Wednesday, September 30, 2015

China Launches Long March 3B Rocket with Beidou-3 Navigation Satellite

A Long March 3B carrier rocket carrying a new-generation Beidou satellite lifts off from the Xichang Satellite Launch Center in Xichang, southwest China's Sichuan Province, Sept. 29, 2015. Photo Credit: Xinhua/Li Xiang

China successfully launched Tuesday its third-generation navigation satellite into orbit. The BDS I2-S satellite, lifted off atop the country’s Long March 3B launch vehicle at 7:13 p.m. EDT (23:13 GMT) from the Launch Complex 3 at the Xichang Satellite Launch Center. It is the 20th satellite for the Chinese Beidou Navigation Satellite System (BDS).

The rocket completed a short vertical ascent before aligning itself with a south-easterly trajectory towards an inclined geosynchronous satellite orbit (IGSO). It took the Chinese media over an hour to acknowledge the launch.

The BDS I2-S satellite represents the third phase of the BDS system (Beidou-3). It is the final stage of establishing Chinese space-based navigation architecture. The constellation will consist of 27 Beidou-3M satellites in medium Earth orbit (MEO), five Beidou-3G satellites in geostationary orbit (GTO) and three Beidou-3I satellites in IGSO.

The BDS I2-S spacecraft, weighing about 4.5 tons, uses a new bus that includes a phased array antenna for navigation signals and a laser retroreflector. The satellite that was launched Tuesday featured for the first time a hydrogen atomic clock. A series of tests related to the clock and a new navigation-signal system will be yet undertaken, according to a statement from the Xichang Satellite Launch Center. The satellite has an operational lifespan of 10 years.

The satellite has two navigation payloads – the Beidou-3 Radio Navigation Satellite Service (RNSS) and the heritage Radio Determination Satellite Service that provides compatibility with existing Beidou-1 terminals on the ground. RNSS is very similar to that provided by U.S. GPS and European Galileo system and is designed to achieve similar performances.

The first Beidou-3 satellite was launched in March 2015, the next two were delivered into orbit in July.

Named after the Chinese term for the plough or the Big Dipper constellation, the Beidou project was formally launched in 1994. The first Beidou satellite was not launched until 2000. Nonetheless, by 2012, a regional network had already taken shape, which provided positioning, navigation, timing and short message services in China and several other Asian countries.

China plans to expand the Beidou services to most of the countries covered in its "Belt and Road" initiative by 2018, and offer global coverage by 2020.

The three-stage Long March 3B rocket used in Tuesday’s mission is the most powerful Chinese launch vehicle. The 180 ft. tall booster is capable of launching up to 12 tons of payload into LEO or 5 tons of cargo into GTO. For the Sept. 29 launch, the rocket was equipped in a Yuanzheng-1 upper stage.

Thanks to the successful Tuesday’s lift-off, China wraps up a record-breaking month in the country’s history of spaceflight. In September, Chinese rockets have conducted five orbital launches in the span of only 18 days. China has already performed nine space missions this year, including the debuts of Long March 6 and 11 rockets and plans six more launches. The next launch is scheduled for Oct. 7, when a Long March 2D rocket will loft three Jilin-1 Earth observation satellites.

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