Long March 4B | Huanjing 2A, 2B

Huanjing (abbreviated as HJ) is a constellation of environmental monitoring satellites. The HJ-2A and HJ-2B are 16-meter optical satellites which will provide 16-meter multispectral, 48-meter hyperspectral and infrared image data.

The Long March 4B (Chinese: 长征四号乙火箭), also known as the Chang Zheng 4B, CZ-4B and LM-4B is a Chinese orbital carrier rocket. Launched from Launch Complex 1 at the Taiyuan Satellite Launch Center, it is a 3-stage rocket, used mostly to place satellites into low Earth and sun synchronous orbits.

The China Aerospace Science and Technology Corporation (CASC) is the main contractor for the Chinese space program. It is state-owned and has a number of subordinate entities which design, develop and manufacture a range of spacecraft, launch vehicles, strategic and tactical missile systems, and ground equipment. It was officially established in July 1999 as part of a Chinese government reform drive, having previously been one part of the former China Aerospace Corporation. Various incarnations of the program date back to 1956.