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January 12, 2018
Long March 3B carrying Beidou-3M launches. Image Credit: Xinhua
A new pair of navigation satellites were successfully launched by China on Thursday, using a Long March-3B/YZ-1. The launch of the Beidou-3M pair took place at around 23:18 UTC from the LC2 Launch Complex of the Xichang Satellite Launch Center, Sichuan province. It took over four hours to complete the mission.
The launch was previously scheduled for 2017. However, this was delayed due to a partial launch failure with a previous launch of this rocket during the Zhongxing-9A (ChinaSat-9A) mission, which resulted in the satellite being lofted to a lower than planned orbit.
China Sends Twin Beidou-3 Navigation Satellites into Space
It is expected that the Beidou-3MEO3 (Beidou-26) and Beidou-3MEO4 (Beidou-27) satellites will be onboard, but a TV news report following last November’s BDS launch – featuring the satellite production facility in Shanghai – referred that the two satellites about to be shipped were marked as “M7 & M8”. So, we will have to wait what designation is given to the satellites when in orbit.
The MEO satellites are the Medium Earth Orbit component of the 3rd phase of the Chinese Beidou (Compass) satellite navigation system. The satellites are part of a fleet that will expand the system to a global navigation coverage.
The satellites are using a new bus that features a phased array antenna for navigation signals and a laser retroreflector, with a launch mass 1,014 kg. Spacecraft dimensions are noted to be 2.25 by 1.0 by 1.22 meters. Usually, the satellites reside in a 21,500 – 21,400 km nominal orbit at 55.5 degrees.
Beidou-3 satellite. Image Credit: J. Huart
The Beidou Phase III system includes the migration of its civil Beidou 1 or B1 signal from 1561.098 MHz to a frequency centered at 1575.42 MHz – the same as the GPS L1 and Galileo E1 civil signals – and its transformation from a quadrature phase shift keying (QPSK) modulation to a multiplexed binary offset carrier (MBOC) modulation similar to the future GPS L1C and Galileo’s E1.
The Phase II B1 open service signal uses QPSK modulation with 4.092 megahertz bandwidth centered at 1561.098 MHz.
The current Beidou constellation spacecraft are transmitting open and authorized signals at B2 (1207.14 MHz) and an authorized service at B3 (1268.52 MHz).
For more information about China Aerospace Science and Technology Corporation (CASC), visit: http://english.spacechina.com/n16421/index.html
Images, Video, Text, Credits: CASC/Xinhua/J. Huart/CCTV+/NASA Spaceflight.com/Rui C. Barbosa.