Twin BeiDou Satellites Launched Aboard a LM-3B/Yuanzheng 1

A LM-3B carrier rocket sits on the launch pad waiting for launch Photo:XIAO Guojun

China successfully sent the 52nd and 53rd satellites of the BeiDou Navigation Satellite System (BDS)into their preset orbit with a LM-3B/Yuanzheng 1 launch vehicle from the Xichang Satellite Launch Center at 15:22 Beijing time on December 16,2019.

The launch marked the fact 24 MEO satellites of BDS-3 have all been successfully launched into space,and the deployment of the core BDS-3 constellation system has been completed,further improving service performance and the user experience,thus laying a solid foundation for global networking.

The two BeiDou-3 MEO satellites were developed by the China Academy of Space Technology (CAST)under CASC.As the main force of the BDS-3 constellation system,the satellites mainly provide navigation,positioning and timing services,as well as global short message communication and international search and rescue services for global users.

The LM-3B/Yuanzheng 1 launch vehicle was developed by the China Academy of Launch Vehicle Technology (CALT).It is a member of the LM-3A series launch vehicle family which is composed of a basic stage and an upper stage.

该区域加深钻井采用高密度钻井液支撑井壁，提高抑制性能防止泥页岩水化分散脱落，并选择合适钻井工艺防塌措施的施工方案。以152井为例，该井钻井液密度控制为1.85～1.90g／cm3，漏斗黏度为50～70s，pH值为9～11，切力为（8～12）／（15～20）Pa／Pa，动切力为12～16Pa，塑性黏度为25～35mPa·s，常规滤失量为3～5mL，高温高压滤失量（150℃）为8～10mL，固相含量36%～40%，含砂量为0.3%～0.5%。

A LM-3B/Yuanzheng 1 launch vehicle is lifting off from the Xichang Satellite Launch Center,sending two BeiDou satellites into orbit Photo:XIAO Guojun

Up to now,the LM-3A series launch vehicle has successfully completed all the 12 missions in 2019 which is about 50% of the missions of LM series launch vehicle,becoming the most frequently launched carrier rocket in China for 5 years in a row.

具体的做法以我公司需要开发的产品或教学资源为校企合作课题，让学校的骨干教师来参与合作开发软硬配套的新产品，这样可以达到培养