Sunday, July 29, 2018

Long March 3B with BeiDou-3 Satellite Duo Lifts Off from Xichang

Long March 3B rocket lifts off with two BeiDou-3 satellites on July 29, 2018. Photo Credit: Xinhua/Liang Keyan

Lifting off from the Xichang Satellite Launch Center (XSLC) in China’s Sichuan Province, a Long March 3B booster orbited on Sunday, July 29, a duo of BeiDou-3 spacecraft for the country’s homegrown satellite navigation system.

The rocket thundered off the launch pad at 1:48 GMT (9:48 p.m. EDT on July 28) to commence a ride to a medium-Earth orbit (MEO). The flight lasted three hours in order to place the dual payload into targeted orbital spot.

Launch success was confirmed by the Xinhua press agency nearly seven hours after after liftoff.

"China on Sunday sent twin satellites into space via a single carrier rocket, entering a period with unprecedentedly intensive launches of BeiDou satellites,” Xinhua reports.

The launch was originally planned for March 29, 2018, however it was postponed to June 23 and then once again rescheduled to July 29. What was behind the delays remains unknown as Beijing has not disclosed why these decisions were made.

Long March 3B rocket flew in a configuration with a Yuanzheng-1 (YZ-1) upper stage as was the case with previous BeiDou-3 launches. This stage ignited its YF-50D engine some 20 minutes after liftoff and burned out about six hours into the flight, deploying the navigation satellites into MEO at an altitude of some 13,360 miles (21,500 kilometers), with an inclination of approximately 55.5 degrees.

As usual the details of the mission are shrouded in secrecy. China keeps the information about its BeiDou launches under tight wraps, not informing the public about pre-launch preparations and not revealing the exact timelines of the orbital flights.

What is known is that the passengers of Sunday’s flight are designated BeiDou-3 M5 and M6. Both spacecraft are based on a newly-developed dedicated satellite bus and weigh about one metric ton a piece. They have two deployable solar arrays and were designed to be operational for about 12 years.

The two spacecraft belong to the third phase of the BeiDou (BDS) satellite navigation system and are the 33rd and 34th satellites of the program. Named after the Chinese term for the plough or the Big Dipper constellation, the project was formally launched in 1994 and the first BeiDou satellite was launched in 2000. By 2012, a regional network had already begun to take shape, which provided positioning, navigation, timing, and short message services in China and several other Asian countries.

If everything goes according to the plan, BeiDou-3 constellation should consist of 27 BeiDou-3M satellites in MEO, five BeiDou-3G satellites in a geostationary orbit (GTO), and three BeiDou-3I satellites in an inclined geosynchronous satellite orbit (IGSO). The first BeiDou-3 satellite was launched in March of 2015.

According to Xinhua, the BDS system currently covers more than 50 countries with a total population of more than three billion. By 2020, BeiDou is expected to have more than 30 operational satellites in orbit.

The three-stage Long March 3B rocket that was launched Sunday is a 180-foot (55-meter) tall launch vehicle that is capable of sending up to 12 metric tons of payload to low-Earth orbit or 5 metric tons of cargo into GTO. For some launches, this rocket can be equipped with a Yuanzheng-1 upper stage.

Sunday’s liftoff marked the 281st flight of the Long March rocket series and the 21st mission carried out by China in 2018. Beijing’s next orbital launch is scheduled for Tuesday, July 31, when a Long March 4C booster is slated to blast off with Gaofen 11 Earth-observing satellite.

No comments:

Post a Comment