Today, at 10:43 am Beijing time (UTC+8), China launched a pair of remote sensing satellites using the Long March 2C launch vehicle from Jiuquan Satellite Launch Centre. Today’s launch marked the maiden flight of China’s new upper stage, Yuanzheng-1S (YZ-1S), designed for smaller payloads. Designed to enhance the Long March 2C, China’s two-stage launch vehicle with an optional third stage, YZ-1S has increased the rocket’s payload capacity from 1.2 tonnes to 2 tonnes to the Sun Synchrous Orbit (SSO).
The launch today carried two satellites from China’s Yaogan family of remote sensing satellites to SSO. Both satellites are part of Yaogan-32, the 32th series of the Yaogan family, with Yaogan-1 having been launched in 2006. The two Yaogan-32 satellites were developed by Aerospace Dongfanghong Satellite Co., a company owned by the government through the Chinese Aerospace Science and Technology Corporation (CASC) and the China Academy of Space Technology (CAST). According to CASC, the satellites will be used for electromagnetic environmental monitoring.
YZ-1S is a simplified version of the Yuanzheng-1 (YZ-1) restartable upper stage, which was introduced in February this year to place 2 BeiDou navigation satellites into individual orbits. Whereas YZ-1 is used as a fourth stage on the Long March 3B and Long March 3C vehicles to send payloads into Medium Earth Orbit (MEO) and Geostationary Transfer Orbit (GTO), YZ-1S will be used for short flights, with CASC targeting commercial payloads.
According to CASC, Yuanzheng-1S differs from Yuanzheng-1 in several ways: the engine of Yuanzheng-1S allows for suborbital ignition as opposed to orbital ignition, and also has a reduced flight time of 10 minutes as compared to its parent’s 6-7 hours. The satellites are also positioned differently, with the ability for the first satellite to separate after the first ignition, as compared to a later separation in Yuanzheng-1.