Complex sentence: The "Long March 11" is a solid-fuel rocket that applies China's largest solid-fuel rocket engine and was designed to meet the need to rapidly launch satellites in case of emergencies or disasters.
Split into simpler sentences: The "Long March 11" is a solid-fuel rocket being developed by China. It will apply China's largest solid-fuel rocket engine and was designed to meet the need to rapidly launch satellites in case of emergencies or disasters.