The mission, which took off from the Gobi Desert site, adds to a system that Beijing has described as capable of detecting and locating electromagnetic signals, including those emitted by spacecraft. The Diting series - the name means "Earth Listener" - has been positioned by Chinese state media as a tool for space environment monitoring and scientific research.

The launch comes three days after the U.S. Air Force secretary disclosed that the United States has deployed space control weapons, a development this paper reported on Sept. 20. China has not commented on whether the Diting-01 satellites serve a military purpose, and the payloads' specific capabilities beyond electromagnetic monitoring have not been detailed by Chinese authorities.

The Lijian-1 rocket, a solid-fuel vehicle developed by the Chinese Academy of Sciences, has now flown 18 missions. Sunday's launch was the first in the Diting-01 series to carry three satellites on a single flight, suggesting the constellation is being built out at a faster pace than earlier single-satellite launches.