Long March 3B lofts BeiDou-3 spacecraft
Long March 3B launches BeiDou-3 G1Q satellite on November 1, 2018. Photo Credit: Xinhua
Using a Long March 3B booster a new geosynchronous spacecraft for the country’s BeiDou satellite navigation system was sent to orbit on Thursday, November 1. The satellite, designated BeiDou-3 G1Q, expands China’s BeiDou network to 17.
The flight got underway at 11:57 p.m. local time (15:57 GMT / 11:57 a.m. EDT) from Launch Complex 2 (LC-2) at the Xichang Satellite Launch Center (XSLC) located in China’s Sichuan Province.
Very little information has been available from Chinese media outlets regarding Thursday’s launch. The state-run Xinhua press agency confirmed the success of the mission some nine and a half hours after liftoff. However, it did not offer many other details about the satellite’s ride to orbit, instead it concentrated on the BeiDou system as a whole.
“China’s homegrown global satellite navigation system came a step closer to completion Thursday with the launch of another BeiDou-3 satellite (…) Launched on a Long March 3B carrier rocket, it is the 41st of the BeiDou navigation system, and will work with 16 other BeiDou-3 satellites already in orbit,” Xinhua said in a press release.
Given that BeiDou-3 G1Q was inserted into a geosynchronous orbit at an altitude of about 22,370 miles (36,000 kilometers), the flight most likely lasted several hours.
Artist’s depiction of BeiDou satellite in orbit. Image Credit: China Academy of Sciences
Developed by China Academy of Space Technology (CAST), BeiDou-3 G1Q has a mass of approximately 4.6 metric tons and is based on the DFH-3B bus. This satellite platform, designed for geosynchronous orbit, features a phased array antenna for navigation signals and a laser retroreflector and deployable S/L-band and C-band antennas. The spacecraft is also fitted with power-generating solar arrays.
Xinhua noted that besides its radio navigation system, BeiDou-3 G1Q is also comes equipped with an improved radio determination satellite service that can provide short message services to about 10 million subscribers each hour. The spacecraft should be capable of providing low-cost and reliable navigation services to civil aviation clients at home and abroad.
“If a navigation signal went wrong, the satellite could inform users within six seconds to switch other signals,” said Pan Yuqian, chief designer of the BeiDou-3 series.
BeiDou-3 G1Q belongs to the third phase of the BeiDou (BDS) satellite navigation system. Named after the Chinese term for the Big Dipper constellation, the project was formally launched in 1994 with the first satellite sent aloft in 2000. By 2012, a regional network had begun to take shape, which provided positioning, navigation, timing, and short message services in China as well as several other Asian countries.
China has stated its intention to have the BeiDou-3 constellation consist of some 27 BeiDou-3M satellites in MEO, five BeiDou-3G satellites in geostationary orbits, and three BeiDou-3I satellites in an inclined geosynchronous satellite orbit. The first BeiDou-3 satellite was launched in March of 2015.
“By around 2020, when the BeiDou system goes global, it will have more than 30 satellites,” Xinhua acknowledged.
The three-stage Long March 3B rocket used for Thursday’s flight is currently the most powerful Chinese launch vehicle in service. The 180-foot (55-meter) tall booster was developed by the China Aerospace Science and Technology Corporation (CASC). It is capable of sending up to 12 metric tons of payload into low-Earth orbit (LEO) or 5 metric tons of cargo into geostationary transfer orbit (GTO).
The 3B/E version that was used on this mission is an enhanced variant of the rocket, featuring an enlarged first stage and boosters. This iteration of the rocket was introduced in 2007 to increase the vehicle’s GTO cargo capacity and lift heavier geosynchronous equatorial orbit (GEO) communications satellites.
Thursday’s flight was the 290th mission of the Long March rocket series and the 32nd launch conducted by China in 2018. This is already a record-breaking year for Beijing in the number of space missions.
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