China launched a Long March-4B rocket carrying the Yaogan-21 remote sensing satellite and an experimental satellite, Tiantuo-2, from the Taiyuan Satellite Launch Centre on 8 September.
Tiantuo-2, which was designed and built by the National University of Defence Technology (NUDT), “will be used for scientific experiments, natural resource survey, estimation of crop yields, and disaster relief,” according to Xinhua news agency.
This is the function China ascribes to most of its remote sensing satellites, but analysts believe that the Yaogan constellation is used for ocean surveillance.
The launch was the latest in a series by China. On 9 August a Long March-4C rocket launched the Yaogan-20 mission into orbit from the Jiuquan Satellite Launch Centre. While Xinhua reported the payload to be a satellite with the same purposes as the Yaogan-21, other sources indicate that the payload comprised three satellites, which were deployed in such a way that would make them suitable for operating as an ocean surveillance system.
Analysts believe that a range of sensors, encompassing electro-optical imaging, electronic intelligence (ELINT) intercept, and synthetic aperture radars, are carried by Yaogan series satellites. The first of the series, Yaogan-1, was launched on 27 April 2006 and is believed to have deployed China’s first space-based synthetic aperture radar. Yaogan-9, launched on 5 March 2010, was the first deployment of a triple satellite formation, followed by similar deployments from Yaogan-16 in November 2011 and Yaogan-17 in September 2013. The Yaogan-20 triplet, which is possibly a replacement for Yaogan-9, is believed to be for ELINT, detecting ships’ radar emissions, and determining emitter location through triangulation.
Internet sources, citing Xinhua, report that the experimental Tiantuo-2 carries four video cameras capable of streaming real-time data on moving objects. It is speculated that the system will be capable of tracking objects on the earth’s surface using real-time ground-controlled directional alignment of the cameras. An NUDT statement reported that the satellite will be used to test technologies for more advanced video imaging satellites.
The first Chinese satellite launch of 2014 was on 31 March and was of Shijian 11-06 (SJ-11-06). Chinese media reported this as an experimental satellite and provided no further details. However, the positioning of the Shijian 11 constellation, and similarities to the launch vehicle and orbit of Shiyan Weixing 2 (SY-2), launched on 18 November 2004, which tested IR sensors, has led some analysts to believe that the purpose is to support a ballistic missile early warning system, with satellites equipped with infrared sensors to detect missile launches. SJ-11-06 is the fifth satellite in the constellation; SJ-11-04 was lost in August 2011 after failure of the second stage of the launch vehicle.