On March 21, Chinese officials reported the sale of an advanced tracking system used to develop missiles to Pakistan. Zheng Mengwei, a researcher with the Chinese Academy of Sciences (CAS) Institute of Optics and Electronics, confirmed that the purchase was of a “highly sophisticated large-scale optical tracking and measurement system.” Optical systems play a critical role in missile testing and development, providing missile developers with valuable visual information during fight. The CAS said a Chinese team spent three months in Pakistan helping assemble and calibrate the system, in addition to training technical staff on how to use it. China has long been reported to support Pakistan’s missile program, but official confirmation its role is rare.