The YF-20 is a Chinese liquid-fuel rocket engine burning N2O4 and UDMH in a gas generator cycle. It is a basic engine which when mounted in a four engine module forms the YF-21. The high altitude variation is known as the YF-22 is normally paired with the YF-23 vernier to form the YF-24 propulsion module for second stages. New versions when used individually for booster applications are called YF-25.

The Long March 2E, also known as the Chang Zheng 2E, CZ-2E and LM-2E, was a Chinese orbital carrier rocket from the Long March 2 family. The Long March 2E was a three-stage carrier rocket that was designed to launch commercial communications satellites into geosynchronous transfer orbit. Launches took place from launch complex 2 at the Xichang Satellite Launch Center.