INDO-PACIFIC China Launches New Communications Relay Satellite OE Watch Commentary: On 31 March, China launched the “Tianlian” [天链, lit. “sky chain”] 2-01 relay satellite on a Long March 3B rocket from the Xichang Satellite Launch Center in Sichuan. As the accompanying passage from Xinhuanet discusses, the Tianlian 2-01 represents an important link in China’s progress toward its goals for space. Relay satellites occupy geosynchronous orbits with an average altitude of over 35,000 km. Their greater altitude relative to the surface of the earth and stable orbit allows them to communicate with ground stations more effectively and with satellites in a wider range of orbits. The Tianlian-2-01 marks the first of a new generation of relay satellites that is meant to replace—or more likely, add redundancy to—its satellite communications network, communicate with spacecraft, and transfer data from imagery satellites. Previous launches stationed Tianlian satellites along the equator over the Indian Ocean and Central Pacific. The first generation of Tianlian satellites was launched beginning in 2008, making China the second nation to build a satellite relay system (after the U.S. Tracking and Data Relay Satellite System [TDRSS]). The Tianlian 2 is based on the Dongfanghong-4 东方红-4 communications satellite platform developed by the China Academy of Space Technology (CAST). The new generation of Tianlian satellites is expected to have a longer life and additional antennas, doubling the allowed transmission rate. Additionally, according to the article, the system computers have been substantially upgraded, improving The Launch of Long March 3B Rocket Source: AAxanderr via Wikimedia, https://upload.wikimedia.org/wikipedia/commons/2/2f/The_Launch_of_Long_March_3B_Rocket.jpg, Public mission management and allowing the satellite to send and receive Domain. from multiple sources simultaneously. In addition to stations scattered across China, the PRC currently maintains space tracking and communications ground stations in several parts of the globe, including Dongara, Australia, Kiruna, Sweden and outside Neuquén Argentina. China has also previously launched the Queqiao 鹊桥 relay satellite that enabled communications with the Yutu lander mission to the far side of the moon in January this year. End OE Watch Commentary (Wood) “..the Tianlian II-01 will provide data relay, measurement and control, transmission services for manned spacecraft, satellites, carrier rockets and other non-spacecraft users.” Source: “China launches new data relay satellite,” Xinhuanet, 1 April 2019. http://english.chinamil.com.cn/view/2019-04/01/ content_9464485.htm China sent a new data relay satellite into orbit from the Xichang Satellite Launch Center in southwest China’s Sichuan Province late Sunday night. The Tianlian II-01 satellite was launched at 11:51 p.m. Beijing Time by a Long March-3B carrier rocket. As the first satellite to constitute China’s second-generation data relay satellite network, the Tianlian II-01 will provide data relay, measurement and control, transmission services for manned spacecraft, satellites, carrier rockets and other non-spacecraft users. The Tianlian II network will be markedly more advanced in mission planning, system management and operations than the first-generation network composed of Tianlian I satellites. The new network, with faster data transfer and higher multi-objective service capability, will play an important role in improving the transmission promptness, in-orbit security and mission flexibility for medium- and low-Earth orbiting satellites and manned spacecraft. The satellite is developed by the China Academy of Space Technology under the China Aerospace Science and Technology Corporation. The launch marks the 301st mission of the Long March carrier rocket series. OE Watch | May 2019 33.