According to ancient records, the word "rocket" first appeared in the Three Kingdoms era in the 3rd century AD and has a history of more than 1,700 years. At that time, in the battle between the enemy and ourselves, people called an arrow with a flammable substance on the head, which was ignited and shot at the enemy, and which carried fire when flying. This is a weapon used for fire attacks. In essence, it is just an arrow with "fire", which is far different in meaning from what we now call rockets. After the invention of gunpowder in the Tang Dynasty, in the Song Dynasty, people tied the tube containing gunpowder to the arrow shaft, or filled the arrow shaft with gunpowder, lit the fuse and shot it out. The arrow burned backwards with the help of gunpowder and sprayed fire during flight. The reaction force makes the arrow fly farther, and people call this fire-breathing arrow a rocket. The rockets of the Song Dynasty sprayed fire backwards and used reaction force to boost the rockets into the air. They were the prototype of modern rockets and are called the most primitive solid rockets.