China News Service, Beijing, November 13th. Title: After a lapse of four years, we successfully launched the Tiantong-1 02 satellite together with the Changsan B rocket

  Author Guo Chaokai Wang Chu

  At 23:59 on November 12, Beijing time, a huge roar resounded through the mountains.

The Long March 3B carrier rocket ignited and lifted off at the Xichang Satellite Launch Center, lifting the Tiantong-1 02 satellite straight into the sky.

The satellite was successfully sent into the scheduled orbit, and the launch mission was a complete success.

The successful launch of Tiantong No.1 02 satellite: Guo Wenbin

  Unlike the past, the Long March IIIB rocket used for this mission has effectively improved the reliability and carrying capacity of the rocket through two technical improvements.

Joining hands again after four years

  The Long March 3B rocket was developed by the China Academy of Launch Vehicle Technology affiliated to China Aerospace Science and Technology Corporation.

This mission is not the first cooperation between the Long March 3B rocket and the Tiantong-1 satellite.

  As early as August 6, 2016, also at the Xichang Satellite Launch Center, the first satellite of China's satellite mobile communication system, Tiantong No. 1, was launched into space by the Long March 3B rocket.

Therefore, this launch mission is also four years later, the Long March IIIB rocket and the Tiantong-1 satellite once again joined hands.

  According to reports, the Tiantong-1 satellite mobile communication system is a satellite mobile communication system independently developed and constructed by China and an important part of China's space information infrastructure.

The launch of the Tiantong-1 02 satellite is based on the Dongfanghong-4 satellite platform. The core components have been independently controllable, and the key technologies have independent intellectual property rights.

Integrated forming of the bottom of the box

  The bottom of the box is currently the most complicated product, the most difficult to manufacture, and the longest production cycle in the rocket tank. The replacement of the traditional tailor-welded method with integrated manufacturing will greatly improve the accuracy and reliability of the product.

The successful launch of Tiantong No.1 02 satellite: Guo Wenbin

  For the first time, the Long March 3B rocket used a 2.25-meter-diameter integrated spinning-formed tank bottom.

The bottom of the storage box is integrally formed by spinning a piece of metal sheet. The integrated forming method overturns the traditional design and manufacturing mode of "1 top cover + 6 melon petals + 7 welds".

  Experts said that the integrated forming method eliminates a large number of welding seam X-ray inspections and the complicated process of welding seam internal pressure test assessment, which greatly shortens the forming welding time, inspection and assessment time, and shortens the manufacturing cycle of the tank bottom by 50%. At the same time, it reduces inspection costs and more effectively improves product reliability.

Carrying capacity increased by 10 kg

  As the rocket with the largest number of launches of a single model in China, the Long March A series rockets (including the Long March 3A, Long March 3B, and Long March 3C3 rockets) have become more mature and stable.

At the same time, the test team is also continuing to improve the reliability and carrying capacity of the rocket.

The successful launch of Tiantong No.1 02 satellite: Guo Wenbin

  In this mission, the test team optimized the rocket's three-stage engine pre-cooling program, and studied the cooling effect of low-flow pre-cooling on the engine. While reducing the large-flow pre-cooling time, it increased the low-flow pre-cooling time.

By adjusting the time ratio of the two pre-cooling modes, the consumption of propellant is reduced, and the foundation is laid for the subsequent improvement of carrying capacity.

When the optimized pre-cooling program is officially applied, the carrying capacity can be increased by 10 kg.

  This time, the Long March 3B rocket made new achievements and accurately sent the Tiantong-1 02 satellite into the predetermined orbit.

In the future, Tiantong-1 02 will provide users in China and surrounding areas, the Middle East, Africa and other related areas, as well as most of the Pacific Ocean and Indian Ocean, with stable and reliable mobile communication services, supporting voice, SMS and data. business.